GeoMeast 2017
Sustainable Civil Infrastructures: Innovative Infrastructure Geotechnology 15-19 Luglio 2017, Sharm El-Sheik, Egitto ...

WLF4
4th World Landslide Forum - Landslide research and risk reduction for advancing culture of living with natural hazards, Ljubljana, Slovenia, 29 Maggio–2 Giugno 2017 ...

AGU Fall Meeting 2016
L'AGU Fall Meeting è la più vasta conferenza a livello mondiale nel campo delle geoscienze, San Francisco, 12-16 Dicembre 2016...

SPIE 2016
SPIE Remote Sensing Europe, Edimburgo, UK, 26-29 Settembre 2016 ...

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Pubblicazioni

 

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Negli ultimi venti anni, nell'ambito di progetti di ricerca finanziati dalla Comunità Europea dalle agenzie spaziali nazionali ed internazionali (ASI, ESA, NASA), sono state acquisite le seguenti competenze:

  • Radar ad Apertura Sintetica (SAR) data processing;
  • Sviluppo della catena di elaborazione interferometrica multitemporale (SPINUA © - Stable Points Identification in Non Urbanized Areas) per l'identificazione ed il monitoraggio di instabilità del suolo (subsidenze, frane, terremoti);
  • Analisi di dati telerilevati nel campo VIS/NIR acquisiti da piattaforme satellitari per la misura di parametri chimici e biofisici per la qualità delle acque costiere;
  • Elaborazione di dati meteorologici e climatologici; servizi di previsione meteorlogica ad elevata risoluzione spazio-temporale;
  • Sviluppo di algoritmi di signal & image processing utilizzando linguaggi di programmazione compilati o di scripting (MATLAB, SCILAB, IDL, C, C++) nonchè in Assembly;
  • Soluzioni informatiche per architetture parallele e di grid-computing.

Partendo da tale background scientifico, GAP intende fornire prodotti e servizi caratterizzati da un elevato contenuto di innovazione e scientifico/tecnologico nel campo del remote sensing e delle correlate tecnologie HW/SW:

  • Produzione, marketing e customer service;
  • Studi di fattibilità, progettazione, sviluppo e prototipizzazione di procedure innovative per il digital signal processing (DSP) dedicato in particolare a dati telerilevati satellitari;
  • Attività di formazione e training rivolte a tutti coloro che intendono affacciarsi alle tecnologie del telerilevamento;
  • Attività di ricerca e sviluppo per un aggiornamento continuo del know-how nei campi di nostro specifico interesse.

GAP contribuisce altresì all'organizzazione del Master in Tecnologie per il Telerilevamento Spaziale, master universitario di II livello organizzato da Università di Bari e promosso da Università di Bari, Politenico di Bari, Agenzia Spaziale Italiana e eGEOS.


Qui di seguito riportiamo l'elenco dei lavori pubblicati da ricercatori del Gruppo di Telerilevamento del Dipartimento Interateneo di Fisica "M. Merlin" di Bari e/o dello spin-off GAP srl.

International Conference Proceedings

  • [Was.GeoMeast2017] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti and M. T. Chiaradia, "High resolution satellite multi temporal interferometry for monitoring infrastructure instability hazards", Accepted for publication in Proceedings of GeoMEast 2017 International Conference, Sharm Elsheikh, Egypt, July 15-19, 2017.
    Advanced remote sensing techniques are now capable of delivering more rapidly high quality information that is sufficiently detailed (and cost-effective) for many engineering applications. Here we focus on synthetic aperture radar (SAR), multi-temporal interferometry (MTI). With radar satellites periodically re-visiting the same area, MTI provides information on distance changes between the on-board radar sensor and the targets on the ground (e.g., human-made structures such as buildings, roads and other infrastructure). The detected distance changes are thus interpreted as evidence of ground and/or structure instability. In settings with limited vegetation cover, MTI can deliver very precise (mm resolution), spatially dense information (from hundreds to thousands measurement points/km2) on slow (mm-cm/year) deformations affecting the ground and engineering structures. Radar satellites offer wide-area coverage (thousands km2) and, with the sensors that actively emit electromagnetic radiation and thus can "see" through the clouds, one can obtain deformation measurements even under bad weather conditions. We illustrate the potential of high resolution MTI and explain what this technique can deliver to assist in infrastructure instability hazard assessment. This is done by presenting selected examples of MTI applied to detect and monitor post-construction behavior of engineering structures. The examples are from Italy and include: an earthfill dam, an off-shore vertical breakwater built to protect an oil terminal, city buildings and a highway. We also stress that the current approach to the assessment of instability hazard can be transformed by capitalizing more on the presently underexploited advantage of the MTI technique, i.e., the capability to provide regularly spatially-dense quantitative information for large areas where engineering infrastructure may currently be unaffected by instability, but where the terrain and infrastructure history (e.g., aging) may indicate potential for future failures.
    ERS-1/2, Sentinel-1, and COSMO-SkyMed (CSK) data provided, respectively, by the European Space Agency (ESA) and Italian Spatial Agency (ASI). ERS products delivered by ESA under CAT-1 project n. 32017. CSK® Products© of ASI delivered by ASI under a license to use.

  • [Was.WLF4] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti and M. T. Chiaradia, "Detection and monitoring of slow landslides using Sentinel-1 multi-temporal interferometry products", Accepted for publication in Proceedings of 4th World Landslide Forum, Ljubljana, Slovenia, May 29 – June 2, 2017.
    Landslide investigations can now benefit from high quality information obtainable using multi-temporal interferometry (MTI) techniques (e.g., PSInSAR, SBAS) and images acquired by satellite synthetic aperture radars (SAR). MTI is only little affected by bad weather and can provide long-term (years), regular (weekly-monthly), precise (mm) measurements of ground displacements over large areas (thousands of km2), with the possibility of exploiting the same series of radar images for regional to slope-scale investigations. Spatially dense measurements can be obtained (from hundreds to thousands data per km2). Furthermore, by offering regular global-scale coverage, improved temporal resolution (from 12 to 6 days) and free imagery, the new radar satellite mission Sentinel-1 of the European Space Agency (ESA) can now guarantee wider and more efficient application of MTI to landslide investigations. In this work we demonstrate for the first time the excellent potential of MTI based on Sentinel-1 for the detection and monitoring of slope instabilities affecting small hilltop towns in the Apennine Mountains of southern Italy. The is done by comparing the MTI results based on Sentinel-1 images with those based on ENVISAT data (ESA satellite retired few years ago). The comparison shows that by using Sentinel-1 imagery a few times higher density of radar targets (measurement points) can be obtained. Thanks to this and more frequent measurement capability of Sentinel-1, landslide detection and monitoring can be more effective.
    Work supported by the Apulia Space project (PON&REC 2007-2013, Cod: PON03PE_00067_6). ENVISAT and Sentinel-1 imagery provided by the European Space Agency (ESA).

Peer-Reviewed Journal Articles

  • [Bru.ICS2016] Bruno, M. F., Molfetta, M. G., Mossa, M., Nutricato, R., Morea A. and Chiaradia, M. T., "Coastal observation through COSMO-SkyMed high-resolution SAR images," In: Vila-Concejo, A.; Bruce, E.; Kennedy, D.M., and McCarroll, R.J. (eds.), Proceedings of the 14th International Coastal Symposium (Sydney, Australia). Journal of Coastal Research, Volume 1, Special Issue 75, pp. 795–799. Coconut Creek (Florida), Print ISSN: 0749-0208. Online ISSN: 1551-5036. Scopus: 2-s2.0-84987719053. WOS:000373241300014 DOI: http://dx.doi.org/10.2112/SI75-160.1
    The study deals with the application and further improvement of an advanced Earth Observation system, named COSMO-Beach, developed for semi-automatic shoreline extraction and coastal morphology identification. The system exploits SAR Single-Look-Complex data acquired by the COSMO-SkyMed constellation, which is able to provide X-band images with a short revisiting time. The implemented procedures have been tested over a very popular beach in Apulia Region (Italy), affected by erosion problems induced by human activities. The outcomes of the COSMO-Beach system are presented and discussed.
    This work is one of the results of the project “Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential (CoCoNET)”. Project carried out using CSK® Products, © of the Italian Space Agency(ASI), delivered under a license to use by ASI. The authors are grateful to Prof. Antonio F. Petrillo and Prof. Luciano Guerriero for their suggestions and precious supervision and to dr. Davide Oscar Nitti for the fruitful collaboration.

International Conference Proceedings

  • [Bru.EESMS2016] M. F. Bruno, M. G. Molfetta, M. Mossa, R. Nutricato, D. O. Nitti, L. Guerriero, A. Morea, M. T. Chiaradia, A. Coletta, "Integration of Multitemporal SAR/InSAR Techniques and NWM for Coastal Structures Monitoring: Outline of the software system and of an operational service with COSMO-SkyMed data," Proc. of 2016 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems (EESMS), Bari (Italy), 13-14 June 2016, p.186-191 (2016). Scopus: 2-s2.0-84980349560. ISBN: 978-1-5090-2369-1. DOI: 10.1109/EESMS.2016.7504837. IF: 1.06 (Year: 2015 - Source: ResearchGate - https://goo.gl/ouCTJE)
    Continuous monitoring of coastal areas is a necessary condition for proper coastal activities regulation. Coastal area alterations, even in the short term, in fact, may lead to a significant social change in the development of economic activities and lifestyle in populations living in coastal regions. This paper deals with the development of an integrated operational Earth Observation system aimed to provide a complete monitoring system for both natural and built coastal environments. Three different software engines have been coupled to fully exploit the COSMO-SkyMed images using SAR and InSAR techniques (SPINUA and COSMO-Beach modules) providing also APD corrections computed using numerical weather simulations (NWM module). This allows to automate the entire radar image process chain to obtain a complete picture of the most important phenomena for large and small scale. The implemented system has been widely tested on COSMO-SkyMed images taken within the Map Italy program over two different Italian sites and results are presented and discussed.
    This research was partly supported by the CoCoNET project (“Towards COast to COast NETworks of marine protected areas (from the shore to the high and deep sea), coupled with sea-based wind energy potential”). CSK® Products, © of the Italian Space Agency (ASI), delivered by ASI under a license to use. ERS products delivered by ESA under CAT-1 project n. 32017. The computational work has been executed on the IT resources made available by ReCaS, a project financed by the MIUR (Italian Ministry for Education, University and Research) in the “PON Ricerca e Competitività 2007-2013 – Azione I – Interventi di rafforzamento strutturale” PONa3_00052, Avviso 254/Ric."

  • [Tij.EESMS2016] K. Tijani, A. Morea, M. T. Chiaradia, R. Nutricato, L. Guerriero, "Prototype of a multi-platform remote sensing service for fishing forecasting", Proc. of 2016 IEEE Workshop on Environmental, Energy, and Structural Monitoring Systems, p.237-242 (2016). Scopus: 2-s2.0-84980370560. ISBN: 978-1-5090-2369-1. DOI: 10.1109/EESMS.2016.7504846.
    The present work concerns the development of an automatic Fishing Forecasting System (FiFoS) where satellite observations, ancillary data and in situ measurements (Catch Per Unit Effort) are used to set up, calibrate and validate a fishing forecasting model. Multi-temporal and multi-sensor data fusion techniques are applied to multi-spectral data in order to detect chlorophyll and sea temperature fronts that according to physical models of the upwelling phenomena are related to areas rich of phytoplankton nutrients where a high concentration of pelagic fish is expected.
    Work partly supported in the framework of the project “Sustainable Fishery", funded by Apulia Region – Italy (FEP 2007-2013 - Measure 3.1) aimed at the development of a near-real-time fishery forecasting system in the Adriatic Sea based on satellite data. In-situ data of the 2013 and 2014 fishing seasons were provided by FEDERPESCA (Federazione Nazionale delle Imprese di Pesca). The authors wish to thank Dr. Luigi Giannini of FEDERPESCA and Guido Pasquariello of CNR ISSIA for interesting discussions that further stimulated the improvement of the FiFoS system.

  • [Nit.SPIE2016] D. O. Nitti, A. Morea, R. Nutricato, M. T. Chiaradia, C. La Mantia, L. Agrimano, S. Samarelli, "Automatic GCP extraction with high resolution COSMO-SkyMed products", Proc. SPIE 10003, SAR Image Analysis, Modeling, and Techniques XVI, 1000302 (October 18, 2016), 12 pages; ISBN: 9781510604100. doi:10.1117/12.2241281
    High-resolution Synthetic Aperture Radar (SAR) data represent an essential resource for the extraction of Ground Control Points (GCP) with sub-metric accuracy without in situ measurement campaigns. Conceptually, SAR-based GCP extraction consists of the following two steps: (i) identification of the same local feature on more SAR images and determination of their range/azimuth coordinates; (ii) spatial 3D positioning retrieval from the 2D radar coordinates, through spatial triangulation (stereo analysis) and inversion methods. In order to boost the geolocation accuracy, SAR images must be acquired from different line of sights, with intersection angles typically wider than 10 degrees, or even in opposite looking directions. In the present study, we present an algorithm specifically designed for ensuring robustness and accuracy in the fully automatic detection of bright isolated targets (steel light poles or towers) even when dealing with opposite looking data takes. In particular, the popular Harris algorithm has been selected as detector because it is the most stable and robust-to-noise algorithm for corners detection on SAR images. We outline the designed algorithmic solution and discusses the results derived over the urban area of Pisa (Italy), where more than ten COSMO-SkyMed Enhanced Spotlight (ES) stereo images are available, thus resulting an optimal test site for an assessment of the performances of the processing chain. The experimental analysis proofs that, assumed timing has been properly recalibrated, we are capable to automatically extract GCP from CSK ES data takes consisting in a very limited number of images.
    Study carried out in the framework of the 3D IMINT project (PRNM Contract n.10444, 30-12-2013). CSK® Products, © of the Italian Space Agency (ASI), delivered by ASI under a license to use.

  • [Nut.SPIE2016] R. Nutricato, A. Morea, D. O. Nitti, C. La Mantia, L. Agrimano, S. Samarelli, M. T. Chiaradia, "Automatic SAR/optical cross-matching for GCP monograph generation", Proc. SPIE 10003, SAR Image Analysis, Modeling, and Techniques XVI, 1000303 (October 18, 2016), 8 pages; ISBN: 9781510604100. doi:10.1117/12.2241284
    Ground Control Points (GCP), automatically extracted from Synthetic Aperture Radar (SAR) images through 3D stereo analysis, can be effectively exploited for an automatic orthorectification of optical imagery if they can be robustly located in the basic optical images. The present study outlines a SAR/Optical cross-matching procedure that allows a robust alignment of radar and optical images, and consequently to derive automatically the corresponding sub-pixel position of the GCPs in the optical image in input, expressed as fractional pixel/line image coordinates. The cross-matching in performed in two subsequent steps, in order to gradually gather a better precision. The first step is based on the Mutual Information (MI) maximization between optical and SAR chips while the last one uses the Normalized Cross-Correlation as similarity metric. This work outlines the designed algorithmic solution and discusses the results derived over the urban area of Pisa (Italy), where more than ten COSMO-SkyMed Enhanced Spotlight stereo images with different beams and passes are available. The experimental analysis involves different satellite images, in order to evaluate the performances of the algorithm w.r.t. the optical spatial resolution. An assessment of the performances of the algorithm has been carried out, and errors are computed by measuring the distance between the GCP pixel/line position in the optical image, automatically estimated by the tool, and the “true” position of the GCP, visually identified by an expert user in the optical images.
    Study carried out in the framework of the 3D IMINT project (PRNM Contract n.10444, 30-12-2013). CSK® Products, © of the Italian Space Agency (ASI), delivered by ASI under a license to use.

  • [Sam.SPIE2016] S. Samarelli, A. P. Lorusso, L. Agrimano, R. Nutricato, F. Bovenga, D. O. Nitti, M. T. Chiaradia, "Rheticus: an automatic cloud-based geo-information service platform for territorial monitoring", Proc. SPIE 10003, SAR Image Analysis, Modeling, and Techniques XVI, 100030M (October 18, 2016), 7 pages; ISBN: 9781510604100. doi: 10.1117/12.2241285
    Rheticus® is an innovative cloud-based data and services hub able to deliver Earth Observation added-value products through automatic complex processes and, if appropriate, a minimum interaction with human operators. In this paper, we outlines the capabilities of the “Rheticus® Displacement” service, designed for geohazard and infrastructure monitoring through Multi-Temporal SAR Interferometry techniques.
    Rheticus® is a registered trademark of Planetek Italia srl. The research is partly co-funded by the Italian Space Agency in the framework of the FAST4MAP project (“Fast & Advanced SAR Techniques for Monitoring & Alerting Processes” - ASI Contract n. 2015-020-R.0). Sentinel-1A products provided by ESA. ERS products delivered by ESA under CAT-1 project n. 32017. CSK® Products, © ASI, provided by ASI under a license to use. The computational work has been executed on the IT resources made available by ReCaS, a project financed by the MIUR under “PON R&C 2007-2013” (PONa3_00052).

Conference Abstracts

  • [Was.EGU2016] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti, M. T. Chiaradia, A. Refice and G. Pasquariello, "Exploring the potential of Sentinel-1 data for regional scale slope instability detection using multi-temporal interferometry", Abstracts proceedings EGU 2016, Vienna, Austria, 17-22 April 2016. Abstract ID-No: EGU2016-12505. Vol. 18, eISSN: 1607-7962. URL: http://meetingorganizer.copernicus.org/EGU2016/EGU2016-12505.pdf
    Launched in 2014, the European Space Agency (ESA) Sentinel-1 satellite carrying a medium resolution (20 m) C-Band Synthetic Aperture Radar (SAR) sensor holds much promise for new applications of multi-temporal interferometry (MTI) in landslide assessment. Specifically, the regularity of acquisitions, timeliness of data delivery, shorter repeat cycle (currently 12 days with Sentinel-1A sensor), and flexible incidence angle geometry, all imply better practical utility of MTI relying on Sentinel-1 with respect to MTI based on data from earlier ESA’s satellite radar C-band sensors (ERS1/2, ENVISAT). Furthermore, the upcoming launch of Sentinel-1B will cut down the repeat cycle to 6 days, thereby further improving temporal coherence and quality and coverage of MTI products. Taking advantage of the Interferometric Wide (IW) Swath acquisition mode of Sentinel-1 (images covering a 250 km swath on the ground), in this work we test the potential of such data for regional scale slope instability detection through MTI. Our test area includes the landslide-prone Apennine Mountains of Southern Italy. We rely on over 30 Sentinel-1 images, most of which acquired in 2015, and MTI processing through the SPINUA algorithm (Stable Points INterferometry in Un-urbanized Areas). The potential of MTI results based on Sentinel-1 data is assessed by comparing the detected ground surface displacements with the MTI results obtained for the same test area using the C-Band data acquired by ERS1/2 and ENVISAT in 1990s and 2000s. Although the initial results are encouraging, it seems evident that longer-term (few years) acquisitions of Sentinel-1 are necessary to reliably detect some extremely slow movements, which were observed in the last two decades and are likely to be still present in peri-urban areas of many hilltop towns in the Apennine Mts. The MTI results obtained from Sentinel-1 data are also locally compared with the MTI outcomes based on the high resolution (3 m) TerraSAR-X imagery. Again, even though there is lack of temporal overlap in the two datasets, the comparison shows some potential benefits of the exploitation different resolution sensor datasets. For example, when considering the costs of MTI applications, an effective approach to slope hazard assessment could rely on the use of coarser imagery MTI to secure long-term wide-area coverage, to be integrated by higher resolution MTI with more focus on urbanized or greater value areas (cf., Wasowski and Bovenga et al., 2014a,b). Now these approaches are facilitated by the regular global coverage and free medium resolution imagery guaranteed by the background satellite radar mission of Sentinel-1.
    Study carried out in the framework of the Apulia Space project (PON&REC 2007-2013, Cod: PON03PE_00067_6). We also thank ESA and the German Space Agency (DLR) for providing us radar data.

  • [Chi.AGU2016] M. T. Chiaradia, S. Samarelli, L. Agrimano, A. P. Lorusso, R. Nutricato, D. O. Nitti, A. Morea, K. Tijani, "Rheticus Displacement: an Automatic Geo-Information Service Platform for Ground Instabilities Detection and Monitoring", AGU Fall Meeting 2016, Abstract ID:155327, Poster Presentation G23A-1039, San Francisco, California, USA, 12-16 December 2016.
    Rheticus® is an innovative cloud-based data and services hub able to deliver Earth Observation added-value products through automatic complex processes and a minimum interaction with human operators. This target is achieved by means of programmable components working as different software layers in a modern enterprise system which relies on SOA (service-oriented-architecture) model. Due to its architecture, where every functionality is well defined and encapsulated in a standalone component, Rheticus is potentially highly scalable and distributable allowing different configurations depending on the user needs. Rheticus offers a portfolio of services, ranging from the detection and monitoring of geohazards and infrastructural instabilities, to marine water quality monitoring, wildfires detection or land cover monitoring. In this work, we outline the overall cloud-based platform and focus on the “Rheticus Displacement” service, aimed at providing accurate information to monitor movements occurring across landslide features or structural instabilities that could affect buildings or infrastructures. Using Sentinel-1 (S1) open data images and Multi-Temporal SAR Interferometry techniques (i.e., SPINUA), the service is complementary to traditional survey methods, providing a long-term solution to slope instability monitoring. Rheticus automatically browses and accesses (on a weekly basis) the products of the rolling archive of ESA S1 Scientific Data Hub; S1 data are then handled by a mature running processing chain, which is responsible of producing displacement maps immediately usable to measure with sub-centimetric precision movements of coherent points. Examples are provided, concerning the automatic displacement map generation process, as well as the integration of point and distributed scatterers, the integration of multi-sensors displacement maps (e.g., Sentinel-1 IW and COSMO-SkyMed HIMAGE), the combination of displacement rate maps acquired along both ascending and descending passes.
    Study carried out in the framework of the FAST4MAP project and co-funded by the Italian Space Agency (Contract n. 2015-020-R.0). Sentinel-1A products provided by ESA. CSK® Products, © ASI, provided by ASI under a license to use. Rheticus® is a registered trademark of Planetek Italia srl.

Other poster/slideshow presentations

  • [Bov.LSP2016] F. Bovenga, A. Refice, G. Pasquariello, R. Nutricato, D. O. Nitti, J. Wasowski, "Requirements and prospects of landslide analysis through SAR interferometry and recent satellite missions", 2016 European Space Agency Living Planet Symposium, Prague, Czech Republic, 9-13 May 2016. Poster: Paper ID 496. URL: http://lps16.esa.int/files/Contribution496.pdf
    Thanks to the all-weather, day-night capability to detect and measure small ground surface deformations, multi-temporal Synthetic Aperture Radar (SAR) Interferometry (InSAR) techniques are attractive for landslide investigations. This Multi-temporal InSAR (MTI) application poses challenges related to the limited spatial extent of the phenomenon, the complexity of the ground deformations, and the occurrence in mountainous and vegetated areas that cause visibility problems. Nowadays, several satellite missions are available providing interferometric SAR data at different wavelengths, spatial resolutions, and revisit time. High-resolution X-Band SAR sensors, such as the COSMO-SkyMed constellation, have recently provided data with spatial resolution reaching metric values, and revisit time up to few days leading to increase the density of the measurable targets as well as to improve the detection of non linear movement. Medium resolution C-band SAR data have been thoroughly exploited in the last two decades thanks to the ERS-1/2, ENVISAT-ASAR and Radarsat missions. A new interesting opportunity is recently provided by Sentinel-1 mission, which has just started to deliver data to the user community. Although the spatial resolution is comparable to previous ESA C-band missions the revisit time is reduced to 12 and 6 days, by considering, respectively, one or two satellites. It is envisioned that by offering regular globe-scale coverage, improved temporal resolution and freely available imagery, Sentinel-1 will guarantee an increasing use of MTI in landslide investigations. These background missions are necessary for long-term, systematic mapping of unstable unstable slopes and regional scale assessment of landslide processes. According to these different SAR space-borne missions, the present work discusses current and future opportunities of MTI applications to slope instability monitoring by addressing, through a simple theoretical model, issues related to slope visibility, sensitivity to ground displacement, coherent target detection, mean velocity precision. In particular a comparative analysis is carried out aimed at investigating specific advantages of different satellite missions with respect to wavelength, resolution, revisit time, and clutter backscatter. According to this analysis, we show that a reliable estimates of the displacement rates are possible in a narrower time span by using X-band than C-band, but Sentinel-1 constellation will improve the performance of C-band. Moreover, for a certain time span the expected velocity STD is better for X-band than for C-band but, again, the Sentinel-1 constellation will improve the performance of C-band. This impacts on the monitoring capabilities in high risk situations by providing results in a shorter time, and allows monitoring mountainous areas during short period avoiding snow coverage, thus maximizing the chance to detect coherent targets. Finally, the work provides examples of multi-sensor and multi-scale slope instability investigations obtained by processing real data from both C-band medium resolution and X-band high resolution SAR data. In particular, the differences between displacement maps in terms number of images, observation time span, number of coherent targets, and estimated displacement precision, are used to support the outcomes of previous model.
    Work supported by the project “APULIA SPACE” (PON03PE_00067_6), PON Ricerca e competitività 2007-2013.

  • [Nit.SPIEnr2016] D. O. Nitti, A. Morea, R. Nutricato, M. T. Chiaradia, C. La Mantia, L. Agrimano, S. Samarelli, "Automatic identification of ground control points in synthetic aperture radar images", Accepted for publication in: SPIE Newsroom 2016, DOI: 10.1117/2.1201609.006714
    A new robust tool has been successfully tested on remotely sensed satellite data and can be used to estimate the 3D position of targets, with sub-metric accuracy
    This study is carried out within the framework of the 3D IMINT project (PRNM Contract 10444, 30-12-2013). CSK products, under a license from the Italian Space Agency, were used for this project.

Peer-Reviewed Journal Articles

  • [Nit.Sensors2015] D. O. Nitti, F. Bovenga, M. T. Chiaradia, M. Greco and G. Pinelli, "Feasibility of Using Synthetic Aperture Radar to Aid UAV Navigation", Sensors 2015, vol. 15, pp. 18334-18359; EISSN 1424-8220. Scopus: 2-s2.0-84938267144. doi:10.3390/s150818334. IF: 2.80 (Year: 2015 - Source: https://goo.gl/iI4kfI)
    This study explores the potential of Synthetic Aperture Radar (SAR) to aid Unmanned Aerial Vehicle (UAV) navigation when Inertial Navigation System (INS) measurements are not accurate enough to eliminate drifts from a planned trajectory. This problem can affect medium-altitude long-endurance (MALE) UAV class, which permits heavy and wide payloads (as required by SAR) and flights for thousands of kilometres accumulating large drifts. The basic idea is to infer position and attitude of an aerial platform by inspecting both amplitude and phase of SAR images acquired onboard. For the amplitude-based approach, the system navigation corrections are obtained by matching the actual coordinates of ground landmarks with those automatically extracted from the SAR image. When the use of SAR amplitude is unfeasible, the phase content can be exploited through SAR interferometry by using a reference Digital Terrain Model (DTM). A feasibility analysis was carried out to derive system requirements by exploring both radiometric and geometric parameters of the acquisition setting. We showed that MALE UAV, specific commercial navigation sensors and SAR systems, typical landmark position accuracy and classes, and available DTMs lead to estimated UAV coordinates with errors bounded within ±12 m, thus making feasible the proposed SAR-based backup system.
    The authors acknowledge the support of the SARINA project A-0932-RT-GC, which is coordinated by the European Defence Agency (EDA) and partially funded by 10 contributing Members (Cyprus, France, Germany, Greece, Hungary, Italy, Norway, Poland, Slovakia, Slovenia and Spain) in the framework of the Joint Investment Programme on Innovative Concepts and Emerging Technologies (JIP-ICET).

Book Chapters

  • [Was.IAEG2014] J. Wasowski, F. Bovenga, A. Refice, D. O. Nitti, R. Nutricato, "High Resolution PSI For Mapping Ground Deformations And Infrastructure Instability". Proceedings of the IAEG XII congress, Turin, Italy, 15-19 September 2014. In Book: G. Lollino et al. (eds.), Engineering Geology for Society and Territory – Volume 2, Springer International Publishing Switzerland 2015. ISBN:978-3-319-09057-3; 978-3-319-09056-6. Scopus: 2-s2.0-84944618574. WOS:000358988100063. DOI: 10.1007/978-3-319-09057-3_63.
    Persistent scatterers interferometry (PSI) techniques based on space-borne radar data can provide thousands km2 coverage and precise (mm resolution), spatially dense measurements (from hundreds to over thousands points/km2) on ground surface deformations and infrastructure instability. Furthermore, the practical applicability of PSI is now improved thanks to the increased data availability from ra-dar satellites and the better capabilities of the new space radar sensors (Cosmo-SkyMed, TerraSAR-X) in terms of resolution (from ~3 to 1 m) and revisit time (from 11 to 4 days). Here we compare results from medium and high resolution PSI investigations of subsidence, slope and associated infrastructure instability in two areas with different geo-environmental characteristics in order to illustrate i) the potential in providing valuable site-specific information, ii) the advantages in using high resolution radar data. We also focus on significant technical and interpretation issues in PSI applications and offer specific user guidelines, with emphasis on the benefits resulting from the exploitation of new generation radar sensors.
    ERS-1/2 and TSX data over Wieliczka provided, respectively, by the European Space Agency (ESA) under ALOS ADEN 3595 project and by DLR under TerraSAR-X General AO Project ID MTH0432. CSK images over Haiti provided by the Italian Space Agency (ASI) in the framework of a scientific collaboration between the Centre National de l'Information Géo-Spatiale (CNIGS) of Haiti and the Department of Physics (DIF) of the University of Bari, Italy. CSK images over Calabria region provided by ASI in the framework of the project “Landslide Monitoring and Mapping System - CAR-SLIDE” (PON 01 00536). ENVISAT and TSX data over Pietramontecorvino provided, respectively, by ESA under CAT-1 project ID 2653 and by DLR under TerraSAR-X General AO Project ID MTH0432. Optical images provided by GoogleEarthTM.

International Conference Proceedings

  • [Gue.EESMS2015] A. Guerriero, F. Giuliani, D. O. Nitti, "Crowdsourcing And Mobile Device For Wide Areas Monitoring", Proceedings of the 2015 IEEE Workshop on Environmental, Energy and Structural Monitoring Systems, 9-10 July 2015, Trento, Italy. Electronic ISBN: 978-1-4799-8215-8. CD-ROM ISBN: 978-1-4799-8214-1. Scopus: 2-s2.0-84950983172. DOI: 10.1109/EESMS.2015.7175847
    This paper presents the architecture of an extended areas monitoring system based on crowdsourcing and mobile devices. In particular areas (i.e. very large historical site) it can be difficult or impossible to install fixed cameras due mainly to the huge number of candidate points of interest (POI) to monitoring or to the significant impact on site (i.e. cameras or other sensors could be too invasive towards historic walls or ancient materials). For these sites we propose a system based on a distribute architecture, a server that runs change detection algorithms and clients that run on visitors’ smartphones and assists the acquisition of new pictures comparable to reference photos of the monitored areas. Server contains geo-referenced images of the POI and can automatically add new images of the same POI under partly different observation conditions (like angle of view or light or shadows distribution). The client section, the app on the mobile devices, shows all the POI in the neighboring area of the user, provides a map to reach a selected POI, compares in real time the reference photo of the POI provided by the server with the live view of the smartphone camera and supplies the user directions to obtain the correct overlap of the images.
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  • [Gue.IGARSS2015] A. Guerriero, V. W. Anelli, A. Pagliara, R. Nutricato, D. O. Nitti, "Efficient implementation of InSAR time-consuming algorithm kernels on GPU environment", Proceedings of 2015 IGARSS - International Geoscience and Remote Sensing Symposium, Milano, Italia, 26-31 July 2015 . Electronic ISBN: 978-1-4799-7929-5. USB ISBN: 978-1-4799-7928-8. Print ISSN: 2153-6996. Electronic ISSN: 2153-7003. Scopus: 2-s2.0-84962599944. WOS:000371696704087. DOI: 10.1109/IGARSS.2015.7326768
    Satellite remote sensing radar technologies provide powerful tools for geohazard monitoring and risk management at synoptic scale. In particular, advanced Multi-Temporal SAR Interferometric algorithms are capable to detect ground deformations and structural instabilities with millimetric precision, but impose strong requirements in terms of hardware re-sources. Recent advances in GPU computing and programming hold promise for time efficient implementation of imaging algorithms, thus enhancing the development of advanced Emergency Management Services based on Earth Observation technologies. In this study, a preliminary assessment of the potentials of GPU processing is carried out, by comparing CPU (single- and multi-thread) and GPU implementations of InSAR time-consuming algorithm kernels. In particular, it is focused on the fine coregistration of SAR interferometric pairs, a crucial step in the interferogram generation process. Experimental results are discussed.
    ASAR images made freely available by ESA (dataset SAR Italy EQ April 2009). The authors thank Ferrara Fabio, Lippolis Paola and Saponaro Pierpaolo for their contribution on the OpenMP implementation.

  • [Nit.SPIE2015] D. O. Nitti, R. Nutricato, R. Lorusso, N. Lombardi, F. Bovenga, M. F. Bruno, M. T. Chiaradia, G. Milillo, "On the geolocation accuracy of COSMO-SkyMed products", Proc. SPIE 9642, SAR Image Analysis, Modeling, and Techniques XV, 96420D (15 October 2015); ISBN: 9781628418521. Scopus: 2-s2.0-84961653912. DOI: 10.1117/12.2196870
    Many factors impact on the geolocation accuracy of Synthetic Aperture Radar (SAR) products. The improper Atmospheric Path Delay (APD), orbital errors and timing inaccuracies hinder sub-pixel geolocation accuracy, in particular for radar images acquired by the high resolution X-band side-looking SAR satellite constellations, TerraSAR-X (TSX) and COSMO-SkyMED (CSK). Many scientific studies in the recent literature have demonstrated the suitability of TSX data for sub-decimetre level ranging accuracy without the use of ground control points (GCP, provided APD is properly estimated and corrected for. This is due to the high degree of orbital accuracy of the TSX satellites (the so-called science orbit is in an accuracy range of few centimetres and its very precise radar beam tracing. On the contrary, no definitive results are reported yet in the scientific literature, concerning the best performances achievable by the CSK constellation in terms of geolocation accuracy. Preliminary studies have shown that sub-metric geolocation accuracies are hardly achievable with CSK data, and that APD compensation leads unexpectedly to a worsening of the results (with geolocation errors amounting even to several meters along the slant range direction). Two possible explanations were suggested: (1) a nominal, undocumented APD correction is incorporated into the CSK delivered timing annotations during sampling window start time (SWST) bias calibration, or (2) no APD correction has been implemented in the CSK delivered data, but the annotated range SWST bias is incorrect by several meters (implying the need for re-calibration). These results are in line with the conclusions of other independent studies. The aim of the present work is to further investigate the origin of the geolocation error sources in CSK products. The area surrounding Carlantino town in Daunia region (Southern Italy), has been selected for this study, thanks to the availability of six trihedral corner reflectors (CR) recently installed in the western slope, facing the Occhito lake. The geolocation of CR phase centers is surveyed with cm-level accuracy using differential GPS. A consistent number of CSK HIMAGE stripmap and enhanced spotlight data takes is available over the area of interest. The experimental analysis includes the evaluation of the geolocation accuracy of both SCS and GTC products. Concerning SCS data, the performances of the official ASI processors are compared to those achievable by alternative promising focusing algorithms, for both stripmap and spotlight modes. APD compensation is performed by using the Regional Atmospheric Modelling System (RAMS), a Numerical Weather Prediction model already reliably used for this purpose in previous. The analysis is also extended to the cross-comparison of I-CUGS GTC products with those generated by internal geocoding tools.
    Project carried out using CSK® Products, © of the Italian Space Agency(ASI), delivered under a license to use by ASI.

  • [Nut.IGARSS2015] R. Nutricato, D. O. Nitti, F. Bovenga, A. Refice, J. Wasowski, M. T. Chiaradia, G. Milillo, "COSMO-SkyMED multi-temporal SAR interferometry over Liguria region for environmental monitoring and risk management", Proceedings of 2015 IGARSS - International Geoscience and Remote Sensing Symposium, Milano, Italia, 26-31 July 2015 . Electronic ISBN: 978-1-4799-7929-5. USB ISBN: 978-1-4799-7928-8. Print ISSN: 2153-6996. Electronic ISSN: 2153-7003. Scopus: 2-s2.0-84962529299. WOS:000371696701131. DOI: 10.1109/IGARSS.2015.7326040
    Thanks to the technological maturity as well as to the wide availability of SAR data, Multi-temporal SAR Interferometry (MTInSAR) can be used to support systems devoted to environmental monitoring and risk management. In particular, high resolution X-band MTInSAR applications are also suitable for monitoring single man-made structures (buildings, bridges, railways and highways). The paper presents examples concerning the application of MTInSAR techniques and COSMO-SkyMed constellation for instability monitoring of infrastructures and, in particular, harbor docks and railways.
    Work supported by the projects “CAR-SLIDE -Mapping and monitoring system for landslides forecast” (PON R&C 2007-2013) and “ADF - Archiving Data Fusion” (Second ASI Call dedicated to SMEs), and in the framework of the collaboration between Geophysical Applications Processing Ltd and the Physics Department of Bari with CIDOT (Centro di Eccellenza di Interpretazione Dati di Osservazione della Terra - ASI Matera). CSK products processed under a license of ASI "Original COSMOSkyMed Product - Agenzia Spaziale Italiana - (2013-2014). All rights reserved".

  • [Tij.IGARSS2015] K. Tijani, M. T. Chiaradia, A. Morea, R. Nutricato, L. Guerriero, G.Pasquariello, "Fishing forecasting system in Adriatic sea - a model approach based on a normalized scalar product of the SST gradient and CHL gradient vectors". Proceedings of 2015 IGARSS - International Geoscience and Remote Sensing Symposium, Milano, Italia, 26-31 July 2015 . Electronic ISBN: 978-1-4799-7929-5. USB ISBN: 978-1-4799-7928-8. Print ISSN: 2153-6996. Electronic ISSN: 2153-7003. WOS:000371696702089. Scopus: 2-s2.0-84962571879.DOI: 10.1109/IGARSS.2015.7326256
    By mapping the concentration of chlorophyll-a (CHL) and the temperature of the sea surface (SST), satellite images reveal the complex dynamics of marine waters and prove to be a very powerful tool when used to detect potential fishing areas, significantly reducing the time of the search, the fuel consumption and the human effort, and simultaneously increasing the CPUE (catch per unit effort). In the present work, various techniques of multi-sensor, multi-resolution and multi-temporal data fusion are applied to multi-spectral satellite image data of MODIS-AQUA, MODIS-TERRA and VIIRS sensors, in order to detect "fronts" of chlorophyll concentration and temperature on the sea surface. According to the physical model of the phenomena, these fronts are generated by the upwelling of cold waters rich of nutrients (phytoplankton) which correspond to areas with a high concentration of pelagic fish and are characterized by high values of local gradients of SST and CHL with anti-parallel orientation. An automatic procedure has been developed to calibrate and validate the production in near-real time of daily maps of expected good fishing grounds to be provided to the FEDERPESCA fleet. The same procedure could be optimized also for other seas.
    Work funded by Apulia Region, in the framework of the project "Sustainable Fishery" (FEP 2007-2013 – Measure3.1).

  • [Was.ARS2015] J. WASOWSKI, F. BOVENGA, R. NUTRICATO, D. O. NITTI, M. T. CHIARADIA, S. KUCAJ and B. STRATI, "High resolution satellite multi-temporal interferometry for detecting and monitoring landslide and subsidence hazards", ARS 2015 - 10th Regional Asian Conference of IAEG in Kyoto, 26-27 September 2015, Japan, Kyoto. URL: http://www.jseg.or.jp/2015ARC/data/PaperofInvited/Wasowski_et_al.pdf
    With the increasing number of radar satellites and improved data processing tools, multi-temporal interferometry (MTI) can considerably enhance our capabilities of monitoring landslide and subsidence hazards. MTI provides long-term (years), regular (weekly-monthly), precise (mm) measurements of ground displacements over large areas (thousands of km2), combined with high spatial resolution (up to 1-3 m) and possibility of multi-scale (regional to site-specific) investigations using the same series of radar images. To highlight the great potential of high resolution MTI we discuss application examples from two seismically active regions prone to land instability: i) Albania, including the large plain area occupied by the city of Tirana and nearby scarcely populated mountains, and ii) Haiti, including the Port-au-Prince metropolitan area, with coastal and mountain zones destabilized by the 2010 Mw 7.0 earthquake. It is shown that MTI can provide very useful results in a wide range of geomorphic, climatic and vegetation environments.
    Project carried out using CSK® Products, © of the Italian Space Agency(ASI), delivered under a license to use by ASI. The data for Albania were obtained within the project "Studio su instabilità del terreno sull’area di Tirana (Albania)”. We thank the colleagues of the Centre National dell'Information Géo-Spatiale - CNIGS, Haiti for help in acquiring thematic data and the assistance in the field.

  • [Was.Geomorphometry2015] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti, M. T. Chiaradia, L. Guerriero, "High resolution satellite SAR multi-temporal interferometry for regional scale detection of landslide and subsidence hazards", Proceedings of Geomorphometry 2015, Poznan, Poland, June 22-26, 2015. In: Geomorphometry for Geosciences, Jasiewicz J., Zwolinski Zb., Mitasova H., Hengl T. (eds), pp. 181-184, 2015. Publisher: Publisher Bogucki Wydawnictwo Naukowe, Adam Mickiewicz University in Poznan - Institute of Geoecology and Geoinformation, Poznan, Poland. ISBN: 978-83-7986-059-3. URL: http://geomorphometry.org/system/files/Wasowski2015geomorphometry.pdf
    Among a number of advanced satellite-based remote sensing techniques, synthetic aperture radar (SAR) multi-temporal interferometry (MTI) appears the most promising for fostering new opportunities in landslide and subsidence hazards detection and assessment. MTI is attractive to those concerned with terrain instability hazards because it can provide very precise quantitative information on slow displacements of the ground surface over huge areas with limited vegetation cover. Although MTI is a mature technique, we are only beginning to realize the benefits of the high-resolution imagery that is currently acquired by the new generation radar satellites (e.g., COSMO-SkyMed, TerraSAR-X). In this work we demonstrate the great potential of high resolution MTI for regular, wide-area detection of ground instability hazards by presenting results from two regions characterized by different geomorphic, climatic and vegetation conditions: densely populated metropolitan area of Port-au-Prince (Haiti), with the coastal areas and local slopes destabilized by the 2010 Mw 7.0 earthquake, and the remote high mountain region of Southern Gansu Province (China) prone to large slope failures. The interpretation and widespread exploitation of high spatio-temporal resolution MTI results can be facilitated by visualizing the scientific data using Google Earth TM tools or other web-based applications.
    The Italian Spatial Agency (ASI) provided CSK imagery of China (AO Project ID 1820) and of Haiti (collaboration between the Centre National dell'Information Géo-Spatiale -CNIGS, Haiti and the Department of Physics of the Politecnico di Bari, Italy). We also thank three reviewers for helpful comments.

  • [WAS.EGNM2015] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti and M. T. Chiaradia, "Advanced Satellite Interferometry for Monitoring Road and Railway Infrastructure in Landslide-Prone Areas", Proceedings of the International Conference on Engineering Geology in New Millennium, At Indian Institute of Technology, New Delhi, India. In Volume: Special Publication Journal of Engineering Geology, October 2015, pp. 1349-1359. ISSN: 0970-5317.
    Roads and railways are exposed to instability and damage in landslide-prone areas. While conventional ground-based techniques are too costly for regular, wide-area monitoring of unstable slopes and transpor-tation infrastructure, satellite multi-temporal interferometry (MTI) can now effectively assist in hazard assessment thanks to the improved temporal (days-weeks) and spatial resolutions (1-3 m) of the new satellite radar sensors. The most important strengths of MTI are i) wide-area coverage (up to tens of thou-sands km2) combined with high spatial resolution (meters) and precision of ground surface displacement measurements (mm-cm) and ii) regular, long-term (years) data acquisition with short revisit times (weeks to days) and the availability of long time series of data (since 1992). These strengths offer flexibility to MTI applications such as the possibility of using the same series of images for various scale hazard as-sessments (from regional to local). Importantly, engineering structure response to ground motion can be investigated at high spatial-temporal resolutions over large areas by using the new radar satellites (e.g., the Italian constellation COSMO-SkyMed; the German TerraSAR-X). To highlight the potential of MTI for monitoring transportation infrastructure stability in landslide-prone areas we present regional to local scale case study examples of MTI applications in Italy.
    Work supported in part by Apulia Region in the framework of the project “FRANE PUGLIA ­Rilevamento di deformazioni al suolo con tecniche satellitari avanzate”, with TSX data provided by DLR within the TerraSAR-X General AO Projects MTH0432, and by the CAR-SLIDE project funded by MIUR (PON01_00536), with CSK® Prod-ucts© of the Italian Space Agency (ASI) delivered by ASI under a license to use.

  • [Was.SMPR2015] Wasowski, J., Bovenga, F., Nutricato, R., Nitti, D. O., and Chiaradia, M. T., "APPLICATIONS OF MEDIUM C-BAND AND HIGH RESOLUTION X-BAND MULTITEMPORAL INTERFEROMETRY IN LANDSLIDE INVESTIGATIONS", Proceedings of SMPR 2015 (Sensors and Models in Photogrammetry and Remote Sensing), ISPRS, 3rd International Conference on Geo-information Modeling and Environmental Monitoring, 23–25 November 2015, Kish Island, Iran. In: Int. Arch. Photogramm. Remote Sens. Spatial Inf. Sci., XL-1/W5, pp. 737-743, 2015. ISSN: 2194-9034. WOS:000380618200123. Scopus: 2-s2.0-84974533495. DOI:10.5194/isprsarchives-XL-1-W5-737-2015.
    With the increasing quantity and quality of the imagery available from a growing number of SAR satellites and the improved processing algorithms, multi-temporal interferometry (MTI) is expected to be commonly applied in landslide studies. MTI can now provide long-term (years), regular (weekly-monthly), precise (mm) measurements of ground displacements over large areas (thousands of km2), at medium (~20 m) to high (up to 1-3 m) spatial resolutions, combined with the possibility of multi-scale (regional to local) investigations, using the same series of radar images. We focus on the benefits as well as challenges of multi-sensor and multi-scale investigations by discussing MTI results regarding two landslide prone regions with distinctly different topographic, climatic and vegetation conditions (mountains in Central Albania and Southern Gansu, China), for which C-band (ERS or ENVISAT) and X-band COSMO-SkyMed (CSK) imagery was available (all in Stripmap descending mode). In both cases X-band MTI outperformed C-band MTI by providing more valuable information for the regional to local scale detection of slope deformations and landslide hazard assessment. This is related to the better spatial-temporal resolutions and more suitable incidence angles (40°-30° versus 23°) of CSK data While the use of medium resolution imagery may be appropriate and more cost-effective in reconnaissance or regional scale investigations, high resolution data could be preferentially exploited when focusing on urbanized landslides or potentially unstable slopes in urban/peri-urban areas, and slopes traversed by lifelines and other engineering structures.
    Work carried out using CSK® Products© of the Italian Space Agency (ASI), delivered under a license to use by ASI. CSK imagery for the Chinese and Albanian sites were obtained within the projects, respectively, COSMO-SkyMed AO ID 1820 and “Studio su instabilità del terreno sull’area di Tirana (Albania)”. European Space Agency (ESA) provided ERS and ENVISAT data (CAT-1 C1P2653 Advanced SAR interferometry techniques for landslide warning management). We thank Tom Dijkstra (BGS) and Xingmin Meng (University of Lanzhou) for valuable discussions on geology and landslide processes in Gansu Province, as well as Spartak Kucaj (Polytechnic University of Tirana) for his help within the Albanian project.

Conference Abstracts

  • [Was.EGU2015] J. Wasowski, R. Nutricato, D. O. Nitti, F. Bovenga, M. T. Chiaradia, B. E. Piard and P. Mondesir, "Using high resolution satellite multi-temporal interferometry for landslide hazard detection in tropical environments: the case of Haiti". Abstracts proceedings EGU 2015, Vienna, Austria, 12 - 17 April 2015. Abstract ID-No: EGU2015-13957. Vol. 17, eISSN: 1607-7962.
    Synthetic aperture radar (SAR) multi-temporal interferometry (MTI) is one of the most promising satellite-based remote sensing techniques for fostering new opportunities in landslide hazard detection and assessment. MTI is attractive because it can provide very precise quantitative information on slow slope displacements of the ground surface over huge areas with limited vegetation cover. Although MTI is a mature technique, we are only beginning to realize the benefits of the high-resolution imagery that is currently acquired by the new generation radar satellites (e.g., COSMO-SkyMed, TerraSAR-X). In this work we demonstrate the potential of high resolution X-band MTI for wide-area detection of slope instability hazards even in tropical environments that are typically very harsh (eg. coherence loss) for differential interferometry applications. This is done by presenting an example from the island of Haiti, a tropical region characterized by dense and rapidly growing vegetation, as well as by significant climatic variability (two rainy seasons) with intense precipitation events. Despite the unfavorable setting, MTI processing of nearly 100 COSMO-SkyMed (CSK) mages (2011-2013) resulted in the identification of numerous radar targets even in some rural (inhabited) areas thanks to the high resolution (3 m) of CSK radar imagery, the adoption of a patch wise processing SPINUA approach and the presence of many man-made structures dispersed in heavily vegetated terrain. In particular, the density of the targets resulted suitable for the detection of some deep-seated and shallower landslides, as well as localized, very slow slope deformations. The interpretation and widespread exploitation of high resolution MTI data was facilitated by Google EarthTM tools with the associated high resolution optical imagery. Furthermore, our reconnaissance in situ checks confirmed that MTI results provided useful information on landslides and marginally stable slopes that can represent a considerable hazard to the local population and infrastructure. The case of Haiti suggests that in the future MTI applications can become increasingly more important in cases where little or no conventional monitoring is feasible because of limited funds.
    The Italian Spatial Agency (ASI) provided CSK imagery of Haiti in the framework of a scientific collaboration between the Centre National de l’Information Géo-Spatiale (CNIGS), Haiti and the Department of Physics of the Politecnico di Bari, Italy. We also thank Aldo Giovacchini (Consorzio ITA) and Luciano Guerriero for their help with the project.

  • [Was.Osuwiska2015] J. Wasowski, F. Bovenga, R. Nutricato, D.O. Nitti, M.T. Chiaradia, "Zastosowanie interferometrii satelitarnej o wysokiej rozdzielczosci do monitorowania infrastruktury drogowej i kolejowej w obszarach osuwiskowych". Konferencja Osuwiskowa 2015, Wieliczce, Polska, 19-22 maja 2015.
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  • [Was.GeoBerlin2015] J. Wasowski and F. Bovenga, "Toward better exploitation of satellite multi-temporal interferometry in landslide hazard research". In Wagner, J.; Elger, K. [Eds.] (2014) GeoBerlin2015 - Dynamic Earth from Alfred Wegener to today and beyond - Abstracts. Annual Meeting of DGGV and DMG, 4-7 October 2015. DOI: http://doi.org/10.2312/GFZ.LIS.2015.003
    In situ investigations and monitoring of areas prone to landslides are expensive and limited in terms of spatial and temporal coverage. Therefore, the use of complementary cost-effective remote sensing approaches to slope hazard detection and assessment is an important issue. We solicit a widespread application of satellite multi-temporal interferometry (MTI), an advanced technique that can enhance our capabilities of detecting and monitoring slope hazards. MTI provides long-term (years), regular (weekly-monthly), precise (mm) measurements of ground displacements over large areas (thousands of km2), combined with high spatial resolution (up to 1-3 m) and a possibility of multi-scale (regional to site-specific) investigations using the same series of radar images. Further, the initial reconnaissance approaches relying on medium resolution MTI (e.g. ENVISAT, RADARSAT) can now be suitably integrated with high resolution MTI relying on the new generation radar sensors (e.g. COSMO-SkyMed, TerraSAR-X), thereby providing most valuable information for the spatial and temporal analyses of slope deformation and landslide activity. To highlight the great potential of MTI we present application examples from two seismically active regions prone to land instability. We also stress that MTI results have yet to be fully explored, in particular those based on high spatio-temporal resolution data. Some of the landslide research and application areas that may particularly benefit from MTI include: - Long-term behavior and climatic controls of large, long-lived very slow deep landslides and deep-seated gravitational slope deformations - Post-earthquake landslide activity and evolution of slopes - Early detection and warning of slope instability hazards via long-term monitoring.
    COSMO-SkyMed and TSX data provided, respectively, by the Italian Spatial Agency (ASI) within the COSMO-SkyMed AO Project ID 1820, and by DLR under TerraSAR-X General AO Project ID MTH0432.

  • [Was.ReSyLAB2015] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti, M. T. Chiaradia, "Satellite interferometry for landslide detection in the peri-Adriatic area", Conference: 2nd Regional Symposium on Landslides in the Adriatic-Balkan Region, Belgrade, Serbia, 14-16 May, 2015. Volume: Abolmasov, B. (2015): 2nd Regional Syposium on Landslides in the Adriatic-Balkan Region - Abstracts Proceedings, University of Belgrade, Faculty of Mining and Geology, Belgrade, Serbia, ISBN 978-86-7352-324-8. URL: http://resylab2015.rgf.rs/Predavanja/Invited_Lecturers/INVITED01_Wasowski.pdf
    Advanced multi-temporal interferometry (MTI) techniques are being increasingly used in landslide assessment, as they can provide precise (mm-cm resolution) measurements of very slow ground surface displacements for huge areas with limited vegetation cover. We illustrate the potential of high resolution MTI for wide-area and local-scale detection of slope and associated infrastructure instability hazards in the peri-Adriatic region. This is done by presenting MTI applications to two landslide-prone mountainous areas characterized by different geomorphic, climatic and vegetation conditions, and hence by variable density and distribution of potential radar targets: the eastern-most part of the Southern Apennines and the mountains in central Albania. The results demonstrate that even in such scarcely urbanized areas MTI can provide valuable information on the presence of slope movements that locally affect small human settlements and road network. The gaps in satellite-derived information, especially evident in the more forested Albanian mountains, suggest that MTI could be most profitably exploited in the reconnaissance stage of a slope hazard assessment, to be followed by more detailed investigation and monitoring of sites at risk.
    We thank the Italian (ASI) and German (DLR) space agencies for providing radar satellite imagery. We benefited from the collaboration with Dr. Spartak Kucaj of the Faculty of Geology & Mining Tirana, Albania and from the CSK imagery acquired within the project "Studio su instabilità del terreno sull’area di Tirana (Albania)”.

Other poster/slideshow presentations

  • [Urb.OpenGeoData] V. Urbano, A. Morea, K. Tijani, D. O. Nitti, R. Nutricato, "Open Data satellitari e Sentinel-1: servizi di osservazione della Terra su Cloud", 3° Conferenza OpenGeoData Italia 2015, Sessione "Applicazioni per la pubblicazione ed il riuso dei dati geografici aperti", Roma, 19 Febbraio 2015
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  • [Was.Fringe2015] J. Wasowski, F. Bovenga, R. Nutricato, D. O. Nitti, M. T. Chiaradia, "PSI for landslide hazard assessment and monitoring: current issues, underexploited and future application opportunities", Fringe 2015 Workshop Advances in the Science and Applications of SAR Interferometry and Sentinel-1 InSAR Workshop, Frascati (Rome), Italy, 23-27 March 2015. URL: http://seom.esa.int/fringe2015/page_session24.php#39p
    We discuss current and future opportunities and challenges of PSI applications to slope hazard assessment and monitoring with reference to the recent and upcoming radar satellite launches and the most recent literature (e.g. Bianchini et al., 2014; Wasowski and Bovenga, 2014a,b). In particular, it is envisioned that by offering regular globe-scale coverage, improved temporal resolution (weekly or better) and freely available imagery, new radar satellite missions such as the ESA’s Sentinel-1 will guarantee an ever increasing and more efficient use of PSI in landslide investigations. These background missions are necessary for long-term, systematic mapping of unstable or potentially unstable slopes and regional scale assessment of landslide processes. The initial wide-area (reconnaissance) approaches relying on medium resolution PSI (e.g. ENVISAT, Sentinel-1) can be suitably integrated with high resolution PSI relying on the new radar sensors (e.g. COSMO-SkyMed, TerraSAR-X, RADARSAT-2), thereby providing most valuable information for the spatial and temporal analyses of slope deformation and a sound basis for derived products ranging from individual landslide monitoring to regional hazard identification. The benefits of multi-sensor and multi-scale investigations (from regional to site-specific) are discussed by presenting PSI results concerning two regions (Central Europe and Western China) characterized by distinctly different topographic, climatic and vegetation conditions. It is shown that, with respect to the medium resolution PSI products (based on ERS and ENVISAT imagery in our case studies), the PSI products derived from high resolution imagery (Stripmap COSMO-SkyMed and TerraSAR-X) may not always lead to a significant improvement in terms of detection of unstable slopes or kinematic characterization of active landslides. Therefore, for its most effective use PSI will have to be tailored to the specific region/site conditions, landslide types, depending on the primary objectives of the investigation. For example, in case of critical facilities at risk such as dams or bridges, of urbanized landslides or potentially unstable slopes in urban/peri-urban areas, as well as of slopes traversed by critical lifelines and engineering structures, the cost of acquiring and processing high resolution radar data can easily be justified. Conversely, in wide-area regional investigations, the use of medium resolution imagery will be more appropriate and the most cost-effective. In general, thanks to the improving temporal and spatial resolutions of new generation radar sensors, significant breakthroughs are expected in detailed slope instability process modelling (e.g. kinematic and geotechnical models), as well as in the understanding of spatial and temporal patterns of landslide movement/activity and their relationships to causative or triggering factors (e.g. precipitation, seismic loading). The capability to provide, at regular intervals, long-term ground surface deformation trends offers an unprecedented opportunity for early detection and warning of potential slope instabilities, but further research is needed with focus on the integration of data from PSI and ground-based geotechnical monitoring. We consider this as one of the top applied research priorities. Finally, we stress that PSI-derived results have yet to be fully explored, in particular those based on high spatio-temporal resolution data. Some of the landslide research and application areas that may benefit more from PSI include: (i) Long-term behavior and climatic controls of very slow deeper landslides and deep-seated gravitational slope deformations; (ii) Numerical modeling of very slow persistent landslides and long term evolution of slopes; (iii) Post-earthquake landslide activity and evolution of slopes; (iv) Non-linear kinematics of landslides, maximum velocities and accumulated displacements.
    ENVISAT, COSMO-SkyMed and TSX data were provided, respectively, by ESA under CAT-1 project ID 2653, by the Italian Spatial Agency (ASI) within the COSMO-SkyMed AO Project ID 1820, and by DLR under TerraSAR-X General AO Project ID MTH0432.

  • [Nut.Fringe2015] Nutricato R., Nitti D. O., Bovenga F., Refice A., Wasowski J., Chiaradia M. T., Milillo G., "Exploitation of Multi-Temporal SAR Interferometry for systems devoted to Environmental Monitoring and Risk Management", Fringe 2015 Workshop Advances in the Science and Applications of SAR Interferometry and Sentinel-1 InSAR Workshop, Frascati (Rome), Italy, 23-27 March 2015. URL: http://seom.esa.int/fringe2015/page_session28.php#82p
    Multi-temporal SAR Interferometry (MTInSAR) techniques allow detecting and monitoring millimetric displacements occurring on selected point targets exhibiting coherent radar backscattering properties. Successful applications to different geophysical phenomena have been already demonstrated in literature. During the last several years new application opportunities have emerged thanks to the greater data availability offered by recent launches of radar satellites, and the improved capabilities of the new space radar sensors in terms of both resolution and revisit time. Currently, different space-borne SAR data in L-,C- and X-band are available for InSAR applications. The archived data from the European Space Agency (ESA) missions ERS-1/2 and ENVISAT (ENV) acquired in C-band (about 5 cm of wavelength), at medium resolution (5x20 m2) from 1992 to 2011 make available a large number (more than 40) of images covering more then 10 years with a minimum revisit time of 35 days, which allows performing ground instability analysis back in time almost all over the Earth. ESA Sentilnel-1 constellation will provide the continuity of the C-band SAR operational applications from October 2014. Thanks to the technological maturity as well as to the wide availability of SAR data, MTInSAR can be used to support systems devoted to environmental monitoring and risk management. This work present results obtained in the framework of two projects: the CAR-SLIDE (Mapping and monitoring system for landslides forecast) project which is funded by MIUR (PON R&C 2007-2013) and ADF (Archiving Data Fusion) project, funded by the Italian Space Agency (Second ASI Call dedicated to SMEs). CAR-SLIDE is aimed at implementing an advanced diagnostic system capable to warn of and monitor landslide events along railway networks, by integrating in situ data detected from on board sophisticated innovative measuring systems, with Earth Observation (EO) techniques. In particular SAR interferometry is used to monitor landslide events. The CAR-SLIDE system is structured in a modular way and mainly consists of the following three subsystems (S/S): (1) railway infrastructure monitoring S/S (based on video inspection sensors, georadars, vibration measurement systems and track geometry measuring devices) ; (2) Environmental Monitoring system (based on satellite SAR and optical data, and weather forecast provided by prognostic non-hydrostatic numerical mesoscale models); (3) Support Decision System (SSD). All measurements provided by the respective monitoring systems are integrated into the SSD, with the aim of improving the railway transport security management, by extending the concept of “black-box for alarm generation” to the actual idea of “telemetry for security management”. The goal of the ADF project is to design an innovative system for EO data acquisition, processing, fusion and archiving to support public institutions and private companies involved in emergency management, territorial planning and precise farming. The system has the capability to interface with many EO (SAR and optical) and traditional data sources and archives, thus enabling their selection and processing on demand, and to perform data fusion of EO data with ancillary data (INSPIRE, OpenStreetMap, etc.), with a high level of automatism. Concerning emergency management, data fusion techniques of SAR and optical data, together with land cover maps and digital terrain models are used to provide a priori estimations of Persistent Scatterers density along different line-of-sights, look sides and pass directions. We presents results obtained by processing COSMO-SkyMed satellite data acquired over Calabria region (Southern Italy) and Liguria region (Northern Italy). The first test case shows interesting results concerning the Calabria's Tyrrhenian railway line, classified as fundamental line by the Italian Rail Network and belonging to the Trans-European Transport Network. Moreover, it provides another interesting example of infrastructure monitoring concerning the “Giambarelli” viaduct along the A3 highway close to the Barritteri town. The second example consists in a retrospective analysis on the detection of precursory signals related to the landslide which occurred on January 2014 close to the town of Marina di Andora. The landslide caused the derailment of a train and the interruption of the railway line connecting north-western Italy to France. We show that a cluster of moving targets coincides with the structures (buildings and terraces) affected by the 2014 landslide. The analysis of the MTI time series further shows that the targets had been moving since 2009, and thus could have provided a forewarning signal about ongoing slope or engineering structure instability. Further examples, concerning the suitability of MTInSAR techniques and high-resolution SAR sensors for man-made structures stability over the Genoa metropolitan and surrounding areas, are also presented and discussed.
    Work supported by the projects “Landslide Monitoring and Mapping System - CAR-SLIDE” (PON 01 00536) and “ADF - Archiving Data Fusion” (Second ASI Call dedicated to SMEs). CSK data are provided by ASI (Agenzia Spaziale Italiana) in the framework of CAR-SLIDE and ADF projects and the collaboration between Geophysical Applications Processing - GAP srl and CIDOT (Centro di eccellenza di Interpretazione Dati di Osservazione della Terra – ASI Matera).

  • [Abba.GRSG2015] C. Abbattista, I. Epicoco, F. Macchiac, Francesca Mele, D. O. Nitti, R. Nutricato, "GPU4EO challenge 2015: boosting SAR interferometry", Challenges in Geological Remote Sensing, 9-11 December 2015, ESA ESRIN, Frascati, Italy. URL: https://www.grsg.org.uk/abstracts/gpu4eo-challenge-2015-boosting-sar-interferometry/
    Recent advances in GPU computing and programming hold promise for time efficient implementation of imaging algorithms, thus enhancing the development of advanced Emergency Management Services based on Earth Observation technologies. In the framework of the RIESCO project, Planetek Italia Srl has promoted the GPU4EO Challenge 2015, whose goal was to stimulate the intensive use of GPUs in the field of image processing and more specifically in the field of remote sensing applications, in order to enhance the synergy between research and business. In particular, Synthetic Aperture Radar (SAR) Differential Interferometry is a powerful and consolidated technique for ground displacements detection and geohazard monitoring, but impose strong requirements in terms of hardware resources. To this end, the Delft Object-oriented Radar Interferometric Software (DORIS) was selected as target application. This open source tool, developed by the DEOS Institute of the Delft University of Technology, is specific for the interferometric processing of satellite SAR images and is composed of a number of computing processes to be optimized and ported to GPU platforms, in order to reduce the overall execution time. GPU4EO has been a sprint initiative, from April to mid-June 2015, which involved research teams coming from different Italian universities. A reference hardware platform was provided to all the participants by the ReCaS data center, based on NVIDIA K40 board, for testing the developments and assessing the performance achieved. In this presentation, the most effective results achieved by the winner team, from University of Salento, will be presented. The main issues have been the data dependency within loops, the optimal use of device memory hierarchy, the isolation of the I/O operations and the use of existent optimized numerical library for GPU like cuFFT. The results achieved within the challenge timeframe have been very encouraging, reaching more than 5x of performance improvement.
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  • [Chi.GRSG2015] M. T. Chiaradia, A. Morea, K. Tijani, L. Guerriero, R. Nutricato, D. O. Nitti, G. Pasquariello, F. Bovenga, A. Refice, "Preliminary Analysis of Sentinel-1 IW data for Geohazard Monitoring and Mapping", Challenges in Geological Remote Sensing, 9-11 December 2015, ESA ESRIN, Frascati, Italy.
    SENTINEL-1 (S1) mission has been developed by ESA for the specific priorities of the Copernicus programme. S1 is a constellation of two satellites carrying a C-Band Synthetic Aperture Radar (SAR), designed to provide enhanced revisit frequency, continuous acquisition plan, large-scale coverage (thanks to the innovative IW – Interferometric Wide swath acquisition mode, capable to cover swaths on ground up to 250 km wide), timeliness and reliability, thus enabling the development of advanced Emergency Management Services based on Earth Observation technologies. Preliminary results concerning the use of S1 IW SAR data for geohazard monitoring and mapping are presented in this study. The first example concerns the analysis of the Mexico city test site, subject to strong subsidence (up to 2.5 cm/month) due to ground water extraction from the aquifer located beneath the metropolitan area, and where around 20 VV images have been acquired on ascending passes from October 2014 to date. Ground surface displacements have been measured through the SPINUA processing chain, an advanced Multi-Temporal SAR Interferometric algorithm that has been recently upgraded to support S1 data. A second example concerns the study of an intense flood event occurred on 17 April 17 2015 in Quelimane, as reported by the Namibia Flood Dashboard, by using multi-polarized S1 data acquired just few hours after the rainfall peak. Quelimane is a seaport in Mozambique, close to the river “Rio dos Bons Sinais” and located in a region extremely prone to floods during the rainy season. The mapping of the flooded area is done by comparing the signature of flood water in both VH and VV polarized radar data. The mean backscattering signature profiles of various water bodies is analyzed to discriminate flood water from other water bodies.
    Study carried out in the framework of the Apulia Space project (PON&REC 2007-2013, Cod: PON03PE_00067_6).

  • [Nit.RECAS2015] D. O. Nitti, "Nuove tecnologie per l'analisi di immagini da satellite", Workshop: Il DataCenter ReCaS di Bari, 9 July 2015. URL: https://goo.gl/7Y0TIu
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Peer-Reviewed Journal Articles

  • [Ref.JSTARS2014] A. Refice, D. Capolongo, G. Pasquariello, A. D'Addabbo, F. Bovenga, R. Nutricato, F.P. Lovergine, L. Pietranera, "SAR and InSAR for Flood Monitoring: Examples With COSMO-SkyMed Data". IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, Vol. 7, Issue 10, 2014. ISSN: 1939-1404. Scopus: 2-s2.0-84906948179. WOS:000341568700002. DOI: 10.1109/JSTARS.2014.2305165. IF: 3.97 (Year: 2014 - Source: https://goo.gl/NwmoU1)
    We apply high-resolution, X-band, stripmap COSMO-SkyMed data to the monitoring of flood events in the Basilicata region (Southern Italy), where multitemporal datasets are available with short spatial and temporal baselines, allowing interferometric (InSAR) processing. We show how the use of the interferometric coherence information can help to detect more precisely the areas affected by the flood, reducing false alarms and missed identifications which affect algorithms based on SAR intensity alone. The effectiveness of using the additional InSAR information layer is illustrated by RGB composites of various combinations of intensity and coherence data. Analysis of multitemporal SAR intensity and coherence trends reveals complex behavior of various field types, which we interpret through a Bayesian inference approach, based on a manual identification of representative scattering and coherence signatures of selected homogeneous fields. The approach allows to integrate external, ancillary information to derive a posteriori probabilistic maps of flood inundation accounting for different scattering responses to the presence of water. First results of this semiautomated methodology, using simple assumptions for the SAR signatures and a priori information based on the distance from river courses, show encouraging results, and open a path to improvement through use of more complex hydrologic and topo-hydrographic information.
    The authors thank the editors and two anonymous reviewers for their comments and suggestions. SAR data were courtesy of e-Geos S.p.A. InSAR processing was performed by Dr. D.O. Nitti of GAP s.r.l.

Book Chapters

  • [Was.WLF2014] J. Wasowski, F. Bovenga, T. Dijkstra, X. Meng, R. Nutricato, and M. T. Chiaradia, "Persistent Scatterers Interferometry provides insight on slope deformations and landslide activity in the mountains of Zhouqu, Gansu, China", World Landslide Forum 2014 (Bejing), in "Landslide Science for a Safer Geoenvironment", K. Sassa et al. (eds.), Vol. 2, pp 359-364. Springer International Publishing Switzerland 2014 ISBN: 978-3-319-05049-2 (Print) 978-3-319-05050-8 (Online). Scopus: 2-s2.0-84905398788. DOI 10.1007/978-3-319-05050-8_56. Proceedings of Third World Landslide Forum (WLF3), Beijing, China, 2–6 June 2014.
    We present the results of Persistent Scatterers Interferometry (PSI) applied to investigate slope instabilities in a remote high mountain region of Southern Gansu, known to be prone to large magnitude (M7-8) earthquakes and catastrophic slope failures. The PSI processing of high resolution (~3 m) COSMO/SkyMed (CSK) satellite images produced spatially dense information (more than 1,000 PS/km2) on ground surface displacements in the area of Zhouqu, a town located in the Bailong River valley. A substantial portion of the radar targets showed significant displacements (from few to over 50 mm/year), denoting widespread occurrence of slope instabilities. In particular, the PSI results provided valuable information on the activity of some very large, apparently slow landslides that represent a persistent hazard to the local population and infrastructure. Monitoring movements of large long-lived landslides is important especially when, as in the case of the Bailong valley, they are known to undergo periods of increased activity resulting in river damming and disastrous flooding. Given the general lack of monitoring data on large landslides at Zhouqu and on other similar major failures that are common in Southern Gansu, the PSI derived displacements offer unique information, which, following expert judgment, can be used for preliminary wide-area assessments of hazards linked to landslide activity. Furthermore, this study shows that with the high resolution CSK data resulting in high radar target density, PSI can also assist in slope/landslide-specific assessments.
    Work supported in part by the Italian Spatial Agency (ASI) - COSMO-SkyMed AO Project ID 1820. COSMO imagery provided by ASI. Special thanks to Dr Jie Gong and Lanzhou University students (Peng Guo, Guan Chen, Yajun Li, Runqiang Zeng, Liang Qiao, Wei Zhou, Haixiao Zhang, Xiaobin Yang) for valuable assistance with fieldwork.

International Conference Proceedings

  • [Nit.EUSAR2014] D. O. Nitti, F. Bovenga, R. Nutricato, A. Refice, M. F. Bruno, A. F. Petrillo, M. T. Chiaradia, "On the use of Numerical Weather Models for improving SAR geolocation accuracy". Proceedings of EuSAR 2014 - 10th European Conference on Synthetic Aperture Radar, Berlin, Germany, 03-05 June 2014, VDE edt., ISBN: 978-3-8007-3607-2. ISSN: 2197-4403 . https://www.vde-verlag.de/proceedings-en/453607109.html
    In order to ensure sub-pixel accuracy of geocoded SAR products, accurate estimation and correction of the Atmospheric Path Delay (APD) is needed, in particular for the new generation of high resolution satellite SAR sensors (TerraSAR-X, COSMO/SkyMED). The present work aims at assessing the performances of operational Numerical Weather Models (NWM) as tools for estimating the APD along the SAR signal acquisition geometry. The Regional Atmospheric Modeling System (RAMS) has been selected for this purpose. In order to guarantee an accurate knowledge of both the satellite orbit and target position, TerraSAR-X data and corner reflectors have been used for the experiment.
    TSX data are provided by DLR (TSX General AO Project MTH0432). CSK data provided by ASI (AO-COSMO Project ID-1462). This work has been partially funded by MIUR (CARSLIDE project, PON01_00536).

  • [Dad.IGARSS2014] A. D’addabbo, A. Refice, G. Pasquariello, F. Bovenga, M. T. Chiaradia, D.O. Nitti, "A Bayesian Network for Flood Detection". Proceedings of 2014 IGARSS - International Geoscience and Remote Sensing Symposium, Québec, Canada, 13-18 July 2014 . ISSN: 2153-6996. eISSN: 2153-7003 . Scopus: 2-s2.0-84911416044. WOS:000349688105041. DOI: 10.1109/IGARSS.2014.6947260
    We apply a Bayesian Network (BN) paradigm to the problem of monitoring flood events through synthetic aperture radar (SAR) and interferometric SAR (InSAR) data. BNs are well-founded statistical tools which help formalizing the information coming from heterogeneous sources, such as remotely sensed images, LiDAR data, and topography. The approach is tested on the fluvial floodplains of the Basilicata region (southern Italy), which have been subject to recurrent flooding events in the last years. Results show maps efficiently representing the different scattering/coherence classes with high accuracy, and also allowing separating the multitemporal dimension of the data, where available. The BN approach proves thus helpful to gain insight into the complex phenomena related to floods, possibly also with respect to comparisons with modeling data.
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  • [Bov.SPIE2014] F. Bovenga, A. Refice, G. Pasquariello, D. O. Nitti, R. Nutricato, "Corner reflectors and multi-temporal SAR inteferometry for landslide monitoring". Proc. SPIE 9243, SAR Image Analysis, Modeling, and Techniques XIV, 92430I (October 21, 2014). Scopus: 2-s2.0-84922682392. WOS:000349373200015. DOI: 10.1117/12.2066833. ISSN 0277-786X.
    The application of Persistent Scatterer Interferometry (PSI) to slope instability monitoring poses challenges related to the complex kinematics of the phenomenon, as well as to the unfavourable settings of the area affected by landslides, often occurring on sites of limited extension, characterized by steep topography and variable vegetation cover. New-generation SAR sensors, such as TerraSAR-X (TSX) thanks to their higher spatial resolution, make PSI applications very promising for monitoring areas with low density man-made. Nevertheless, the application of techniques still remains problematic or impossible in rural and mountainous areas. This is the case, for instance, for the Municipality of Carlantino, in Southern Italy. Both medium resolution SAR data from ESA satellites, and X-band high resolution SAR data from the TSX satellite, were processed through the PSI algorithm SPINUA. Despite the higher spatial density of PS from TSX, the landslide body is lacking coherent targets, due to vegetation and variable land cover. To allow stability monitoring, a network of six CRs was designed and deployed over the landslide test site. Twenty-six TSX stripmap images were processed by using both PSI and an ad hoc procedure based on double-difference analysis of DInSAR phase values on the CR pixels, constrained by the accurate CR height measurements provided by DGPS. Despite the residual noise due to the sub-optimal CR network and the strong atmospheric signal, displacement estimation on the CRs allows to propagate the PSI results downslope, proving the stability of the landslide area subjected to consolidation works.
    Work supported by the Italian Ministry of Research in the framework of PRIN 2008 research grant "Advanced technologies in the assessment and mitigation of the landslide risk: precursors detection, previsional models and thematic mapping". TerraSAR-X data are provided by DLR under TerraSAR-X General AO Project ID MTH0432. PS map on Carlantino from TSX data was obtained by GAP srl in the framework of the Puglia Region project "FRANE PUGLIA - Rilevamento di deformazioni al suolo con tecniche satellitari avanzate". Authors thanks Ing. Pino d’Amelio for supporting the deployment activity.

  • [Con.SPIE2014] D. Conte, F. Bovenga, A. Refice, D. O. Nitti, R. Nutricato, M. T. Chiaradia, "Suitability of COSMO-SkyMed constellation for radargrammetric DEM generation". Proc. SPIE 9243, SAR Image Analysis, Modeling, and Techniques XIV, 924302 (October 21, 2014). DOI: 10.1117/12.2066846. Scopus: 2-s2.0-84922623255. WOS:000349373200001. ISSN 0277-786X.
    The COSMO-SkyMed (CSK) constellation acquires data from its four SAR X-band satellites in several imaging modes, providing in particular different view angles. The present work investigates the potential of CSK constellation for ground elevation measurement through SAR radargrammetry. We selected an area around Parkfield (California), where several CSK acquisitions are available. We used for radargrammetric processing 2 CSK spotlight image pairs acquired at 1 day of separation, in Same Side Viewing configuration, with baselines of 350 km. Furthermore, a dataset of 33 spotlight images were selected to derive height measurements through both persistent scatterers interferometry(PSI) and interferometric processing of 5 1-day separated pairs included in the dataset. We first predict how the errors in the geometrical parameters and the correlation level between the images impact on the height accuracy. Then, two DEMs were derived by processing the radargrammetric CSK pairs. According to the outcomes of the feasibility analysis, processing parameters were chosen in order to guarantee nominal values of height accuracy within the HRTI Level 3 specifications. The products have a final resolution of 3 m. In order to assess the accuracy of these radargrammetric DEMs, we used the height values provided by the PSI, and an interferometric DEM derived from the CSK tandem-like pairs.
    COSMO/SkyMed data used for SAR interferometry are provided by the Italian Space Agency (ASI) in the framework of the AO-COSMO Project ID-1462 "Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation" - ASI Contract I/063/09/0. COSMO/SkyMed data used for radargrammetry are provided by ASI in the framework of D. Conte's PhD research project “Caratterizzazione di bersagli non cooperanti e misure di quota di precisione mediante tecniche interferometriche e radargrammetriche multitemporali con immagini satellitari acquisite dalla costellazione COSMO/SkyMed”. Authors thank Dr. Francesco Nirchio from ASI for his support.

  • [Nut.SPIE2014] R. Nutricato, D. O. Nitti, F. Bovenga, A. Refice, M. T. Chiaradia, "Exploitation of a large COSMO-SkyMed interferometric dataset". Proc. SPIE 9243, SAR Image Analysis, Modeling, and Techniques XIV, 92430C (October 21, 2014). DOI: 10.1117/12.2067156. Scopus: 2-s2.0-84922671767. WOS:000349373200010. ISSN 0277-786X.
    In this work we explored a dataset made by more than 100 images acquired by COSMO-SkyMed (CSK) constellation over the Port-au-Prince (Haiti) metropolitan and surrounding areas that were severely hit by the January 12th, 2010 earthquake. The images were acquired along ascending pass by all the four sensors of the constellation with a mean rate of 1 acquisition/week. This consistent CSK dataset was fully exploited by using the Persistent Scatterer Interferometry algorithm SPINUA with the aim of: i) providing a displacement map of the area; ii) assessing the use of CSK and PSI for ground elevation measurements; iii) exploring the CSK satellite orbital tube in terms of both precision and size. In particular, significant subsidence phenomena were detected affecting river deltas and coastal areas of the Port-au-Prince and Carrefour region, as well as very slow slope movements and local ground instabilities. Ground elevation was also measured on PS targets with resolution of 3m. The density of these measurable targets depends on the ground coverage, and reaches values higher than 4000 PS/km2 over urban areas, while it drops over vegetated areas or along slopes affected by layover and shadow. Heights values were compared with LIDAR data at 1m of resolution collected soon after the 2010 earthquake. Furthermore, by using geocoding procedures and the precise LIDAR data as reference, the orbital errors affecting CSK records were investigated. The results are in line with other recent studies.
    COSMO/SkyMed data provided by the Italian Space Agency (ASI) in the framework of a scientific collaboration between the Centre National de l'Information Géo-Spatiale (CNIGS) of Haiti and the Department of Physics (DIF) of the University of Bari, Italy. LIDAR data were acquired by Rochester Institute of Technology and Kucera International, under sub-contract to ImageCat Inc. and funded by the Global Facility for Disaster Reduction and Recovery (GFDRR) hosted at The World Bank (DOI:10.5069/G96Q1V50). This study was partly funded by the HALL project (“Plasma propulsion system for the growth of Apulian Aerospace Industry”), in the framework of the PO FESR Apulia 2007/2013, Line 1.2, Action 1.2.4.

National Conference Proceedings

  • [Chi.SCORE2014] M. T. Chiaradia, R. Nutricato, D. O. Nitti, K. Tijani, L. Guerriero, F. Ciola, F. Intini, F. Bovenga, A. Refice, G. Pasquariello, J. Wasowski, G. Milillo, "CAR-SLIDE project: integration of EO technologies and diagnostic systems for advanced transport infrastructure monitoring". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2964-6.
    CAR-SLIDE is a MIUR project (PON RandC 2007-2013) aimed to implement an advanced diagnostic system capable to monitor landslide and flood events along the national rail networks, by integrating in situ data detected from on board sophisticated innovative measuring systems, with Earth Observation techniques (based on weather forecast, SAR and optical data). In order to highlight the potential of COSMO/SkyMed satellite data for geohazard detection and mapping, two test cases are presented in this work. The first one consists in the application of multitemporal SAR/InSAR techniques for monitoring recent flood events in the Basilicata region, causing rail service interruptions. The second example consists in a retrospective analysis on the detection of precursory signals related to the landslide which occurred on January 2014 close to the town of Marina di Andora. The landslide caused the derailment of a train and the interruption of the railway line connecting north-western Italy to France.
    Work funded by MIUR (CARSLIDE project, PON01_00536)

  • [Chi.SCORE2014b] M. T. Chiaradia, A. Morea, D. Conte, K. Tijani, G. Preziosa, L. Guerriero, R. Nutricato, D. O. Nitti, F. Ciola, F. Intini, F. Bovenga, A. Refice, G. Pasquariello, J. Wasowski, "Outline of Ongoing Research Activities of the Remote Sensing Group at the Physics Department of Bari". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2965-3.
    The paper outlines the ongoing research activities of the Remote Sensing Group at the Physics Department of Bari in the field of image processing and Earth Observation, and related SW/HW technologies. In the framework of projects founded by national and international space agencies (ASI, ESA, NASA) and the European Community, the group is working in close collaboration with the ISSIA and IRPI institutes of the National Council of Research, in Bari, and Geophysical Applications Processing srl, a POLIBA spinoff company founded in 2006 that represents a valuable example of knowledge transfer from research institutions to industries. Research themes include: (1)development of advanced Multi-Temporal InSAR algorithms for geohazard detection and infrastructure stability analysis; (2)VIS/NIR remote sensing for the health monitoring of marine ecosystems or the detection of fish catch lines; (3)high resolution forecast services using non-hydrostatic NWP models for environmental risk prevention.
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  • [Bru.SCORE2014] M. F. Bruno, B. Nobile, R. Francioso, R. Nutricato, D. O. Nitti, "Effective Coastal Areas Monitoring through COSMO-SkyMed high-resolution radar acquisitions". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2966-0.
    Growing urbanization, human activities and climate changes are worsening shoreline erosion phenomena all around the Italian coasts. This requires a continuous monitoring activity, that is impractical in terms of costs and logistics through traditional in situ investigations over wide scale. Thanks to the all-weather day/night radar imaging capability and to the nationwide acquisition plan named MapItaly, devised by the Italian Space Agency and active since 2010, COSMO-SkyMed constellation is able to provide X-band images covering the Italian territory with a best effort revisit time of 16 days, thus enhancing Integrated Coastal Zone Management through Earth Observation (EO) techniques. The study is focused on the advanced EO system, named COSMO-Beach, designed for semi-automatic shoreline and coastal morphology identification. System features and performances are presented, together with its application on the coastal stretch between towns of Torre Canne and Savelletri (Apulia Region).
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  • [Gue.SCORE2014] A. Guerriero, V. W. Anelli, A. Pagliara, R. Nutricato, D. O. Nitti, "High performance GPU implementation of InSAR time-consuming algorithm kernels". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2967-7.
    Satellite remote sensing radar technologies provide powerful tools for geohazard monitoring and risk management at synoptic scale. In particular, advanced Multi-Temporal Interferometric processing algorithms are capable to detect ground deformations and structural instabilities with millimetric precision, but impose strong requirements in terms of hardware resources. Recent advances in GPU computing and programming hold promise for time efficient implementation of imaging algorithms, thus enhancing the development of advanced Emergency Management Services based on Earth Observation technologies. In this study, a preliminary assessment of the potentials of GPU processing is carried out, by comparing CPU (single- and multi-thread) and GPU implementations of InSAR time-consuming algorithm kernels. In particular, it is focused on the fine coregistration of SAR interferometric pairs, a crucial step in the interferogram generation process. Experimental results are presented and discussed.
    The ENVISAT satellite images were made freely available by ESA (dataset SAR Italy earthquake April 2009).

  • [Chi.SCORE2014t] M. T. Chiaradia, D. Conte, F. Bovenga, A. Refice, L. Guerriero, F. Nirchio, "COSMO-SkyMed constellation capabilities for DEM generation". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2965-3.
    The COSMO/SkyMed (CSK) constellation acquires data from its four SAR X-band satellites in several imaging modes and different view angles. The paper investigates its capabilities for ground elevation measurement through both radargrammetric and interferometric techniques, and evaluates the impact of the improved spatial resolution with respect to the previous SAR sensors. Parkfield (California, USA) has been selected as test site thanks to the availability of consistent dataset of CSK images acquired in both stripmap and spotlight modes. The interferometric analysis shows that, under proper conditions, tandem-like pairs with normal baselines higher than 300 m allow to derive interferometric DEMs fulfilling the HRTI Level 3 standard. SAR radargrammetry is less accurate but more robust than interferometric methods, which can be strongly affected by coherence losses, atmospheric artifacts and phase unwrapping errors. Persistent Scatterers are used as GCPs for the performance assessment.
    This work has been partly funded by the Italian Space Agency in the context of the CRESP project (Cosmo Radar Expert System of Processing), in the framework of the second thematic announcement on "Earth Observation" reserved to SME.

  • [Chi.SCORE2014q] M. T. Chiaradia, L. Guerriero, K. Tijani, A. Morea, F. Ciola, G.Pasquariello, "Fishing Grounds Detection by Satellite Remote Sensing Techniques". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2967-7.
    Quick detection of fishing grounds using satellite based remote sensing techniques can significantly reduce the searching time, the usage of fuel and the human effort and increase the CPUE (Catch per unit effort). Multi-temporal and multi-sensor data fusion techniques have been applied to MODIS-AQUA, MODIS-TERRA and VIIRS multi-spectral data to detect chlorophyll and temperature fronts in the low Adriatic and in the Ionian seas. These fronts are generated by the upwelling of cold waters rich of phytoplankton nutrients where an high concentration of pelagic fish is expected. CPUE data have been provided by the FEDERPESCA fleet relative to the 2013 and 2014 fishing campaigns conducted in the areas of interest. An automatic procedure has been developed to calibrate and validate the production in near-real time of daily maps of expected good fishing grounds to be provided to the FEDERPESCA fleet. The same procedure could be optimized also for other seas.
    Work funded by Apulia Region, in the framework of the project "Sustainable Fishery" (FEP 2007-2013 – Measure 3.1)

  • [Mol.SCORE2014] M. G. Molfetta, A. Morea, G. Preziosa, "A new approach for measuring short water waves through stereo image sequences and artificial markers". First WORKSHOP on the State of the art and Challenges Of Research Efforts @POLIBA (SCORE@POLIBA), December 3-5, 2014, Politecnico di Bari, Italy. ISBN: 978-88-492-2966-0.
    We present an innovative approach to obtain, with a single instrument, measurements of several wave motion parameters of interest in physical models of marine hydraulics. The system, realized and tested in a laboratory environment, is based on stereo computer-vision techniques. A number of colored floating markers with low inertia are evenly distributed in the field of view of two synchronized movie-cameras, whose frame cover large portions of the hydraulic model. Specific computer-vision procedures are implemented to analyze acquired data. The system captures wave data simultaneously in a high number of points of the wave field and overcomes some limitations of the commonly used probes, limited in numbers, more intrusive and in need of frequent calibration. The system achieved good measurement’s accuracy within 5% in terms of significant wave height and 1% in terms of frequency spectrum, in comparison to the traditional calibration probes.
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Conference Abstracts

  • [Was.IGU2014] J. Wasowski, F. Bovenga, R. Nutricato, D.O. Nitti, M.T. Chiaradia, "Satellite multi-temporal interferometry for local and regional scale slope instability and subsidence hazard assessment". 2014 International Geographical Union Regional Conference, Kraków, Poland, 18-22 August 2014. Abstracts IGU2014–0964. http://www.igu2014.org/programme_detailed/pdf/12_gh1/Wasowski_Satellite.pdf
    Satellite multi-temporal interferometry (MTI) is appealing to scientists and end users concerned with ground instability hazards because it can provide very precise information on slow ground surface displacements over vast areas with limited vegetation cover. The outstanding capacities and advantages of MTI applications include: (1) Wide-area coverage (tens of thousands of km2) combined with high spatial resolution (up to 1 m for the new generation radar sensors) and hence the possibility of conducting multi-scale investigations with the same datasets (from regional to site-specific); (2) Systematic, high frequency (from few days to weeks) measurements over long periods (years); (3) High precision of surface displacement measurements (mm-cm resolution) only marginally affected by bad weather conditions; (4) Cost-effective, especially in case of long-term, large area investigations (catchment to regional scale); (5) Integration of monitoring based on new satellite imagery with retrospective studies (using archived imagery) to investigate ground failure history and long-term instability processes (e.g. post-mining subsidence, landslide reactivation); (6) Regional scale, regular update on the persistence (or not) of ground stability conditions in inhabited areas or those to be urbanized (prevention and land use planning). Considering the advantages listed above, we foresee a possibility of future massive exploitation of MTI technology in ground instability hazard assessment. It is also expected that MTI applications could become increasingly more important in cases where little or no conventional monitoring is feasible (e.g. remote locations and limited funds). The main purpose of this work is to illustrate the potential of MTI and explain what kind of information this remote sensing technique can deliver. This is done by presenting case study examples of local to catchment scale MTI applications regarding slope instability and subsidence hazards in areas characterized by a wide range of geomorphic, climatic and vegetation conditions (China, Haiti, Italy and Poland).
    The work has been in part supported by the MORFEO project funded by the Italian Spatial Agency(ASI) (Contract n. I/045/07/0). ASI also provided COSMO-SkyMed imagery of China under AO Project ID 1820, as well as imagery of Haiti in the framework of a scientific collaboration between the Centre National de l'Information Géo-Spatiale (CNIGS), Haiti and the Department of Physics (DIF) of the University of Bari, Italy. ENVISAT and TerraSAR-X data were provided, respectively, by the European Space Agency (ESA) under project ID 2653 and by the German Space Agency (DLR) under TerraSAR General AO Project ID MTH0432.

  • [Was.AGU2014] J. Wasowski, M. T. Chiaradia, F. Bovenga, R. Nutricato, D. O. Nitti, G. Milillo, "Exploiting COSMO-Skymed Data and Multi-Temporal Interferometry for Early Detection of Landslide Hazard: A Case of Slope Failure and Train Derailment Near Marina Di Andora, Italy". AGU Fall Meeting 2014, Abstract ID:6747, Poster Presentation NH11B-3703, San Francisco, California, USA, 15-19 December 2014.
    The improving temporal and spatial resolutions of new generation space-borne X-Band SAR sensors such as COSMO-SkyMed (CSK) constellation, and therefore their better monitoring capabilities, will guarantee increasing and more efficient use of multi-temporal interferometry (MTI) in landslide investigations. Thanks to their finer spatial resolution with respect to data, X-band InSAR applications are very promising also for monitoring smaller landslides and single engineering structures sited on potentially unstable slopes. This work is focused on the detection of precursory signals of an impending slope failure from MTI time series of ground deformations obtained by exploiting 3 m resolution CSK data. We show the case of retrospectively captured pre-failure strains related to the landslide which occurred on January 2014 close to the town of Marina di Andora. The landslide caused the derailment of a train and the interruption of the railway line connecting north-western Italy to France. A dataset of 56 images acquired in STRIPMAP HIMAGE mode by CSK constellation from October 2008 to May 2014 was processed through SPINUA algorithm to derive the ground surface deformation map and the time series of displacement rates for each coherent radar target. We show that a cluster of moving targets coincides with the structures (buildings and terraces) affected by the 2014 landslide. The analysis of the MTI time series further shows that the targets had been moving since 2009, and thus could have provided a forewarning signal about ongoing slope or engineering structure instability. Although temporal landslide prediction remains difficult even via in situ monitoring, the presented case study indicates that MTI relying on high resolution radars such as CSK can provide very useful information for slope hazard mapping and possibly for early warning. Acknowledgments: DIF provided contribution to data analysis within the framework of CAR-SLIDE project funded by MIUR (PON01_00536).
    DIF provided contribution to data analysis within the framework of CAR-SLIDE project funded by MIUR (PON01_00536).

  • [Was.AGU2014b] J. Wasowski, F. Bovenga, D. O. Nitti, R. Nutricato, M. T. Chiaradia, "High resolution satellite multi-temporal interferometry for landslide and subsidence hazard assessment: An overview". AGU Fall Meeting 2014, Abstract ID:3759, Oral Presentation NH14A-02 (Invited), San Francisco, California, USA, 15-19 December 2014.
    The new and planned satellite missions can not only provide global capacity for research-oriented and practical applications such as mapping, characterizing and monitoring of areas affected by slope and subsidence hazards, but also offer a possibility to push the research frontier and prompt innovative detailed-scale studies on ground movement dynamics and processes. Among a number of emerging space-based remote sensing techniques, synthetic aperture radar (SAR), multi-temporal interferometry (MTI) seems the most promising for important innovation in landslide and subsidence hazards assessment and monitoring. MTI is appealing to those concerned with terrain instability hazards because it can provide very precise information on slow displacements of the ground surface over vast areas with limited vegetation cover. Although MTI techniques are considered to have already reached the operational level, it is apparent that in both research and practice we are at present only beginning to benefit from the high-resolution imagery that is currently acquired by the new generation radar satellites (e.g. COSMO-SkyMed, TerraSAR-X). In this overview we illustrate the great potential of high resolution MTI and explain what this technique can deliver in terms of detection and monitoring of slope and subsidence hazards. This is done by considering different areas characterized by a wide range of geomorphic, climatic and vegetation conditions, and presenting selected case study examples of local to regional scale MTI applications from Europe, China and Haiti. We envision that the current approach to assessment of hazard can be transformed by capitalizing more on the presently underexploited advantage of the MTI technique, i.e. the capability to provide regularly spatially-dense quantitative information for large areas currently unaffected by instabilities, but where the terrain geomorphology and geology may indicate potential for future ground failures.
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  • [Chi.AGU2014] M.T. Chiaradia, K. Tijani, A. Morea, R. Nutricato, L. Guerriero, L. Giannini, L. Nannucci, "Multi-platform Chlorophyll and Sea Surface Temperature data fusion for Potential Fishing Zone detection using MODIS/VIIRS and ancillary data". AGU Fall Meeting 2014, Abstract ID:16210, Poster Presentation OS34B-08, San Francisco, California, USA, 15-19 December 2014.
    Work funded by Apulia Region, in the framework of the project "Sustainable Fishery" (FEP 2007-2013 – Measure 3.1)
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  • [Tij.EGU2014] K. Tijani, A. Morea, M.T. Chiaradia, L. Guerriero, G. Pasquariello, R. Nutricato, "The retrieval of the Potential Fishing Zone (PFZ) information using satellite based chlorophyll and sea surface temperature along the north of Adriatic sea". Abstracts proceedings EGU 2014, Vienna, Austria, 27 April - 02 May 2014. Abstract ID-No: EGU2014-13684. Vol. 16 eISSN: 1607-7962.
    Relevant oceanographic conditions, such as sea surface temperature (SST), chlorophyll concentration (CHL) and oceanic fronts, which strongly influence natural fluctuations of fish stocks, can be observed and measured by remote sensors on satellites and aircraft. The high spatiotemporal frequency of MODIS data (twice per day, 500m resolution) are provided in near-real time to help fishermen save fuel and ship time during their search for fish located along the Adriatic Sea. The purpose of this work is the integration of CHL and SST to generate potential fishing zones (PFZs) using an gradient-based edge detection algorithm [1]. The position of the fronts is detected by a Canny filter [2] were applied to gradient of CHL and SST images; the potential edges were subsequently validated statistically [3] and then were compared in terms of categorized fish catch per unit effort (CPUE, total catch divided by actual fishing hours). The results of this study will be presented and commented.
    Work funded by Apulia Region, in the framework of the project "Sustainable Fishery" (FEP 2007-2013 – Measure 3.1)

  • [Was.EGU2014] J. Wasowski, F. Bovenga, T. Dijkstra, X. Meng, R. Nutricato, and M. T. Chiaradia, " Towards widespread exploitation of high resolution multi-temporal interferometry for monitoring landslide activity: a case-study of Southern Gansu, China". Abstracts proceedings EGU 2014, Vienna, Austria, 27 April - 02 May 2014. Abstract ID-No: EGU2014-14995. Vol. 16 eISSN: 1607-7962.
    Although Multi-Temporal Interferometry (MTI) techniques are considered to have already reached the operational level, it is apparent that, in both research and practice, we are only just beginning to benefit from the high resolution imagery that is currently acquired by the new generation of radar satellites. MTI techniques are not applicable in any environment, but, nonetheless, we foresee a strong possibility that in the future these techniques will see widespread exploitation in support of slope hazard assessments. MTI applications will become increasingly important in cases where little or no conventional monitoring is feasible (e.g. remote locations and limited funds). The tremendous potential of MTI is illustrated using selected examples of applications ranging from local to catchment scales. A particular focus is on the use of MTI for the investigation of slope instability in the remote high mountain region of Zhouqu, Southern Gansu, known to be affected by large magnitude (M7-8) earthquakes and catastrophic mass movements. The MTI processing of high resolution (3 m) COSMO/SkyMed (CSK) satellite images produced spatially dense information (more than 1000 radar targets/km2) on ground surface displacements. A substantial portion of the radar targets showed significant displacements (from few to over 100 mm/yr), denoting widespread slope instability. In particular, the MTI results provided valuable information on the activity of some very large, apparently slow moving landslides that represent a persistent hazard to the local population and infrastructure, particularly as these landslides are known to undergo periods of increased activity resulting in river damming and disastrous flooding. Given the general lack of field monitoring data on slope instability in Southern Gansu, the MTI-derived displacements offer a unique form of remote displacement monitoring that provides valuable information to experts tasked with formulating strategies for hazard management in these difficult terrains. Furthermore, this study shows that high resolution CSK imagery results in high radar target density, so that MTI can also assist with site specific scale assessments of slope deformation hazards.
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Other poster/slideshow presentations

  • [Nit.NEREUS2014] D. O. Nitti, "Monitoring of Transport Infrastructures by Using Synthetic Aperture Radar Satellites". NEREUS International Conference "Space4You - Space, a driver for Competitiveness and Growth", Bari,27-28 February 2014. http://www.nereus-regions.eu/sites/all/events/BARI/PPT/NEREUS_Space4You_Nitti_27Feb2014.v3.pdf
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Peer-Reviewed Journal Articles

  • [Bov.IJRS2013] F. Bovenga, D. O. Nitti, G. Fornaro, F. Radicioni, A. Stoppini, R. Brigante, "Using C/X-band SAR interferometry and GNSS measurements for the Assisi landslide analysis". International Journal of Remote Sensing, vol. 34(11), pp. 4083-4104, 2013. DOI:10.1080/01431161.2013.772310. ISSN 0143-1161 (Print), 1366-5901 (Online). Scopus: 2-s2.0-84874595989. IF: 1.14 (Year: 2012 - Source: ResearchGate - http://is.gd/ZyQELr)
    This work presents an analysis of the applicability of synthetic aperture radar (SAR) interferometry to landslide monitoring. This analysis was carried out by using differ- ent interferometric approaches, different spaceborne SAR data (both in the and in the X-band), and in situ global navigation satellite system (GNSS) measurements. In particular, we investigated both the reliability of displacement monitoring and the issues of the cross-comparison and validation of the interferometric synthetic aperture radar (InSAR) results. The work was focused on the slow-moving landslide that affects a relevant part of the urban area of the historical town of Assisi (Italy). A ENVISAT advanced synthetic aperture radar (ENVISAT ASAR) dataset acquired between 2003 and 2010 was processed by using two different interferometric techniques, to allow cross-comparison of the obtained displacement maps. Good corre- spondence between the results was found, and a deeper analysis of the movement field was possible. Results were further compared to a set of GNSS measurements with a 7 year overlap with SAR data. A comparison was made for each GNSS marker with the surrounding SAR scatterers, trying to take into account local topological effects, when possible. Further, the high-resolution X-band acquired on both ascending and descending tracks by the COSMO-SkyMed (CSK) constellation was processed. The resultant dis- placement fields show good agreement with and GNSS measurements and sensible increase in the density of measurements.
    ENVISAT and COSMO-SkyMed data were provided, respectively, by ESA and ASI in the framework of the MORFEO project (ASI contract no. I/045/07/0). We thank the Provveditorato alle Opere Pubbliche per la Toscana e l’Umbria for funding the GNSS monitoring activity on the Assisi landslide.

  • [Nit.EUJRS2013] D. O. Nitti, F. Bovenga, R. Nutricato, F. Intini, M. T. Chiaradia, “On the use of COSMO/SkyMed data and Weather Models for interferometric DEM generation”. European Journal of Remote Sensing, vol. 46, pp.250-271, 2013. DOI: 10.5721/EuJRS20134614. ISSN: 2279-7254. WOS:000318651700014. Scopus: 2-s2.0-84875201169. IF: 0.33 (Year: 2012 - Source: ResearchGate - http://is.gd/a1YHlW)
    This work experiments the potentialities of COSMO/SkyMed (CSK) data in providing interferometric Digital Elevation Model (DEM). We processed a stack of CSK data for measuring with meter accuracy the ground elevation on the available coherent targets, and used these values to check the accuracy of DEMs derived from 5 tandem-like CSK pairs. In order to suppress the atmospheric signal we experimented a classical spatial filtering of the differential phase as well as the use of numerical weather prediction (NWP) model RAMS. Tandem-like pairs with normal baselines higher than 300 m allows to derive DEMs fulfilling the HRTI Level 3 specifications on the relative vertical accuracy, while the use of NWP models still seems unfeasible especially for X-band.
    Work supported by ASI (Agenzia Spaziale Italiana) in the framework of the project “AO-COSMO Project ID-1462 - Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation - ASI Contract I/063/09/0”.

  • [Ref.EUJRS2013] A. Refice, A. Belmonte, F. Bovenga, G. Pasquariello, R. Nutricato, “On the interpolation of sparse-grid InSAR data without need of phase unwrapping". European Journal of Remote Sensing, vol. 46, pp.807-821, 2013. DOI: 10.5721/EuJRS20134648. Scopus: 2-s2.0-84890397441. WOS:000328277100010. Online ISSN: 2279-7254. IF: 1.31 (Year: 2013 - Source: https://goo.gl/x5icVo)
    Sparse phase measurements often need to be interpolated on regular grids, to extend the information to unsampled locations. Typical cases involve the removal of atmospheric phase screen information from Interferometric Synthetic Aperture Radar (InSAR) stacks, or the retrieval of displacement information over extended areas in Persistent Scatterers Interferometry (PSI) applications, when sufficient point densities are available. This operation is usually done after a phase unwrapping (PU) of the sparse measurements to remove the sharp phase discontinuities due to the wrap operation. PU is a difficult and error-prone operation, especially for sparse data. In this work, we investigate from the empirical point of view an alternative procedure, which involves an interpolation of the complex field derived from the sparse phase measurements. Unlike traditional approaches, our method allows to bypass the PU step and obtain a regular-grid complex field from which a wrapped phase field can be extracted. Under general conditions, this can be shown to be a good approximation of the original phase without noise. Moreover, the interpolated, wrapped phase field can be fed to state-of-the-art, regular-grid PU algorithms, to obtain an improved absolute phase field, compared to the canonical method consisting of first unwrapping the sparse-grid data. We evaluate the performance of the method in simulation, comparing it to the classical methodology described above, as well as to an alternative procedure, recently proposed, to reduce a sparse PU problem to a regular-grid one, through a nearest-neighbor interpolation step. Results confirm the increased robustness of the proposed method with respect to the effects of noise and undersampling.
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International Conference Proceedings

  • [Nut.WLF2book2013] R. Nutricato, J. Wasowski, F. Bovenga, A. Refice, G. Pasquariello, D. O. Nitti, M. T. Chiaradia, "C/X-band SAR interferometry used to monitor slope instability in Daunia, Italy". Proceeding of the the Second World Landslide Forum, published in Volume 2 "Early warning, instrumentation and monitoring" of the Springer Book Series for WLF2 "Landslide science and practice", pp. 423-430, Springer-Verlag Berlin Heidelberg 2013. ISBN 978-3-642-31444-5. DOI: 10.1007/978-3-642-31445-2_55. Scopus: 2-s2.0-84898064174.
    We apply multi-temporal Persistent Scatterer Interferometry (PSI) analysis to investigate slope instability in the Daunia region in the Southern Apennine Mountains. Daunia includes many small hill-top towns affected by landslides and is of particular interest for the Civil Protection – Regione Puglia Authority, one of the end users of the PSI deformation maps. The SPINUA algorithm is used to perform interferometric analysis and detect, with mm precision, the presence of ground surface movements. Consistent results on very slow displacements are obtained using the radar imagery acquired between 2002 and 2010 by the ENVISAT ESA satellite (, medium spatial resolution sensor) and the images acquired between 2010-2011 by the X-band high resolution sensor onboard the TerraSAR-X satellite. Thanks to the finer spatial resolution the X-band PSI applications are very promising for monitoring single man-made structures and slope/ground instability in areas where PS density is low.
    Work supported by Puglia Region in the framework of the project “FRANE PUGLIA - Rilevamento di deformazioni al suolo con tecniche satellitari avanzate”. ENVISAT data are provided by ESA under CAT-1 project ID 2653. TerraSAR-X data are provided by DLR under TerraSAR-X General AO Project ID MTH0432.

  • [For.WLF2book2013] G. Fornaro, D. O. Nitti, R. Nutricato, F. Bovenga, D. Peduto, L. Cascini, "Methodological and Technological Advances in the Application of Spaceborne DInSAR for Landslide Monitoring". Proceeding of the the Second World Landslide Forum, published in Volume 2 "Early warning, instrumentation and monitoring" of the Springer Book Series for WLF2 "Landslide science and practice", pp. 379-384, Springer-Verlag Berlin Heidelberg 2013. ISBN 978-3-642-31444-5. DOI: 10.1007/978-3-642-31445-2_49. Scopus: 2-s2.0-84898059923.
    Differential Interferometry Synthetic Aperture Radar is a mature remote sensing technique broadly used for the measurement of slow deformations with major application in several fields. In the last years, the application to slow moving landslides has grown quickly and several examples of the monitoring capability can be found in the literature. Main goal of this work is the description of the advances in terms of products that can be achieved from both an innovative methodological approach to DInSAR data analysis and the technological improvements related to the last generation of sensors.
    ENVISAT and COSMO-SkyMED images on Ivancich test case were provided respectively by ESA and ASI in the framework of the MORFEO project (ASI Contract n. I/045/07/0).

  • [Was.EUROCK2013] J. Wasowski, F. Bovenga, D. Nitti, R. Nutricato, "Monitoring unstable slopes using Persistent Scatterers Interferometry: opportunities and challenges". Proceedings of Eurock 2013 ISRM International Symposium, Wroclaw, Poland, September 21-26, 2013. In book: Rock Mechanics for Resources, Energy and Environment - Kwasniewski and Lydzba (eds), pp. 713-717, (c) 2013 Taylor and Francis Group, London, ISBN 978-1-138-00080-3.
    Advanced space-borne Persistent Scatterers Interferometry (PSI) can provide wide-area coverage (thousands km2) and precise (mm-cm resolution), spatially dense information (from hundreds to over thousand measurement points/km2) on ground surface deformations. Furthermore, new application opportunities are emerging thanks to i) the greater data availability offered by recent launches of radar satellites, ii) the improved capabilities of the new space radar sensors (Cosmo-SkyMed, TerraSAR-X) in terms of resolution (from 3 to 1 m) and revisit time (from 11 to 4 days). Although, the applicability of radar interferometry to regional and local-scale investigations of slope instability have been demonstrated in several studies, more progress is needed in the integration of PSI results with ground data and in their validation in order to foster a more profitable use of this technique. It is also expected that numerical modeling slope deformations detected by radar satellites should help to constrain the data interpretation.
    Work supported in part by the Italian Space Agency (ASI) - COSMO-SkyMed AO Project ID 1820. ENVISAT and COSMO-SkyMed data were provided, respectively, by the European Space Agency (ESA) under CAT-1 project ID 2653 and by ASI.

  • [Bov.IGARSS2013] F. Bovenga, F. Rana A. Refice, D.O. Nitti, N. Veneziani, "Frequency coherent vs. temporally coherent targets". IEEE International Geoscience and Remote Sensing Symposium, July 21-26, 2013, Melbourne (Australia). ISSN 2153-6996. Print ISBN: 978-1-4799-1114-1. DOI: 10.1109/IGARSS.2013.6721103. SCOPUS: 2-s2.0-84894235469
    The Multi-Chromatic Analysis (MCA) uses interferometric pairs of SAR images processed at range sub-bands and explores the phase trend of each pixel as a function of the different central carrier frequencies. The MCA technique introduces the concept of targets exhibiting stable radar returns across the frequency domain (PSfd). In this work we compare this stability along frequencies with the temporal stability which is at the base of persistent scatterers interferometry (PSI) techniques. Different populations of PSfd and “temporal” PS were derived by using COSMOSkyMed SAR data. An ad hoc processing scheme was developed to derive PSI products by processing the same range sub-bandwidth used by the MCA in order to guarantee the same scattering conditions. The populations of PSfd and “temporal” PS were compared and preliminary considerations provided concerning the scattering properties of the targets selected by the two criteria.
    Work supported by both ASI Contr. N I/047/09/0, and ESA ESTEC Contr. N. 21319/07/NL/HE. COSMO/SkyMed data provided by ASI under the AO-COSMO Project ID-1820.

  • [Nut.SPIE2013] R. Nutricato, D. O. Nitti, F. Bovenga, A. Refice, J. Wasowski, M. T. Chiaradia, "C/X-band SAR interferometry applied to ground monitoring: examples and new potentials". Proc. SPIE 8891, SAR Image Analysis, Modeling, and Techniques XIII, 88910C (October 17, 2013); doi:10.1117/12.2029096. ISSN: 0277-786X. ISBN: 9780819497604. Scopus: 2-s2.0-84889063441. WOS:000327079900009
    Classical applications of the MTInSAR techniques have been carried out in the past on medium resolution data acquired by the ERS, Envisat (ENV) and Radarsat sensors. The new generation of high-resolution X-Band SAR sensors, such as TerraSAR-X (TSX) and the COSMO-SkyMed (CSK) constellation allows acquiring data with spatial resolution reaching metric/submetric values. Thanks to the finer spatial resolution with respect to data, X-band InSAR applications result very promising for monitoring single man-made structures (buildings, bridges, railways and highways), as well as landslides. This is particularly relevant where data show low density of coherent scatterers. Moreover, thanks again to the higher resolution, it is possible to infer reliable estimates of the displacement rates with a number of SAR scenes significantly lower than in within the same time span or by using more images acquired in a narrower time span. We present examples of the application of a Persistent Scatterers Interferometry technique, namely the SPINUA algorithm, to data acquired by ENV, TSX and CSK on selected number of sites. Different cases are considered concerning monitoring of both instable slopes and infrastructure. Results are compared and commented with particular attention paid to the advantages provided by the new generation of X-band high resolution space-borne SAR sensors.
    Work supported by the project “Landslide Monitoring and Mapping System - CAR-SLIDE” (PON 01 00536). TerraSAR-X data are provided by DLR in the frame of the TerraSAR-X General AO Projects MTH0432. CSK data are provided by ASI (Agenzia Spaziale Italiana) in the framework of the CAR-SLIDE (PON 01 00536) project. ENVISAT data are provided by ESA under CAT-1 project ID 2653.

  • [Nit.SPIE2013] D. O. Nitti, F. Bovenga, R. Nutricato, F. Intini, M. T. Chiaradia, "DEM generation by using COSMO-SkyMed tandem pairs and Weather Models". Proc. SPIE 8891, SAR Image Analysis, Modeling, and Techniques XIII, 88910E (October 17, 2013); doi:10.1117/12.2048902. ISSN: 0277-786X. ISBN: 9780819497604. Scopus: 2-s2.0-84889031791. WOS:000327079900011
    The paper investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement through conventional and multi-temporal SAR Interferometry (InSAR), with particular attention devoted to the impact of the improved spatial resolution with respect to the previous SAR sensors. The Atmospheric Phase Screen (APS) is wellknown to be the main source of errors for accurate topographic mapping through SAR interferometry, in case of monostatic sensors. Different strategies can be adopted to filter out this signal, ranging from the exploitation of the wellknown spatial and temporal statistics of the APS to the estimation of independent APS measurements through Numerical Weather Prediction (NWP) models. Their feasibility and the achievable accuracies are discussed here.
    Work supported by ASI (Agenzia Spaziale Italiana) in the framework of the project “AO- COSMO Project ID-1462 - Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation - ASI Contract I/063/09/0”. Authors would like to thank Rosa Pacione (eGEOS/ASI-CGS) and Francesco Vespe (ASI/CGS) for the fruitful collaboration and GPS Zenith Total Delay (ZTD) data provided.

  • [Bar.EWRA2013] E. Barca, G. Passarella, M. Vurro, A. Morea, "Optimal redesign of groundwater monitoring networks: a data-driven, multi-approach software". Proceedings of 8th International Conference of EWRA "Water Resources Management in an Interdisciplinary and Changing Context", Porto, Portugal, 26th-29th June 2013. ISBN: 978-989-95557-8-5
    Within recent WFD and the modification introduced into national water related legislation, monitoring assumes great importance in the frame of territorial managerial activities. Recently, a number of public environmental agencies invested resources in planning improvements on existing monitoring networks. A lot of reasons justify the optimal redesign of a monitoring network. In fact, a modest or sparse coverage of the monitored area or redundancies and clustering of monitoring locations often make impossible to provide the manager with a sufficient knowledge for decision-making processes. These are typical cases requiring an optimal redesign of the whole network; particular emphasis shall be devoted to quality groundwater monitoring network. Using reliable stochastic or deterministic methods, it is possible to rearrange the existing network by eliminating, adding or moving monitoring locations producing the most uniform arrangement among any possible. In this paper, some spatial optimization methods have been selected as more effective among those reported in literature and implemented in a software able to carry out a complete redesign of an existing monitoring network. Both stochastic and deterministic methods have been embedded in the software with the option of choosing, case by case, the most suitable with regard to the available information. Finally, an application to the existing regional groundwater level monitoring network of the aquifer of Tavoliere located in Apulia (South Italy) is presented.
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  • [Ref.Earsel2013] A. Refice, G. Pasquariello, A. D’Addabbo, F. Bovenga, R. Nutricato, D. Capolongo, A. Lepera, L. Pietranera, S. Manfreda, A. Cantisani, A. Sole, "Inundation monitoring through high-resolution SAR/InSAR data and 2D hydraulic simulations". Proceedings of 33th EARSeL Symposium, Towards Horizon 2020: Earth Observation and Social Perspectives, Matera (Italy), 3 - 6 June 2013, pp. 15-22. Editors: R. Lasaponara, N. Masini, M. Biscione, CNR, Italy. ISBN: 978-88-89693-34-6.
    In the present paper, COSMO-SkyMed high-resolution data acquired on the southern Basilicata region (Italy) are used for flood hazard monitoring. We concentrate on the flood event of Nov. 2-4, 2010, for which multi-temporal SAR data were available over the Bradano River downstream area in the same acquisition geometry, which allows interferometric processing. SAR intensity data analysis of two acquisitions dated 3 and 4 Nov., performed through optimized thresholding algorithms, shows good results, highlighting the temporal evolution of the flood throughout the two days, as also confirmed by a comparison with the results of a 2D hydraulic simulation of the same event. Additional use of the one-day co-event coherence channel, and then of more intensity and coherence data layers in the multi-temporal dataset, through automated clustering procedures, helps discriminating in more detail some uncertain cases regarding inundated fields, and suggest procedures to shed light on the spatio-temporal backscattering patterns of flood-prone areas.
    COSMO-SkyMed data were courtesy of e-Geos s.p.a. The authors thank Dr. Ing. D. O. Nitti, of Geophysical Application Processing s.r.l., for the InSAR data processing.

Conference Abstracts

  • [Nit.AGU2013] D. O. Nitti, M. T. Chiaradia, R. Nutricato, F. Bovenga, A. Refice, M. F. Bruno, E. Ciracì, A. F. Petrillo, L. Guerriero, "On the use of Numerical Weather Models for improving SAR geolocation accuracy (ID: 1795652)". AGU Fall Meeting 2013 Abstract, G31A-0935, San Francisco, California, USA, 9-13 Dec. 2013. http://abstractsearch.agu.org/meetings/2013/FM/sections/G/sessions/G31A/abstracts/G31A-0935
    Precise estimation and correction of the Atmospheric Path Delay (APD) is needed to ensure sub-pixel accuracy of geocoded Synthetic Aperture Radar (SAR) products, in particular for the new generation of high resolution side-looking SAR satellite sensors (TerraSAR-X, COSMO/SkyMED). The present work aims to assess the performances of operational Numerical Weather Prediction (NWP) Models as tools to routinely estimate the APD contribution, according to the specific acquisition beam of the SAR sensor for the selected scene on ground. The Regional Atmospheric Modeling System (RAMS) has been selected for this purpose. It is a finite-difference, primitive equation, three-dimensional non-hydrostatic mesoscale model, originally developed at Colorado State University [1]. In order to appreciate the improvement in target geolocation when accounting for APD, we need to rely on the SAR sensor orbital information. In particular, TerraSAR-X data are well-suited for this experiment, since recent studies have confirmed the few centimeter accuracy of their annotated orbital records (Science level data) [2]. A consistent dataset of TerraSAR-X stripmap images (Pol.:VV; Look side: Right; Pass Direction: Ascending; Incidence Angle: 34.0÷36.6 deg) acquired in Daunia in Southern Italy has been hence selected for this study, thanks also to the availability of six trihedral corner reflectors (CR) recently installed in the area covered by the imaged scenes and properly directed towards the TerraSAR-X satellite platform. The geolocation of CR phase centers is surveyed with cm-level accuracy using differential GPS (DGPS). The results of the analysis are shown and discussed. Moreover, the quality of the APD values estimated through NWP models will be further compared to those annotated in the geolocation grid (GEOREF.xml), in order to evaluate whether annotated corrections are sufficient for sub-pixel geolocation quality or not. Finally, the analysis will be extended to a limited number of COSMO/SkyMED data available over the area of interest in order to achieve preliminary indications on the quality of orbital records for the latter X-band constellation.
    TSX data provided by DLR under the TerraSAR-X General AO Project MTH0432. CSK data provided by ASI under the AO-COSMO Project ID-1462. This work has been partially funded by MIUR in the framework of the project CAR-SLIDE (PON01_00536).

  • [Nut.AGU2013] R. Nutricato, J. Wasowski, M.T. Chiaradia, B. E. Piard, P. Mondesir, "Multi-temporal interferometric monitoring of ground deformations in Haiti with COSMO/SkyMed HIMAGE data (ID: 1808199)". AGU Fall Meeting 2013 Abstract, NH13A-1589, San Francisco, California, USA, 9-13 Dec. 2013.
    The catastrophic Mw=7.0 shallow earthquake of 12 January 2010 that struck Haiti have led to numerous studies focused on the geodynamics of the region. In particular, the co-seismic fault mechanism of the 2010 Haiti earthquake as well as post-seismic deformations have been investigated through SAR interferometry (InSAR) techniques, thanks to the availability of satellite SAR sensors operating in different radar bands (ENVISAT ASAR, ALOS PALSAR, TerraSAR-X, COSMO/SkyMed). Moreover, advanced multitemporal SAR interferometry (MTI) based on COSMO/SkyMED (CSK) data is well suited for the detection and monitoring of post-seismic ground or structural instabilities. Indeed, with its short revisit time (up to 4 days) CSK allows building interferometric stacks much faster than previous satellite missions, like ERS/ENVISAT. Here we report the first outcomes of the MTI investigation based on high resolution (3 m) CSK data, conducted in the framework of a scientific collaboration between the Centre National de l'Information Géo-Spatiale (CNIGS) of Haiti and the Department of Physics (DIF) of the University of Bari, Italy. We rely on a stack of 89 CSK data (image mode: HIMAGE; polarization: HH; look side: right; pass direction: ascending; beam: H4-0A) acquired by the Italian Space Agency (ASI) over the Port-au-Prince (PaP) metropolitan and surrounding areas that were severely hit by the 2010 earthquake. CSK acquisitions span the period June 2011 ÷ February 2013, which is sufficient for detecting and monitoring significant ground instabilities. The MTI results were obtained through the application of the SPINUA processing chain, a Persistent Scatterers Interferometry (PSI)-like technique. In particular, we detected significant subsidence phenomena affecting river deltas and coastal areas of the PaP and Carrefour region. The maximum rate of subsidence movements exceed few cm/yr and this implies increasing flooding (or tsunami) hazard. Furthermore, maximum subsidence rates were encountered in areas with high population density and this translates into high potential risk. The MTI results also revealed the presence of very slow slope movements and local ground / structure instabilities. Some of these may have been initially triggered by the 2010 event. Elsewhere the MTI-detected displacements can be related to the presence of poorly constructed buildings. This case study demonstrates that MTI represents a very good option for the assessments of ground / structure instability in regions that lack in situ monitoring data. In view of this the results of this study will be transferred to the Civil Protection of Haiti.
    CSK images provided by ASI (Agenzia Spaziale Italiana) in the framework of a scientific collaboration between the Centre National de l'Information Géo-Spatiale (CNIGS) of Haiti and the Department of Physics (DIF) of the University of Bari, Italy. The authors would like to thank Aldo Giovacchini (Consorzio ITA), Fabio Bovenga (CNR-ISSIA), D.O. Nitti (GAP Srl) and E. Ciracì (UCI) for helpful contributions to the achieved results.

Peer-Reviewed Journal Articles

  • [Bov.RSE2012] F. Bovenga, J. Wasowski, D. O. Nitti, R. Nutricato, M. T. Chiaradia, "Using Cosmo/SkyMed X-band and ENVISAT SAR Interferometry for landslide analysis". Remote Sensing of Environment - 2012, 119: 272-285. DOI: 10.1016/j.rse.2011.12.013. ISSN: 0034-4257. WOS:000301892200025. Scopus: 2-s2.0-84856086628. IF: 5.103 (Year: 2012 - Source: ResearchGate - http://is.gd/L3bzT5)
    We explore new possibilities offered by the recently available X-band satellite radar sensors for landslide hazard assessments on a detailed scale, with particular reference to the exploitation of Persistent Scatterers Interferometry (PSI) techniques. Special attention is paid to the impact of the improved resolution of new Xband radar imagery on the PSI results, in terms of quality and quantity of useful information. This evaluatiois supported by theoretical modelling as well as by the comparison of results from X-band (CSK) and C-ban(ENVISAT) PSI for two areas of interest: one in Italy and the other in Switzerland. It is demonstrated that with respect to medium resolution ENVISAT PS processing, fewer CSK high resolution images are sufficient to achieve comparable precision of the mean displacement velocity estimates. This, together with the shorter revisit times provided by the CSK constellation, can be very important when dealing with emergency situations. Furthermore, it is quantified that from about 3 to 11 times greater PS densities are obtained with the higher resolution X-band data. This implies more information about ground surface displacements as well as improved landslide monitoring and slope instability investigation capabilities. Furthermore, ground displacement measurements can be interpreted without local knowledge of the focus area or in situ controls, and, nonetheless, guide single hillslope instability assessments with support of Google Earth and its high resolution optical imagery. This “blind” approach will allow one to monitor remote and poorly known regions at high risk of potentially disastrous slope failures.
    The work has been in part supported by the MORFEO project funded by the Italian Spatial Agency (ASI) (ASI Contract n. I/045/07/0). ENVISAT and COSMO-SkyMED data were provided respectively by ESA and ASI in the framework of the MORFEO project. We thank three anonymous reviewers for their very helpful comments.

  • [Cza.PGR2012] M. Czarnogórska, M. Graniczny, S. Uoecinowicz, R. Nutricato, S. Triggiani, D. O. Nitti, F. Bovenga, J. Wasowski, “Ground deformations along SW coast of the Gulf of Gdañsk analysed using satellite radar interferometry”. Przeglad Geologiczny (Polish Geological Review), vol. 60, nr 3, 2012. ISSN-0033-2151. Scopus: 2-s2.0-84862733602. IF: 0.186 [2-years Cites per Doc] (Year: 2012 - Source: SJR - http://is.gd/BXi24r)
    The paper presents results of SPINUA (Stable Point Interferometry over Unurbanised Areas) Persistent Scatterers Interferometry (PSI) processing chain to study Earth surface deformations along the SW coast of the Gulf of Gdañsk, along the SE part of the Baltic Sea. As the input for SPINUA techniques 40 descending ERS-1/2 SLC (Frame = 251, Track = 36) images from the period 1995–2001 has been used. The area of interest (AOI) includes few cities and several towns, villages and harbors. The low lying coastal areas of the SW part of the Gulf of Gdañsk are at risk of floods and marine erosion. The PSI results, however, did not reveal the presence of a regional scale, spatially consistent pattern of displacements. It is likely that any crustal deformations in the AOI simply do not exceed ±2 mm/year, which is the velocity threshold we assumed to distinguish between moving and non-moving persistent scatterers (PS). Importantly, for the most part the urban areas of the main cities (Gdañsk, Gdynia and Sopot) results show ground stability. Nevertheless, significant downward movements up to several mm/year, are locally noticed in the Vistula river delta – alluvial plain system located in the coastal zone east of Gdañsk as well as in the inland area west of the Gdañsk city. Indeed, the highest subsidence rates (–12 mm/year) was observed in the Gdañsk petroleum refinery constructed on alluvial sediments. Thus the anthropogenic loading and consolidation of the recent deposits can locally be an important factor causing ground subsidence.
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Book Chapters

  • [Ber.HARTES2012] K. Bertels, A. Lattanzi, E. Ciavattini, F. Bettarelli, M. T. Chiaradia, R. Nutricato, A. Morea et al., "The hArtes Tool Chain". In book: “Hardware/Software Co-design for Heterogeneous Multi-core Platforms”, edited by K. Bertels, published 2012 by Springer, pp. 9-109. ISBN 978-94-007-1405-2. e-ISBN 978-94-007-1406-9. DOI 10.1007/978-94-007-1406-9.
    The hArtes project1 was started as an innovative European project (funded by European Union) aiming at laying the foundations of a new holistic approach for the design of complex and heterogeneous embedded solutions (hardware and software), from the concept to the silicon (or B2B, from the brain to bits). The hArtes stands for “holistic Approach to reconfigurable real time embedded systems”. As defined in the Embedded Systems Chapter of the IST 2005-06 Work Programme the objective of the hArtes project is to “develop the next generation of technologies, methods and tools for modeling, design, implementation and operation of hardware/software systems embedded in intelligent devices. An end-to-end systems (holistic) vision should allow building cost-efficient ambient intelligence systems with optimal performance, high confidence, reduced time to market and faster deployment”. The hArtes project aims to lay the foundation for a new holistic (end-to-end) approach for complex real-time embedded system design, with the latest algorithm exploration tools and reconfigurable hardware technologies. The proposed approach will address, for the first time, optimal and rapid design of embedded systems from high-level descriptions, targeting a combination of embedded processors, digital signal processing and reconfigurable hardware. The project ended with an important scientific and technical contribution that resulted in more than 150 international publications as well as a spin-off company, BlueBee.2 From the application point of view, the complexity of future multimedia devices is becoming too big to design monolithic processing platforms. This is where the hArtes approach with reconfigurable heterogeneous systems becomes vital. As a part of the project, a modular and scalable hardware platforms will be developed that can be reused and re-targeted by the tool chain to produce optimized real-time embedded products. The results obtained will be evaluated using advanced audio and video systems that support next-generation communication and entertainment facilities, such as immersive audio and mobile video processing. Innovations of the hArtes approach include: (a) support for both diagrammatic and textual formats in algorithm description and exploration, (b) a framework that allows novel algorithms for design space exploration, which aims to automate design partitioning, task transformation, choice of data representation, and metric evaluation for both hardware and software components, (c) a system synthesis tool producing near optimal implementations that best exploits the capability of each type of processing element; for instance, dynamic reconfigurability of hardware can be exploited to support function upgrade or adaptation to operating conditions.
    This book describes the outcome of the hArtes project (IST-035143) supported by the Sixth Framework Programme of the European Community under the thematic area Embedded Systems.

International Conference Proceedings

  • [Was.ISL2012] J. Wasowski, F. Bovenga, Nitti D, R. Nutricato (2012). Investigating landslides with Persistent Scatterers Interferometry (PSI): current issues and challenges. In: (a cura di): Erik Eberhardt, Corey Froese, Keith Turner, S. Leroueil, Landslides and Engineered Slopes: Protecting Society through Improved Understanding. VOLUME 2: Simulating and managing rock fall. Proceedings of the 11th International and 2nd North American Symposium on Landslides and Engineered Slopes. vol. 2, p. 1295-1301, CRC press, Taylor and Francis Group., ISBN: 978-0415621236.
    Examples of slope and associated infrastructure instability assessments by PSI are presented to highlight current application opportunities related to i) the greater data availability offered by recent launches of radar satellites and ii) the improved capabilities of the new space-borne radar sensors (e.g. Cosmo-SkyMed, TerraSAR-X) in terms of resolution (from 3 to 1 m) and revisit time (from 11 to 4 days). Attention is drawn to the main factors that limit the general applicability of PSI in landslide investigations, to the difficulties in inferring the exact cause(s) of very slow displacements (mm-cm/ year) commonly registered on radar targets and to the risks of misinterpretation. Specific recommendations and guidelines are offered on how to mitigate PSI limitations and avoid erroneous interpretations. The utility of Google EarthTM tools for 3D visualization and preliminary reconnaissance analysis of PSI results is also emphasized.
    Our efforts were in part supported by the Italian Space Agency (ASI) - Contract I/045/07/0. ENVI-SAT and TerraSAR-X data were provided, respec-tively, by the European Space Agency (ESA) under CAT-1 project ID 2653 and by the German Space Agency (DLR) under TerraSAR-X General AO Pro-ject ID MTH0432.

  • [Rad.FIG2012] F. Radicioni, A. Stoppini, G. Fornaro, F. Bovenga, D. O. Nitti, "Long-Term GNSS and SAR Data Comparison for the Deformation Monitoring of the Assisi Landslide". Proceedings of the FIG Working Week 2012 - Knowing to manage the territory, protect the environment, evaluate the cultural heritage. Rome, Italy, 6-10 May 2012. ISBN 97887-90907-98-3.
    A relevant part of the Assisi urban area (central Italy), built up after 1950 and located outside of the ancient town center, is interested by a landslide characterized by a slow rate of movement, which has caused important damages to buildings for an accumulation effect in time. The movements of the soil surface have both a horizontal and a vertical component. A GNSS network for deformation monitoring purposes has been established over the area since 1995, connecting by means of a baseline network the moving region with stable geologic formations located well outside of the landslide body. Further (1999), a leveling network has been added to improve the definition of the vertical component of the motion field. Surveys of both GNSS and leveling networks have been carried out in time, with an approximately annual cadence, until the actuality. Time series of coordinates and heights spanning along the observation period (1995-2010) are hence available for the network points. The Assisi landslide area has also been investigated by means of satellite SAR interferometry InSAR: the data here presented derive from the analysis of ENVISAT ASAR data spanning in time from 2003 to 2010, thus with a 7-years overlapping with the GNSS and leveling surveys, which make possible a comparison. The comparison has been made for each GNSS marker with the surrounding InSAR scatters, trying to take into account local topological effects when possible. A good agreement between the results of the different techniques has been found in most cases, and a deeper analysis of the movement field and the landslide edge is derived from the complete set of data.
    We thank the Provveditorato alle Opere Pubbliche per la Toscana e l’Umbria for funding the monitoring activity on the Assisi landslide.

  • [Nit.IGARSS2012] D. O. Nitti, F. Bovenga, R. Nutricato, F. Intini, M. T. Chiaradia, R. Pacione, F. Vespe, "On the use of COSMO-SkyMed SAR data and Numerical Weather Models for interferometric DEM generation". Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 22-27, 2012. Munich, Germany. DOI: 10.1109/IGARSS.2012.6350551. ISSN: 2153-6996. eISSN: 2153-7003. E-ISBN : 978-1-4673-1158-8. Print ISBN: 978-1-4673-1160-1. Scopus: 2-s2.0-84873191384. WOS:000313189404012
    The present study is aimed at investigating the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. Assuming no movement and successful orbital error removal, the main problem in height computation through InSAR techniques derives from the interferometric phase artifacts related to the interaction between microwave and the lower layers of the atmosphere (APS, Atmospheric Phase Screen). Different strategies can be adopted to filter out this signal, ranging from the exploitation of the well-known spatial and temporal statistics of the APS to the estimation of independent APSmeasurements through Numerical Weather Prediction (NWP) models. Their feasibility and the achievable accuracies are discussed here.
    Work supported by ASI in the framework of the AO Projects ID-1462 “Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation” (Contract n. I/063/09/0) and ID-2103 “Advanced 2D and 3D focusing of COSMO/SkyMed SAR data” (Contract n. I/059/09/0). GPS data analyzed by e-GEOS under ASI contract I-014-10-0.

  • [Chi.IGARSS2012] M. T. Chiaradia, G. Fornaro, A. Freni, G. Franceschetti, P. Imperatore, F. Intini, A. Iodice, A. Mori, D. O. Nitti, R. Nutricato, D. Reale, D. Riccio, P. Trivero. "COSMO/SkyMed AO Projects – Advanced 2D and 3D focusing of COSMO/SkyMed SAR data". Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 22-27, 2012. Munich, Germany. DOI: 10.1109/IGARSS.2012.6352603. ISSN : 2153-6996. eISSN: 2153-7003. E-ISBN : 978-1-4673-1158-8. Print ISBN: 978-1-4673-1160-1. Scopus: 2-s2.0-84873160925. WOS:000313189406192
    We present a research project, funded by the Italian Space Agency (ASI), aimed at performing 2D and 3D Focusing of COSMO/SkyMed (CSK) SAR Data. We describe the main objectives of the project, briefly illustrate employed techniques, and finally present the obtained results. The latter show that sub-meter resolution can be achieved in the enhanced spotlight CSK acquisition mode, and that by using 3D focusing it is possible to resolve scatterers at different slant heights within the same range-azimuth resolution cell, even in areas characterized by severe height discontinuities and large thermal dilations effects.
    Work funded by ASI within the COSMO/SkyMed Announcement of Opportunity ("Advanced Focusing of COSMO/SkyMed Data", ID 2103).

  • [Bov.IGARSS2012] F. Bovenga, F. Rana, A. Refice, D. O. Nitti, N. Veneziani. "Interferometric multi-chromatic analysis of COSMO-SkyMed data for height retrieval". Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 22-27, 2012. Munich, Germany. DOI: 10.1109/IGARSS.2012.6350579. ISSN: 2153-6996. eISSN: 2153-7003. E-ISBN: 978-1-4673-1158-8. Print ISBN: 978-1-4673-1160-1. Scopus: 2-s2.0-84873184555. WOS:000313189403240.
    The Multi-Chromatic Analysis can be applied to interferometric pairs of SAR images processed at range subbands, and consists of exploring the phase trend of each pixel as a function of the different central carrier frequencies. The phase of stable scatterers evolves linearly with the sub-band central wavelength, with a slope proportional to the absolute e.m. path difference. The technique appears optimally suited for the new generation of satellite sensors, which operate with larger bandwidths than previously available instruments, generally limited to few tens of MHz. A first experiment on satellite data was carried out by processing a spotlight interferometric pair of images acquired by TerraSAR-X on the well-known Uluru monolith in Australia. In the present work, we illustrate MCA processing on SAR data acquired over the same site by the COSMO-SkyMed constellation. The topographic profile of the monolith is successfully reconstructed. Furthermore, the results are also compared with those previously derived by processing TerraSAR-X data.
    Work supported by ASI under the AO-COSMO Project ID-1820, Contr. N I/047/09/0.

  • [Nit.SPIE2012] D. O. Nitti, F. Bovenga, A. Morea, F. M. Rana, L. Guerriero, M. Greco, G. Pinelli, "On the use of SAR interferometry to aid navigation of UAV". Proc. SPIE 8532, Remote Sensing of the Ocean, Sea Ice, Coastal Waters, and Large Water Regions 2012, 853203 (October 19, 2012). DOI:10.1117/12.974563. ISSN: 0277-786X. ISBN: 9780819492722. Scopus: 2-s2.0-84887047598. WOS:000312874500003
    This study is aimed at exploring the potentials of SAR Interferometry (InSAR) to aid Unmanned Aerial Vehicles (UAV) navigation. The basic idea is to infer both position and attitude of an aerial platform by inspecting the InSAR phase derived by a real time SAR interferometer mounted onboard the platform. Thanks to the expected favorable conditions in terms of geometrical sensitivity as well as signal coherence, the InSAR phase field can be used to derive the terrain elevation. By using both approximated position and attitude values of the platform as well as a reference Digital Terrain Model (DTM) from a mission database available onboard, it is possible to generate a synthetic InSAR phase model to be compared w.r.t. that derived by SAR observations. The geometrical transformation needed to match these two terrain models depends on the difference between position and attitude values derived by the instruments available on board and their actual values. Hence, this matching provides a feedback to be used for adjusting position and attitude. In order to assess the reliability of the proposed approach, we evaluated the interferometric sensitivity to changes in position and attitude. This analysis defines the limits of applicability of the InSAR-based approach and provides indications and requirements on geometric and radiometric parameters.
    The authors acknowledge the support of the SARINA project A-0932-RT-GC, which is coordinated by the European Defence Agency (EDA) and funded by 10 contributing Members (Cyprus, France, Germany, Greece, Hungary, Italy, Norway, Poland, Slovakia, Slovenia and Spain) in the framework of the Joint Investment Programme on Innovative Concepts and Emerging Technologies (JIP-ICET).

  • [Bov.SPIE2012] F. Bovenga, L. Gallitelli, D. O. Nitti, "Multi-chromatic analysis of a single SAR image for absolute ranging". Proc. SPIE 8536, SAR Image Analysis, Modeling, and Techniques XII, 853604 (November 21, 2012); DOI:10.1117/12.973722. ISSN: 0277-786X. ISBN: 9780819492760. Scopus: 2-s2.0-84875636236. WOS:000317134300003
    The Multi-Chromatic Analysis (MCA) uses interferometric pairs of SAR images processed at range sub-bands located at different spectrum positions, and explores the phase trend of each pixel in the frequency domain. The phase of stable scatterers evolves linearly with the sub-band central wavelength, the slope being proportional to the absolute optical path difference. Consequently, both phase uwrapping and height computation can be performed on a pixel by pixel basis without spatial integration. Recently the technique has been used to derive ground elevation by processing interferometric pairs acquired in Spotlight mode by both TerraSAR-X and COSMO-SkyMed satellite missions. However, further potential applications are possible. In particular, this work is aimed at experimenting the use of MCA for measuring the optical path between the SAR sensor and the scene by processing a single SAR acquisition. In this configuration, the slope of the phase trend along frequencies depends on the full optical path. In order avoid aliasing, we adopted a processing scheme which consists in subtracting from the SAR image phase a term proportional to the distance computed through inverse geocoding. Assuming negligible the positioning errors, the validation of this approach can be performed by comparing the distance measured by MCA with the atmospheric delay computed through analytical models. We carried out a feasibility study aimed at evaluating the maximum value for the errors in satellite and target positions, allowed to perform the reliable validation. Then, in order to reduce the error in the target positions and to guarantee good phase stability, we selected SAR acquisitions which include artificial corner reflectors to be used for MCA processing and the following validation procedure. We present results obtained by exploiting two corner reflectors visible within two TerraSAR-X images acquired in Spotlight mode over Venice Lagoon.
    TerraSAR-X data are provided by DLR (c) in the frame of the TerraSAR-X General AO Project MTH0432. Authors thank Davide Oscar Nitti from GAP srl to assist in gecoding processing.

  • [Rad.MIMOS2012] F. Radicioni, A. Stoppini, R. Brigante, G. Fornaro, F. Bovenga, D. O. Nitti, "InSAR, GNSS and leveling comparison on multi-annual series for the study of landslide surface deformation". Proceedings of MIMOS. October 9-11, 2012. Campus Universitario Tor Vergata, Roma. ISBN: 9788890764202 (presentation available at: http://lnx.mimos.it/mimos_decennale/Proceedings/SicurezzaTerritorio_08_Stoppini.pdf).
    A relevant part of the Assisi urban area (central Italy), built up after 1950 and located outside of the ancient town center, is interested by a landslide characterized by a rather slow rate of movement, which has caused important damages to buildings for an accumulation effect in the years. The movements of the soil surface have both a horizontal and a vertical component. For the monitoring of the landslide behaviour, the determination of the motion field and its evolution in time, a precision GNSS network has been established over the area since 1995, connecting by means of a baseline network the moving area with stable geologic formations located well outside (up to some km distance) of the landslide body. Further (1999), a leveling network has been added to improve the definition of the vertical component of the motion field. Surveys of both GNSS and leveling networks have been carried out in time, with an approximately annual cadence, until the actuality. Time series of coordinates and heights spanning along the observation period (1995-2010) are hence available for the network points. The Assisi landslide area has also been investigated by means of InSAR: the data here presented derive from the analysis of Envisat data spanning in time from 2003 to 2010, thus with a 7-years overlapping with the GNSS and leveling surveys, which make possible a comparison. SAR data refer to scatter points which are numerous and well spread over the landslide area but almost never coinciding with the GNSS and leveling markers. Moreover, the type of movements which can be put into evidence are different: along an assigned direction (the LOS, Line Of Sight) from the SAR data, in 3 dimensions from GNSS, along the vertical direction from leveling. This paper presents a comparison of the SAR results with the GNSS data, from which the LOS component has been derived. The comparison has been made for each GNSS marker with the surrounding SAR scatters, trying to take into account local topological effects when possible. This paper also presents results of the comparison between InSAR and leveling data, which requires a different approach, considering the different one-dimensional components of the movement given by leveling (along the vertical) and InSAR (along the LOS)
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  • [Ves.IGARSS2012] F. Vespe, L. Baldini, C. Benedetto, M. T. Chiaradia, C. Iasio, A. Losurdo, C. Notarnicola, C. Prati, D. Riccio, "X-SAR Cosmo-SkyMed mission and its scientific applications in the field of earth's observations: Some topics concerning the combinations of the observations achieved with other techniques". Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 22-27, 2012. Munich, Germany. DOI: 10.1109/IGARSS.2012.6352355. ISSN : 2153-6996. E-ISBN : 978-1-4673-1158-8. Print ISBN: 978-1-4673-1160-1.
    The Italian Space Agency (ASI Agenzia Spaziale Italiana) funded 27 scientific projects in the framework of COSMOSkyMed (CSK) program. A subset of them focused on the improvements of the quality and quantity of information which can be extracted from X-SAR data if integrated with other independent techniques (GPS, data and imagery in other bands and wavelengths). The paper summarizes the results obtained from same of these projects and, in particular, regarding: (1) the use of GPS observations and Numerical Weather Models (NWM) to remove atmospheric artifacts from InSAR imagery so improving the CSK potentialities in the field of topographic mapping; (2) the integration of SAR data in X, L and s to improve snow cover monitoring and glaciers detection; (3) the use of X-SAR data to retrieve rain precipitation and its validation with radar observations; (4) the improvements of the focusing techniques.
    Scientific projects funded by the Italian Space Agency (ASI Agenzia Spaziale Italiana) in the framework of COSMOSkyMed (CSK) program.

National Conference Proceedings

  • [Nit.GOLD2012] D. O. Nitti, F. Bovenga, "Interferometric DEM generation from COSMO-SkyMED data: potentials and challenges". Proceedings of the 2012 IEEE GOLD Remote Sensing Conference, 4-5 June, 2012. Consiglio Nazionale delle Ricerche, Rome, Italy (available at http://ieee.uniparthenope.it/chapter/gold12.html). ISBN: 978-88-7431-668-7.
    The present study is aimed at investigating the potentialities of the COSMO/SkyMed (CSK) constellation of EO satellites equipped with X-band monostatic SAR sensors for ground elevation measurement through InSAR techniques.
    Work supported by ASI under contract n. I/063/09/0.

Conference Abstracts

  • [Nit.EGU2012] D. O. Nitti, R. Nutricato, F. Intini, F. Bovenga, M. T. Chiaradia, R. Pacione, F. Vespe, "On the use of Weather Models in the mitigation of atmospheric artifacts in X-band SAR interferometry". Abstracts proceedings EGU 2012, Vienna, Austria, 22 - 27 April 2012. Abstract ID-No: EGU2012-9872. eISSN: 1607-7962.
    High resolution numerical weather models (NWM) are being to play a role of increasing importance for atmospheric phase screen (APS) mitigation. Here we present preliminary investigations concerning the estimation of the atmospheric contribution to X-band InSAR phase fields through numerical weather modeling. We selected tandem-like pairs of Stripmap COSMO/SkyMED images acquired over Parkfield (California, USA) with short normal baselines, thus ensuring low sensitivity to elevation. By using a 30m SRTM DEM available for the area of interest, we generated differential phase fields, mainly related to the difference between atmospheric conditions at the times of the two acquisitions. The interferometric artifacts have been hence compared to independent estimates of the atmospheric phase delay introduced by both wet and dry the components of the troposphere, obtained through Regional Atmospheric Modeling System (RAMS), a finite-difference, primitive equation, three-dimensional mesoscale NWM originally developed at Colorado State University. RAMS is a prognostic model capable of simulating a wide range of atmospheric motions due to the use of a nested grid system. Incorporation of topographic features occurs through the use of a terrain-following vertical coordinate system, while turbulence is parameterized using Mellor and Yamada’s level 2.5 scheme, as modified by Helfand and Labraga for growing turbulence. In order to assess the impact of the boundary conditions, numerical simulations have been repeated by using GFS, ECMWF and NAM data (resolution: 0.5 deg, 0.25 deg and 12km respectively). A spin-up time exceeding 24h was necessary for ensuring a realistic computation of the atmospheric boundary layer depth. Finally, the 3D computation of the scaled-up refractive index and its integration along the Line-Of-Sight (LOS) of the SAR sensor was performed in order to estimate the two-way radar phase delay. The preliminary results confirm the indications coming from recent similar studies: weather models are good for the long wavelengths (>20 km) and for vertical stratification which depends on the hydrostatic component of the troposphere, while they cannot actually ensure a sub-centimetric accuracy in the estimation of the wet component, as instead required in X-band interferometry. Finally, we used the GPS daily RINEX available on the Parkfield area to infer the atmospheric Zenith Total Delay (ZTD) and validate the outcomes of the NWM. GPS data were processed at ASI/CGS by using the NASA/JPL GIPSY-OASIS II for data reduction. The Precise Point Positioning approach was applied fixing JPL fiducial-free satellite orbits, clocks and earth orientation parameters, IGS absolute phase center variations and estimating, with a cut-off angle of 7deg, site coordinates, station clock, phase ambiguities, ZTD and tropospheric gradients. ZTD and tropospheric gradients are modeled as random walk processes and estimated with a sampling rate of 5 minutes. Results show correlation between the values computed by NWM and GPS. Furthermore, the differences are not correlated with the topography thus suggesting that the main cause of the mismatches relies on the tropospheric turbulence. This further confirms our previous conclusions.
    Work supported by ASI (Agenzia Spaziale Italiana) in the framework of the AO-COSMO Projects ID-1462 “Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation Contract I/063/09/0” and ID-2103 “Advanced 2D and 3D focusing of COSMO/SkyMed SAR data Contract n. I/059/09/0”. GPS data have been analyzed by e-GEOS under ASI contract I-014-10-0.

  • [Chi.AGU2012] M. T. Chiaradia, R. Nutricato, D. O. Nitti, F. Bovenga, L. Guerriero, "Railway infrastructure monitoring with COSMO/SkyMed imagery and multi-temporal SAR interferometry". AGU Fall Meeting 2012 Abstract, NH13A-1597, San Francisco, California, USA, 3-7 Dec. 2012. http://abstractsearch.agu.org/meetings/2012/FM/sections/NH/sessions/NH13A/abstracts/NH13A-1597
    For all the European Countries, the rail network represents a key critical infrastructure, deserving protection in view of its continuous structure spread over the whole territory, of the high number of European citizens using it for personal and professional reasons, and of the large volume of freight moving through it. Railway system traverses a wide variety of terrains and encounters a range of geo-technical conditions. The interaction of these factors together with climatic, and seismic forcing, may produce ground instabilities that impact on the safety and efficiency of rail operations. In such context, a particular interest is directed to the development of technologies regarding both the prevention of mishaps of infrastructures, due to natural disasters and/or to terrorist attacks, and the fast recovery of their normal working conditions after the occurrence of accidents (disaster managing). Both these issues are of strategic interest for EU Countries, and in particular for Italy, since, more than other countries, it is characterized by a geo-morphological and hydro-geological structure complexity that increases the risk of natural catastrophes due to landslides, overflowings and floods. The present study has been carried out in the framework of a scientific project aimed at producing a diagnostic system, capable to foresee and monitor landslide events along railway networks by integrating in situ data, detected from on board sophisticated innovative measuring systems, with Earth Observation (EO) techniques. Particular importance is attached to the use of advanced SAR interferometry, thanks to their all-weather, day-night capability to detect and measure with sub-centimeter accuracy ground surface displacements that, in such context, can occur before a landslide event or after that movements. Special attention is directed to the use of SAR images acquired by COSMO/SkyMed (ASI) constellation capable to achieve very high spatial resolution and very short revisit and response time. In this context, a stack of 57 CSK stripmap images (pol.: HH; look side: right; pass direction: ascending; beam: H4-03; resolution: 3x3 m2) have been acquired from October 2009 to April 2012, covering the Calabria's Tyrrhenian coast, between the towns of Palmi and Reggio Calabria. The imaged area is of strategic importance since the two towns are connected by a stretch of the Tyrrhenian railway line, a fundamental line (as classified by RFI, the Italian Rail Network) belonging to the TEN-T network, i.e. the trans-european transport network defined since early '90 by the European Commission. Moreover, Calabria region is a challenging area where carrying on an analysis on weathering-related slope movements. In Calabria, on 2009the geo-hydrological crisis was so severe that the Italian Government had to declare the “state of emergency”. This paper concerns the processing of the CSK dataset performed through the SPINUA algorithm a Persistent Scatterers Interferometry technique originally developed with the aim of detection and monitoring of coherent targets in non- or scarcely urbanized areas. The displacement maps derived on the area of interest will be presented and commented with particular attention to the potential impact that such EO-based product can have on the railway networks monitoring.
    CSK images provided by ASI (Agenzia Spaziale Italiana) in the framework of the project “Landslide Monitoring and Mapping System - CAR-SLIDE” (PON 01 00536). Optical images provided by GoogleEarth and GoogleStreet. The authors would like to thank dr. J. Wasowski (CNR-IRPI, Bari, Italy) for helpful comments on the achieved results.

  • [Tij.AGU2012] K. Tijani, M. T. Chiaradia, L. Guerriero, G. Pasquariello, A. Morea, R. Nutricato, G. Preziosa, "Monitoring of urban air pollution from MODIS and AERONET Aerosol Optical Thickness (AOT) data". AGU Fall Meeting 2012 Abstract, A21C-0058, San Francisco, California, USA, 3-7 Dec. 2012.
    Air pollution, caused by fuel industries and urban traffic and its environmental impact, are of considerable interest to studies in air quality. In this paper, the monitoring of the air pollution over urban areas in Italy through Aerosol Optical Thickness (AOT) data retrieved from Moderate Resolution Imaging Spectroradiometer (MODIS) measurements is presented. The high spatio-temporal frequency of MODIS AOT products (twice per day at 470nm, 1km full resolution) demonstrates that this satellite can be potentially used to routinely monitor the air pollution over land, especially urban area, which is the main source of aerosol particles. In this work AOT data derived by MODIS from November 2010 to February 2011 (winter period) and from May 2011 to August 2011 (summer period) were compared with AOT measurements from 6 different Aerosol Robotic Network (AERONET) stations over Italy (Bari, Lecce, Roma, Ispra, Potenza, Etna). The statistical analysis shows a good agreement between the ground based AOT measurements and the values retrieved using space based sensors, as shown in Figure 1. For all the stations the mean error is negligible, with a correlation ranging from 0.725 (in the worst case) to 0.96 (see Table 1). Moreover, LANDSAT-panchromatic images were used to discriminate urban and rural areas, based on the typical finger-like projections of urban land uses. The results of this study will be presented and commented.
    This work was funded by Apulian Region in the framework of the ECOURB project. (Analisi e Modelli di inquinamento atmosferico e termico per sistemi di ECOlabeling URBano, 2009-2012).

  • [Bel.CeTeM2012] A. Belmonte, A. Refice, F. Bovenga, G. Pasquariello, R. Nutricato, "Interpolation and unwrapping of sparse-grid InSAR data". VII Riunione Annuale CeTeM-AIT sul Telerilevamento a Microonde: sviluppi scientifici ed implicazioni tecnologiche Bari, 4-5 dicembre 2012.
    Applications such as SAR interferometry [1] are increasingly used in “sparse” contexts, in which information about some geophysical parameters (e.g. millimetric terrain deformations) are only available over some of the imaged pixels, corresponding to stable objects [2]. In such cases, it is often necessary to adapt processing algorithms, developed and optimized for regular data grids, to work on sparse samples. One of such algorithms, at the basis of several InSAR processing chains, is the so-called phase unwrapping (PU), consisting of obtaining absolute phase values (i.e. defined over the whole real interval) from the corresponding principal values, i.e. limited to the interval. Recently, a method to reduce the unwrapping problem of a sparse-grid field to one corresponding to a regular grid, has been proposed [3], based on a preliminary nearest-neighbor interpolation step. The solution to the sparse problem is shown to be mathematically equivalent to that of a corresponding regular grid problem, properly derived from the former. The approach allows to employ existing algorithms for regular-grid PU, such as those based on network theory (e.g. the so-called Minimum Cost Flow, or MCF). In this work, stemming from an analysis of the above-mentioned methodology, giving as a solution an absolute phase significant only over the sampled pixels, we propose an alternate procedure, in which the principal phase interpolation step is based on algorithms more advanced than the simple nearest-neighbor scheme. Such interpolation can be performed over the unit-magnitude complex field obtained from the wrapped phase. In this way, the obtained wrapped phase field results more similar to the original, “physical” regular field from which the sparse samples have been obtained. In the case in which this latter field can be assumed to satisfy general conditions of smoothness and homogeneity [4], this allows to exploit at best such characteristics, and to have finally an absolute phase regular matrix more representative of the real data, and then more effective to use in the subsequent processing steps [5]. In the paper, several interpolators are considered, such as radial basis functions (RBF), as well as, more generally, Kriging [6], and their performances and application limits are evaluated in simulation, as a function of both the regularity conditions of the original sampled surface, and the sampling density.
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Other poster/slideshow presentations

  • [Was.EOSantorini2012] J. Wasowski, F. Bovenga, D. O. Nitti, R. Nutricato, "Investigating landslides and unstable slopes with C- and X-band PSI: current opportunities and challenges". International Forum on Satellite EO for Geohazard Risk Management, 21-23 May 2012. Santorini Convention Centre, Greece.
    Persistent Scatterers Interferometry (PSI) and other similar multi-temporal synthetic aperture radar differential interferometry (DInSAR) techniques are capable to provide wide-area coverage (thousands km2) and precise (mm-cm resolution), spatially dense information (from hundreds to over thousand measurement points/km2) on ground surface deformations. Furthermore, new application opportunities are emerging thanks to i) the greater data availability offered by recent launches of radar satellites, and ii) the improved capabilities of the new space radar sensors (X-band Cosmo-SkyMed, RADARSAT-2, TerraSAR-X) in terms of resolution (from 3 to 1 m) and revisit time (from 11 to 4 days for X-band acquisitions). This in turn implies more and better resolution information about ground surface displacements as well as improved landslide monitoring and slope instability investigation capabilities. The applicability of the multi-temporal DInSAR techniques to regional and localscale investigations of slow landslides has already been demonstrated in many studies. However, to foster a more profitable use of these techniques in landslide investigations additional progress needs to be made in our understanding of small ground surface deformations detected from SAR data and in their integration with ground-based information. Examples of PSI applications to landslide monitoring and slope instability detection in different geomorphological and climatic settings are presented to illustrate i) the potential of the technique to provide, under suitable conditions, valuable reconnaissance and site-specific information on slope surface deformations, ii) the challenges in inferring the exact cause(s) of slow displacements (mm-cm/year) commonly registered on radar targets and the risks of misinterpretation; iii) the utility of Google Earth tools for 3D visualization and preliminary analysis of PSI results. Finally, specific recommendations and guidelines are offered on how to mitigate limitations of PSI applied to landslide and slope instability investigations and how to avoid erroneous interpretations of ground deformation measurements obtained from SAR data.
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Peer-Reviewed Journal Articles

  • [Nit.TGRS2011] Nitti D.O., Hanssen R.F., Refice A., Bovenga F. and Nutricato R., “Impact of DEM-assisted coregistration on high-resolution SAR interferometry”. IEEE Transactions on Geoscience and Remote Sensing, vol. 49 (3): 1127-1143, March 2011. DOI: 10.1109/TGRS.2010.2074204. ISSN: 0196-2892. WOS:000287658000020. Scopus: 2-s2.0-79952039240. IF: 2.90 (Year: 2011 - Source: ResearchGate - http://is.gd/OYvz3D)
    Image alignment is a crucial step in synthetic apertureradar (SAR) interferometry. Interferogram formation requires images to be coregistered with an accuracy of better than a few tenths of a resolution cell to avoid significant loss of phase coherence. In conventional interferometric precise coregistration methods for full-resolution SAR data, a 2-D polynomial of low degree is usually chosen as warp function, and the polynomialbparameters are estimated through least squares fit from the shifts measured on image windows. In case of rough topography or long baselines, the polynomial approximation may become inaccurate, leading to local misregistrations. These effects increase with spatial resolution of the sensor. An improved elevation-assisted image-coregistration procedure can be adopted to provide better prediction of the offset vectors. This approach computes pixel by pixel the correspondence between master and slave acquisitions by using the orbital data and a reference digital elevation model (DEM). This paper aims to assess the performance of this procedure w.r.t. the “standard” one based on polynomial approximation. Analytical relationships and simulations are used to evaluate the improvement of the DEM-assisted procedure w.r.t. the polynomial approximation as well as the impact of the finite vertical accuracy of the DEM on the final coregistration precision for different resolutions and baselines. The two approaches are then evaluated experimentally by processing high-resolution SAR data provided by the COnstellation of small Satellites for the Mediterranean basin Observation (COSMO/SkyMed) and TerraSAR-X missions, acquired over mountainous areas in Italy and Tanzania, respectively. Residual-range pixel offsets and interferometric coherence are used as quality figure.
    The authors would like to thank M. Arikan (TU Delft, The Netherlands) for the fruitful discussions on SAR coregistration and the anonymous reviewers for their valuable suggestions. The COSMO/SkyMed data were kindly provided by the Italian Space Agency (ASI) in the framework of theMORFEO project. The TerraSAR-X data (Infoterra) were kindly provided by Infoterra and acquired within the Study and Monitoring of Active African Volcanoes Project, coordinated by the Royal Museum for Central Africa in Belgium and National Museum of Natural History of Luxembourg.

  • [Rea.GRSL2011] D. Reale, D. O. Nitti, D. Peduto, R. Nutricato, F. Bovenga, G. Fornaro, “Post-seismic Deformation Monitoring With The COSMO/SKYMED Constellation”. IEEE Geoscience and Remote Sensing Letters, vol. 8 (4): 696-700, July 2011. DOI: 10.1109/LGRS.2010.2100364. ISSN: 1545-598X. WOS:000292105300023. Scopus: 2-s2.0-79959691919. IF: 1.56 (Year: 2011 - Source: ResearchGate - http://is.gd/PiwToa)
    COSMO/SKYMED is currently the unique constellation of synthetic aperture radar (SAR) sensors operative, which is also for civilian use. On April 6, 2009, an Mw 6.3 earthquake struck the city of l’Aquila in Central Italy. The constellation acquired data stacks over the hit area at an unprecedented temporal rate. In this letter, the results obtained by processing several data set via two independent multitemporal differential interferometric SAR techniques are presented to demonstrate the capability of this constellation in postseismic deformations monitoring.
    The authors would like to thank N. D’Agostino (INGV) for the support in the result interpretation and L. Candela (ASI) and B. De Bernardinis (DPC) for the support to the COSMO data access. The work was carried out under the ASI Contract I/045/07/0 "MOnitoraggio del Rischio da Frana mediante dati EO (MORFEO)."

  • [Mat.IJRS2011] R. Matarrese, M. T. Chiaradia, K. Tijani, A. Morea, R. Carlucci, "'Chlorophyll a' multi-temporal analysis in coastal waters with MODIS data". Italian Journal of Remote Sensing - 2011, 43 (3): 39-48. DOI: 10.5721/ItJRS20114333. Scopus: 2-s2.0-84857762251. WOS:000302401300004. ISSN: 1129-8596. IF: 0.47 (Year: 2011 - Source: https://goo.gl/x5icVo)
    The availability of a nearly-continuous remotely-sensed chlorophyll ‘a’ maps (Chl a) from MODIS sensor, now longer than ten years, enables the assessment of multi-temporal trends for several locations around the world. In this paper the statistical method of the Support Vector Machine (SVM) has been applied to 5 years of MODIS data in order to generate Chl a maps. A Chl a multi-temporal analysis of Apulian region coastal zones in Southern Italy shows a positive trend in two test cases, confirming the increase of productivity in Southern Adriatic region found in the last years and demonstrating the simplicity and usefulness of this technique.
    The research activity has been carried out in the framework of IMCA project (Integrated Monitor of Coastal Areas). Authors wish to thank the anonymous referees for their kind efforts and helpful comments.

International Conference Proceedings

  • [Bov.FRINGE2011] F. Bovenga, D. O. Nitti, A. Ganas, K. Chousianitis, "Co-seismic deformation due to the Tohoku-Oki Earthquake measured by Envisat-ASAR data and GPS". Proceedings of the Workshop Fringe 2011 - Advances in the Science and Applications of SAR Interferometry from ESA and 3rd party missions, September 19-23, 2011, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-697. ISBN 978-92-909226-1-2. ISSN 1609-042X.
    On March 11th, 2011, 05:46 UTC, a giant earthquake of magnitude Mw=9.0 occurred off the Pacific coast of Tohoku, Honshu Island, Japan. Massive damage has been reported, mainly related to the subsequent tsunami. In this work we present first results concerning the displacement induced by the Tohoku-oki earthquake by using ASAR ENVISAT data acquired few days before and after the event. The work points out the reliability of ASAR ENVISAT data to provide interferometric-based displacement field even though the satellite is recently came into a new operative phase with degraded orbital control and SAR data were processed in an emergency framework soon after the acquisition without precise orbital records. After removing artefacts due to strong orbital errors, the interferometric deformation pattern is mainly related to the coseismic displacement and it results comparable to that provided by the GEONET GPS network which has an unique density of in situ measurements found elsewhere in the world.
    Preliminary GPS time series provided by the ARIA team at JPL and Caltech. All original GEONET RINEX data provided to Caltech by the Geospatial Information Authority (GSI) of Japan. ENVISAT data are provided by ESA through the GEO Geohazards Supersite (http://supersites.earthobservations.org).

  • [Was.FRINGE2011] J. Wasowski, F. Bovenga, D. O. Nitti, R. Nutricato, T. Dijkstra And X. Meng, "PSI helps to map relative susceptibility to ground and slope instabilities in the Lanzhou loess area of Gansu Province, China". Proceedings of the Workshop Fringe 2011 - Advances in the Science and Applications of SAR Interferometry from ESA and 3rd party missions, September 19-23, 2011, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-697. ISBN 978-92-909226-1-2. ISSN 1609-042X.
    The PSI (Persistent Scatterer Interferometry) processing of ENVISAT ASAR data (period 2003-2010) provided spatially dense information (more than 400 PS/km2) on ground surface displacements in Lanzhou, capital of Gansu Province, NW China. The geomorphological and geological context of the local Yellow River valley indicate that the lower, flat areas with floodplain and valley-fill deposits (Holocene terraces with mainly reworked loess at the surface) are stable, whereas some higher, gently sloping valley sides appear locally unstable, particularly where the Late Pleistocene terraces are covered by young aeolian (Malan) loess. The PS velocity data suggest that the relative susceptibility to ground and slope instabilities is the highest on the 4th and 5th order river terraces. This is consistent with the presence of collapsible Malan loess and recent land use of these terraces involving irrigation and construction
    ENVISAT images were provided by ESA in the framework of CAT-1 project #7444 “Exploitation of ENVISAT radar data for ground and infrastructure instability hazard assessments in the Lanzhou area (Gansu Province, China)", PI - J. Wasowski. We also thank Jianjun, Xiao Li, Runqiang and Yating who helped in the field reconnaissance.

  • [Bov.FRINGE2011b] F. Bovenga, V. M. Giacovazzo, A. Refice, D.O. Nitti, N. Veneziani, "Interferometric multi-chromatic analysis of high resolution X-band data". Proceedings of the Workshop Fringe 2011 - Advances in the Science and Applications of SAR Interferometry from ESA and 3rd party missions, September 19-23, 2011, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-697. ISBN 978-92-909226-1-2. ISSN 1609-042X.
    The Multi-Chromatic Analysis (MCA) consists of performing sub-bands splitting in range frequency domain, thus generating chromatic views of lower range resolution, centered at different carrier frequencies. Multi-chromatic interferograms can be then generated by coupling chromatic views coming from an interferometric pair of SAR images. The interferometric phase of spectrally-stable scatterers evolves linearly with the sub-band central frequency, the slope being proportional to the absolute optical path difference. Unlike the standard “monochromatic” InSAR approach, this new technique allows performing spatially independent and absolute phase unwrapping (PU). Potential applications for the study of spectrally-stable targets include topographic measurements, atmospheric research or urban monitoring. The technique appears optimally suited for new-generation, wide-band, high-resolution satellite SAR sensors. This work presents first successful applications of the technique using both TerraSAR-X (TSX) and COSMO/SkyMed (CSK) spotlight data. In particular, we provide results concerning the use of MCA for performing absolute PU as well as for height measurement on a pixel-by-pixel basis. Moreover, the impact of coregistration procedure on the MCA-based inference is investigated.
    Work supported by both ESA ESTEC Contr. N. 21319/07/NL/HE and ASI Contr. I/047/09/0. COSMO/SkyMed data provided by ASI under the AO-COSMO Project ID-1820. TerraSAR-X data over Ayers Rock are made freely available by InfoTerra (http://www.infoterra.de/tsx/freedata/start.php)

National Conference Proceedings

  • [Amo.POLEMIO2011] G. Amoruso, G. Tedeschi, R. Corbino, F. Intini, "Monitoraggio meteoclimatico finalizzato ad attività di Protezione Civile (previsione, prevenzione e allertamento) nel tempo reale e ad attività di pianificazione nel tempo differito", Atti delle Giornate di Studio "Impatto delle modificazioni climatiche su rischi e risorse naturali. Strategie e criteri d'intervento per l'adattamento e la mitigazione", Bari, Aula Magna del Dipartimento di Geologia, 10-11 Marzo 2011. In: “Le modificazioni climatiche e i rischi naturali”. Polemio M. (Ed.), ISBN 9788890508806, CNR IRPI, Bari, 2011.
    La disponibilità di una serie storica di dati termopluviometrici, rilevati dalla rete regionale di misura al suolo, ha permesso di realizzare mappe climatiche regionali, ottenute con tecniche geostatistiche (kriging), relative al trentennio 1976-2005. Al fine di porre in atto misure di mitigazione nelle aree ad elevato rischio idraulico, il Centro Funzionale Regionale ha potenziato la rete di monitoraggio. Nuovi sensori idrometrici sono stati installati sul bacino interregionale del fiume Fortore che, negli ultimi anni, è stato ripetutamente interessato da eventi meteorologici avversi che hanno coinvolto la Protezione Civile regionale nella gestione delle relative situazioni di criticità.
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  • [Bar.SPATIAL2011] E. Barca, G. Passarella, A. Morea, "A software for optimal information based downsizing/upsizing of existing monitoring networks". Proceedings of Workshop "Spatial Data Methods for Environmental and Ecological Processes". (SPATIAL2), Foggia, 1-3 September 2011. Ed. B. Cafarelli. Cdp Service Edizioni, CD ROM.
    Using reliable stochastic or deterministic methods, it is possible to rearrange an existing network by eliminating, adding or moving monitoring locations producing the optimal arrangement among any possible. In this paper, some spatial optimization methods have been selected as more effective among those reported in literature and implemented into a software M-Sanos able to carry out a complete redesign of an existing monitoring network. Both stochastic and deterministic methods have been embedded in the software with the option of choosing, case by case, the most suitable with regard to the available information. Finally, an application to the existing regional groundwater level monitoring network of the aquifer of Tavoliere located in Apulia (south Italy) is presented.
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Conference Abstracts

  • [Was.EGU2011] J. Wasowsky, F. Bovenga, D. O. Nitti, R. Nutricato, T. Dijkstra, X. Meng, "Detecting very slow ground movements using PS interferometry in the Lanzhou loess area of Gansu Province, China". Abstracts proceedings EGU 2011, Vienna, Austria, 03 - 08 April 2011. Abstract ID-No: EGU2011-11139. eISSN: 1607-7962.
    Ground instability monitoring and control traditionally rely on qualitative, often subjective geomorphological assessments and, where affordable, on relatively expensive in situ investigations. Due to limited opportunities for in situ instrumentation (cost, reliability and robustness) there is often a serious lack of monitoring data. Thenuse of PSI (Persistent Scatterer Interferometry) results, provides a welcome opportunity to test and calibrate bexisting slope deformation models against independent monitoring data. The advantages and limitations of PSI for ground instability detection and monitoring are evaluated for the semi-arid loess area of the city of Lanzhou (Gansu Province, China) home to over 3 million people. In this tectonically active region, ground instability in the loess and underlying bedrock is widespread and Lanzhou pays an increasingly high price due to lost lives and livelihoods as the city and its environs continue to develop in an unstable terrain. More than 40 ENVISAT ASAR datasets (period 2003-2010) were pre-processed to obtain stacks of co-registered differential SAR interferograms. Then the SPINUA algorithm was used to perform multi-temporal analysis on the co-registered DInSAR stacks in order to correct for spurious effects such as atmospheric artefacts and DEM error, and obtain precise displacement information over selected radar targets (PS). The analysis resulted in the identification of over 140,000 PS in the greater Lanzhou area (about 300 km2). The PSI displacement map of Lanzhou reveals several zones characterized by the presence of moving PS (with average velocities typically from a few mm/yr to several mm/yr). The optical image interpretation and first reconnaissance field checks indicate that we detected only a limited number of moving radar targets potentially indicative of unstable slopes. Instead, the majority of the detected moving persistent scatterers appear to be associated with local subsidence and settlement/structure instability processes. It may often be difficult to ascertain the exact origin of low strain rates, especially when these are detected on steep slopes, because these can arise from different causes (e.g. subsidence and local settlements, shallow seasonal creep, true slope/landslide movements, volumetric changes of geological/artificial materials, tectonics, and instability of structures that act as radar targets). Thus, ground truthing in the form of correlating displacements with information on local geology, geomorphology and slope history, as well as detailed in situ inspections is essential for the correct interpretation of any PSI displacement map.
    ENVISAT images were provided by ESA in the framework of CAT-1 project #7444 "Exploitation of ENVISAT radar data for ground and infrastructure instability hazard assessments in the Lanzhou area (Gansu Province, China)".

  • [Chi.AGU2011] M. T. Chiaradia, D. O. Nitti, F. Bovenga, F. Intini, R. Nutricato, K. Tijani, "On the COSMO-SkyMed Exploitation for Interferometric DEM Generation". AGU Fall Meeting Abstract, EP41A-0574, San Francisco, California, USA, 5-9 Dec. 2011. http://abstractsearch.agu.org/meetings/2011/FM/sections/EP/sessions/EP41A/abstracts/EP41A-0574
    DEM products for Earth observation space-borne applications are being to play a role of increasing importance due to the new generation of high resolution sensors (both optical and SAR). These new sensors demand elevation data for processing and, on the other hand, they provide new possibilities for DEM generation. Till now, for what concerns interferometric DEM, the Shuttle Radar Topography Mission (SRTM) has been the reference product for scientific applications all over the world. SRTM mission [1] had the challenging goal to meet the requirements for a homogeneous and reliable DEM fulfilling the DTED-2 specifications. However, new generation of high resolution sensors (including SAR) pose new requirements for elevation data in terms of vertical precision and spatial resolution. DEM are usually used as ancillary input in different processing steps as for instance geocoding and Differential SAR Interferometry. In this context, the recent SAR missions of DLR (TerraSAR-X and TanDEM-X) and ASI (COSMO-SkyMed) can play a promising role thanks to their high resolution both in space and time. In particular, the present work investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. The recent scientific works, [2] and [3], have shown the advantages of using CSK in the monitoring of terrain deformations caused by landslides, earthquakes, etc. On the other hand, thanks to the high spatial resolution, CSK appears to be very promising in monitoring man-made structures, such as buildings, bridges, railways and highways, thus enabling new potential applications (urban applications, precise DEM, etc.). We present results obtained by processing both SPOTLIGHT and STRIPMAP acquisitions through standard SAR Interferometry as well as multi-pass interferometry [4] with the aim of measuring ground elevation.
    Work supported by ASI (Agenzia Spaziale Italiana) in the framework of the project “AO-COSMO Project ID-1462 - Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation - ASI Contract I/063/09/0”.

  • [Nut.GEOITALIA2011] R. Nutricato, D. O. Nitti, F. Bovenga, M. T. Chiaradia, "On the COSMO-SkyMed Exploitation for Interferometric DEM Generation". Epitome of GeoItalia 2011, VIII Forum Italiano di Scienze della Terra, Turin, Italy, 19-23 Sept. 2011. ISSN 1972-1552.
    DEM products for Earth observation space-borne applications are being to play a role of increasing importance due to the new generation of high resolution sensors (both optical and SAR). These new sensors demand elevation data for processing and, on the other hand, they provide new possibilities for DEM generation. Till now, for what concerns interferometric DEM, the Shuttle Radar Topography Mission (SRTM) has been the reference product for scientific applications all over the world. SRTM mission [1] had the challenging goal to meet the requirements for a homogeneous and reliable DEM fulfilling the DTED-2 specifications. However, new generation of high resolution sensors (including SAR) pose new requirements for elevation data in terms of vertical precision and spatial resolution. DEM are usually used as ancillary input in different processing steps as for instance geocoding and Differential SAR Interferometry. In this context, the recent SAR missions of DLR (TerraSAR-X and TanDEM-X) and ASI (COSMO-SkyMed) can play a promising role thanks to their high resolution both in space and time. In particular, the present work investigates the potentialities of the COSMO/SkyMed (CSK) constellation for ground elevation measurement with particular attention devoted to the impact of the improved spatial resolution wrt the previous SAR sensors. The recent scientific works, [2] and [3], have shown the advantages of using CSK in the monitoring of terrain deformations caused by landslides, earthquakes, etc. On the other hand, thanks to the high spatial resolution, CSK appears to be very promising in monitoring man-made structures, such as buildings, bridges, railways and highways, thus enabling new potential applications (urban applications, precise DEM, etc.). Both SPOTLIGHT and STRIPMAP acquisition modes are analyzed through standard SAR Interferometry as well as multi-pass interferometry [4]
    Work supported by ASI (Agenzia Spaziale Italiana) in the framework of the project "AO-COSMO Project ID-1462 - Feasibility of possible use of COSMO/SkyMed in bistatic SAR Earth observation - ASI Contract I/063/09/0".

  • [For.WLF2011] G. Fornaro, D. O. Nitti, R. Nutricato, F. Bovenga, D. Peduto, L. Cascini, "Technological and Methodological Advances in the Application of Spaceborne DInSAR for Landslide Monitoring". Abstract n. WLF2 - 2011- 0516 in: "Catani F., Margottini C., Trigila A., Iadanza C. (eds) 2011. The Second World Landslide Forum - Abstract Book, 3-9 October 2011, FAO, Rome, Italy, ISPRA. ISBN 978-88-448-0515-9".
    Multipass Differential Interferometry Synthetic Aperture Radar (DInSAR) is today a well established technique for ground deformation monitoring in many areas of natural risk analysis. Compared to classical geodetic techniques such as leveling and GPS it provides advantages in terms of costs, coverage, data accessibility and availability of data archives. Application to different areas of the risk management such as monitoring of volcanoes, tectonic movements, urban areas and infrastructure and slope instabilities, has been already successfully demonstrated. As far as the landslide monitoring is concerned, the monitoring of surface deformation via the DInSAR technique may provide useful information regarding the spatial and temporal distribution of slow moving landslides and their kinematics characteristics. However, among all the DInSAR applications, landslides monitoring is particularly critical due to the presence of vegetation and to the occurrence of the phenomena in areas typically characterized by slope variations. Accordingly, the interpretation of the measurements can be affected by variations of the direction of the surface movement as well as of geometric distortions induced by the topography variations. Classical applications of the DInSAR techniques has been carried out in the past on medium resolution data acquired by the ERS, Envisat and Radarsat sensors. The new generation of high-resolution X-Band SAR sensors, such as TerraSAR-X and the COSMO-SkyMed constellation allows acquiring data with spatial resolution reaching metric/submetric values. Thanks to the finer spatial resolution with respect to data, X-band InSAR applications appear very promising for monitoring single man-made structures, also isolated, thus giving more chances to provide displacement records for landslide investigation in particular where data show low density of coherent scatterers. This work aims to describe the advances in terms of methodological development for the interpretation of DInSAR measurements for landslide monitoring and to provide a “view” on the improvements associated with the new generation high resolution SAR sensors. In particular a DInSAR data interpretation approach based on the joint use of remote sensed data and simplified geomorphological models is discussed. This procedure, tested via the application of a Small BAseline Subset (SBAS) (two-scale analysis) approach to data acquired by the medium resolution satellites, allows the estimation of the vector ground displacement, thus improving the result interpretation. Furthermore, the recent results of the application of a Persistent Scatterers Interferometry technique, namely the SPINUA (Stable Point INterferometry over Unurbanized Areas) algorithm, to data acquired by the COSMO-SKYMED satellite constellation in areas of the Italian territory are presented
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  • [Nut.WLF2011] R. Nutricato, J. Wasowski, F. Bovenga, A. Refice, G. Pasquariello, D. O. Nitti, M. T. Chiaradia, "C/X-band interferometry applied to slope instability monitoring in the Daunia mountains, Italy". Abstract n. WLF2 - 2011- 0552 in: "Catani F., Margottini C., Trigila A., Iadanza C. (eds) 2011. The Second World Landslide Forum - Abstract Book, 3-9 October 2011, FAO, Rome, Italy, ISPRA. ISBN 978-88-448-0515-9".
    Thanks to the all-weather, day-night capability to detect and quantify accurately small ground surface deformations, Synthetic Aperture Radar (SAR) Interferometry (InSAR) techniques are attractive for landslide hazard investigations. In particular, multi-temporal InSAR techniques allow to detect and monitor millimetric displacements occurring on selected point targets exhibiting coherent radar backscattering properties (mainly buildings and other man-made structures). In the present work we apply the SPINUA (Stable Point INterferometry over Un-urbanised Areas) multi-temporal processing technique [1] to the Daunia region located in Southern Apennines, Italy. This region includes several small hill-top towns affected by slope instability problems and is of particular interest for the Civil Protection – Regione Puglia Authority, which is one of the end users of the deformation maps derived by multi-temporal interferometric analysis of satellite data. This site was already investigated in the past though interferometric analysis [2] by using ERS-1/2 SAR data provided by ESA. In this work we present results obtained by processing SAR data acquired by the ENVISAT ESA satellite (, medium spatial resolution) as well as by the TerraSAR-X satellite (X-band high resolution) launched by DLR in 2007. Thanks to the finer spatial resolution with respect to data, X-band InSAR applications appear very promising for monitoring single man-made structures (buildings, bridges, railways and highways) as well as areas where data show low PS density. This is the case, in particular, of the Daunia region which is scarcely urbanised. Indeed, the results obtained with X-band data suggest that many more man-made and natural targets behave as persistent scatterers than in . Moreover, thanks again to the higher resolution, it should be possible to infer reliable estimates of the displacement rates with a number of SAR scenes significantly lower than in within the same time span or by using more images acquired in a narrower time span. Finally, with shorter wavelengths the sensitivity to LOS displacements is increased together with the capability of detecting very low displacements rates (as the pre- and post-failure movements related to landslides are expected to be). The displacements maps obtained by processing both C- and X-band SAR data will be presented for a selected number of towns affected by slope instability. Results will be commented with particular attention paid to the advantages provided by the new generation of X-band high resolution space-borne SAR sensors.
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  • [Int.RMSC2011] Franco Intini, G. Amoruso, M. T. Chiaradia, R. Corbino, Francesca Intini, G. Tedeschi, K. Tijani, “High Resolution Rams Implementation On Apulia Region And Forecast Fields Validation By Comparison With Ground Observations”. Royal Meteorological Society Conference 2011, University Of Exeter, Uk, 27-30 June 2011.
    A forecasting system has been implemented for operational forest fire hazard prediction over Apulia region (Italy) in the framework of an agreement between Geophysical Applications Processing (Polytechnic of Bari) and Apulia Region Civil Protection. The modelling chain, composed of a limited area model for weather forecasting and a model based on Fire Weather Index, has been executed during the whole summer season June-September 2009 and validated by comparison with available meteorological observations and fire occurrence data. In this paper the validation results of weather forecasting module are presented. Atmospheric fields prediction has been performed by the Regional Atmospheric Modeling System (RAMS), in a two nested grids configuration with the inner grid resolution at 4km. The atmospheric boundary and initial conditions were obtained from GFS data available every 6h with 0.5° resolution. Vertical discretization consisted of a 30-level stretched vertical coordinate with a 50m spacing near the surface increasing gradually up to 1200m near the model top at 19000m. The Kuo convective parameterization scheme has been activated on both grids and the full package for microphysics has been used with a single-moment bulk scheme. In the present work the validation of precipitation and temperature forecast fields is discussed. The validation criteria were based on the comparison with rain gauges and thermometer observations: in both cases measurements from regional Civil Protection thermo-pluviometric monitoring network have been employed. The tests conducted show a generally satisfactory RAMS model performance and forecast values in a good agreement with ground measurements. Currently, there is a sperimentation (in the context of recent research projects funded by Italian Space Agency) of further applications of the model with reference to atmospheric correction estimation in the development of advanced processing techniques for focusing of COSMO-SkyMed data and interferometric DEM generation.
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International Conference Proceedings

  • [Bov.SPIE2010] F. Bovenga, D. O. Nitti, A. Refice, R. Nutricato, M. T. Chiaradia, “Multi-temporal DInSAR analysis with X-band high resolution SAR data: examples and potential”. In Proceedings of SPIE Remote Sensing, 20-23 September 2010, Toulouse, France. DOI: 10.1117/12.866459. ISBN: 9780819483461. ISSN 0277-786X. Scopus: 2-s2.0-78649743122. WOS:000287758300013
    The recent availability of wide-bandwidth, high-frequency, high-resolution SAR data is contributing to improved monitoring capabilities of spaceborne remote sensing instruments. In particular, the new COSMO/SkyMed (CSK) and TerraSAR- X (TSX) X-band sensors allow better performances in multitemporal DInSAR and PSI applications than legacy sensors such as ENVISAT ASAR, with respect to both target detection and terrain displacement monitoring capabilities. In this paper we investigate about the possibility of achieving performances of PSI displacement detectioncomparable to those of sensors, by use of reduced numbers of high-resolution X-band . To this end, we develop a simple model for phase and displacement rate measurement accuracies taking into account both target characteristics and sensors acquisition schedule. The model predicts that the generally better resolution and repeat-time characteristics of new-generation X-band sensors allow reaching accuracies comparable to data with a significantly smaller number of X-band acquisitions, provided that the total time span of the acquisitions is large enough. This allows in principle to contain the costs of monitoring campaigns, by using less scenes. Indications are more variable in the case of short-time acquisition schedules, such as those involved in the generation of so-called “rush products” for emergency applications. In this case, the higher uncertainty given by shorter total time spans lowers X-band performances to levels mostly comparable to those of the legacy medium-resolution sensors, so that no significant gain in image number budget are foreseen. These theoretical results are confirmed by comparison of three PSI datasets, acquired by ENVISAT ASAR, CSK and TSX sensors over Assisi (central Italy) and Venice.
    The authors are grateful to Claudia Notarnicola (EURAC-Institute of Applied Remote Sensing, Bolzano, Italy) for the fruitful collaboration. ENVISAT and COSMO-SkyMED images are provided respectively by ESA and ASI in the framework of the MORFEO project (ASI Contract n. I/045/07/0). TerraSAR-X data ((c) Infoterra) are provided by Info-terra within the TerraSAR-X General AO Project MTH0432 (PI Maria Teresa Chiaradia).

  • [Bov.IGARSS2010] F. Bovenga, L. Candela, F. Casu, G. Fornaro, F. Guzzetti, R. Lanari, D. O. Nitti, R. Nutricato and D. Reale, “The COSMO-SkyMED constellation turn on the l’Aquila earthquake: DInSAR results of the MORFEO project.”. In Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 25-30, 2010. Honolulu, Hawaii, USA. DOI: 10.1109/IGARSS.2010.5654016. ISSN: 2153-6996. E-ISBN: 978-1-4244-9564-1. Print ISBN: 978-1-4244-9565-8. ISSN: 2153-6996. eISSN: 2153-7003. Scopus: 2-s2.0-78650879901. WOS: 000287933804246
    On April 6th 2009 a Mw=6.3 earthquake struck the area around the city of L’Aquila in Italy. SAR systems have been proven to be valuable sensors for analyzing the effect of earthquakes and monitoring post-seismic displacements. Due to the low deformation rate, the study of post-seismic events requires the use of a multi-temporal InSAR approach. COSMO/SKYMED is a constellation of SAR sensors of 4 X-band sensors operative also for the civilian use. Thanks to the availability of a stack of ascending acquisitions, ad hoc programmed by ASI on the area stricken by the earthquake, it was possible to provide postseismic deformation maps by using two different multitemporal interferometric approaches: the SPINUA and SBAS techniques. The work is carried out in the framework of the MORFEO project dedicated to the monitoring of the landslides risk by means of Earth Observation data. The displacement maps related to the post-seismic activity are presented and commented. The results clearly show the potentiality of the COSMO/SKYMED constellation use for emergency monitoring.
    The authors are grateful to the Italian Civil Protection Department, and particularly to Prof. De Bernardinis for the support. This work was supported by ASI, under Contract No. I/045/07/0 “MOnitoraggio del Rishio da Frana mediante dati EO (MORFEO)”.

  • [Bov.LIVINGPLANET2010] F. Bovenga, D. O. Nitti, R. Nutricato and M. T. Chiaradia, “C- and X-band multi-pass InSAR analysis over Alpine and Apennine regions”. In Proceedings of the European Space Agency Living Planet Symposium, June 28 - July 2, 2010, Bergen, Norway. Vol. ESA SP-686. ISBN 978-92-9221-250-6. ISSN 1609-042X.
    In the present work we present results of ground defor-mation measurements inferred through repeat-pass Syn-thetic Aperture Radar (SAR) Interferometry (InSAR) in C- and X-band over Alpine and Apennine sites affected by slope instability. The activity was carried out in the framework of the MORFEO (MOnitoraggio e Rischio da Frana mediante dati EO) project, founded by the Italian Spatial Agency (ASI) and dedicated to landslide risk assessment. A number of areas affected by hydro-geological instabilities have been selected and studied in detail by processing both C- and X-band SAR data through multi-temporal Differential SAR Interferome-try algorithms. InSAR-derived displacements provided on areas of hy-drogeological interest are going to be validated in the framework of MORFEO project by the geological part-nership thanks to the availability of ground truths. In the present work, we present the results obtained by proc-essing through SPINUA, a PS-like algorithm, three ar-eas affected by landslide phenomena: the area around Garzeno and Catasco in the Lombard Alps, the area aver St. Moritz in the Swiss Alps and the Ivancich landslide close to Assisi town in the Italian Apennine. We provide comparison between the deformation maps derived from ENVISAT and those obtained by process-ing a limited number of COSMO-SkyMED images. Our results are also validated by using ERS and RADAR-SAT PS maps freely available on the GeoIFFI web-catalogue (Garzeno), geotechnical investigation avail-able in literature (St. Moritz) and results from SBAS technique (Assisi).
    ENVISAT and COSMO-SkyMED images were pro-vided respectively by ESA and ASI in the framework of the MORFEO project (ASI Contract n. I/045/07/0).

National Conference Proceedings

  • [Nut.ASITA2010] R. Nutricato, D. O. Nitti, M. T. Chiaradia, F. Bovenga, A. Refice, G. Pasquariello, “Rilevamento di deformazioni del suolo in Daunia (Puglia) per mezzo di tecniche interferometriche SAR”. Atti 14a Conferenza Nazionale ASITA, 9–12 Novembre 2010, Fiera di Brescia, Italia. ISBN: 9788890313257.
    In this paper we present the research activity carried out in the framework of a project funded by Puglia Region and aimed at using SAR Interferometry for measuring deformations induced by landslides in the Daunia region (Puglia). The area is of particular interest for the Civil Protection – Regione Puglia Authority which is one of the potential end users of the deformation map derived by multi-temporal interferometric analysis of satellite data. The results have been obtained through the SPINUA processing chain (Bovenga et al., 2004) which performs a multi-temporal InSAR Persistent Scatterer-like analysis. These approaches are able to inspect periodically a wide area on the ground measuring sub-vertical displacements with a precision of few millimetres per year for the mean velocity. The algorithm is also able to process the new generation of X-band high resolution SAR data. In the paper we present first results obtained by processing SAR data acquired between 2002 and 2010 by the ENVISAT ESA satellite which works at and medium spatial resolution.
    Le immagini sono state fornite dall’ESA nell’ambito del progetto CAT-1 id. 2653, “Advanced SAR Interferometry techniques for landslide warning management”.

  • [Bel.ASITA2010] V. Bellifemine, F. Bovenga, L. Candela, R. Nutricato, G. Pasquariello, A. Refice, "Identificazione di aree inondate da immagini SAR a media ed alta risoluzione", Atti 14a Conferenza Nazionale ASITA, 9-12 Novembre 2010, Fiera di Brescia, Italia. ISBN: 9788890313257.
    Obiettivo del lavoro è stato l’assessment di tecniche automatiche per l’estrazione di aree inondate da immagini SAR. Al fine di raggiungere tale obiettivo sono stati considerati i dati in banda X ad alta risoluzione spaziale (da 1 a 4 m.) della costellazione italiana COSMO-SkyMed. I casi di studio considerati sono stati: l’ esondazione del Dicembre 2009 del Lago di Massaciuccoli, in Toscana e gli eventi di piena relativi al Fiume Tanaro in Piemonte avvenuti negli ultimi giorni dell’Aprile 2009. L’approccio di change detection adottato si basa su una tecnica per la ricerca automatica della soglia sulle immagini delle intensità. Inoltre, lì dove erano disponibili coppie interferometriche con sufficiente correlazione, è stato verificato un approccio basato sulla segmentazione dell’immagine della correlazione interferometrica. Nel lavoro sono presentati i risultati e la valutazione sull’uso in situazioni di emergenza dove viene richiesta l’identificazione più precisa delle aree colpite per la valutazione dei danni e per programmare azioni di pronto intervento.
    Gli Autori ringraziano il Prof. Luciano Guerriero del Politecnico di Bari per gli utili suggerimenti ed il Dipartimento della Protezione Civile per il supporto fornito e la disponibilità dimostrata.

  • [Int.BOSCHI2010] F. Intini, K. Tijani, F. Intini, M. Zippitelli, L. Guerriero, G. Scarascia Mugnozza, "Tecniche modellistiche e satellitari per la previsione ed il monitoraggio del pericolo incendi in Puglia". Atti del Convegno "Previsione, prevenzione e lotta attiva agli incendi boschivi nella Regione Puglia", Facoltà di Agraria, Bari, Febbraio 2010.
    I sistemi per il monitoraggio e per la valutazione della pericolosità incendi sono di grande utilità per la lotta attiva agli incendi boschivi. Durante la campagna AIB 2009, il Servizio di Protezione Civile della Regione Puglia ha utilizzato, per la prima volta, in modalità sperimentale, un sistema di previsione della pericolosità incendi composto da un modello meteorologico prognostico non idrostatico RAMS (Regional Atmospheric Modelling System) e da un sistema di calcolo dell’indice canadese di pericolo di incendio FWI (Fire Weather Index). Il sistema modellistico, realizzato da Geophysical Applications Processing (GAP) srl, Spin Off del Politecnico di Bari, è stato implementato in modalità operativa dopo una verifica preliminare effettuata attraverso il confronto con i dati di osservazione raccolti durante la campagna AIB 2008. Il confronto effettuato con i dati registrati dal CFS (Corpo Forestale dello Stato) indica una corrispondenza pari al 77% tra gli incendi di maggiore estensione (> 20ha) avvenuti in aree boscate ed i valori di FWI appartenenti alle due classi più elevate. Uno dei principali vantaggi del sistema modellistico realizzato consiste nella produzione di mappe di previsione di FWI ad una risoluzione nettamente superiore a quella disponibile con altri sistemi analoghi e di mappe di previsione di parametri atmosferici utili alla lotta attiva agli incendi boschivi. La disponibilità in tempo reale di mappe satellitari MSG (Meteosat Second Generation) ha permesso, inoltre, di progettare e realizzare un sistema prototipale per la rilevazione dei fuochi attivi sul territorio pugliese.
    Lavoro realizzato nell'ambito della Convenzione tra la Regione Puglia - Servizio Protezione Civile e Geophysical Applications Processing (GAP) srl, Spin Off del Politecnico di Bari (Delibera della Giunta Regionale del 26 novembre 2008, n. 2294).

Conference Abstracts

  • [Guz.EGU2010] MORFEO Team, "Results of the MORFEO project: Exploiting remote sensing technology to detect, map, monitor, and forecast slope failures". European Geosciences Union General Assembly 2010, Vienna, Austria, 02–07 May 2010. Session NH3.4 Abstract ID-No: EGU2010-11871. eISSN: 1607-7962.
    Advances in space borne, airborne and terrestrial remote sensing technologies have improved our ability to identify, map, monitor, and forecast ground deformations, including landslides. In 2001, the Italian Space Agency (ASI) launched a multifaceted call for technological and scientific applications of remote sensing technology to help identify, monitor, forecast, and mitigate natural and manmade hazards, including slope failures. Following this call, in 2007, ASI lunched the MORFEO project, a coordinated research and development initiative aimed at the development and preliminary implementation of a prototype system to support the Italian National Civil Protection Department activities on landslide risk assessment and mitigation, at different spatial and temporal scales. MORFEO, an Italian acronym for Monitoring Landslide Risk through Earth Observation technology, is aimed at the synergic exploitation of Earth observation (EO) data and technologies, consolidated and innovative ground based monitoring tools, and existing and new thematic and environmental information, to improve the ability of the Italian National Civil Protection Department to promptly detect, map, monitor, and forecast landslides of different types, and in different physiographic environments. The MORFEO team is headed by Carlo Gavazzi Space (CGS), a leading European company in space technology, and by IRPI, a research institute of the Italian National Research Council leader in landslide investigations. CGS and IRPI are assisted by a unique multi-disciplinary teamcomprising research institutes, university departments and Italian enterprises collectively experts in landslide identification and mapping, slope monitoring, landslide and environmental hazard and risk assessment and mitigation, and in the innovative exploitation of EO data and technologies. MORFEO is characterized by a significant research component. Due to the difficulty inherent in the use of multiple satellite, airborne, and ground based EO technologies and information for landslide risk assessment and mitigation, executing innovative research is fundamental to the project. In this work, we report on the main research results obtained during the first two years of the project MORFEO.
    This work was supported by ASI, under Contract No. I/045/07/0 “MOnitoraggio del Rishio da Frana mediante dati EO (MORFEO)”.

  • [Was.EGU2010] J. Wasowski, C. Lamanna, D. Casarano, F. Bovenga, D.O. Nitti, R. Nutricato, F. Rana, G. Colangelo, “Interpreting very slow surface movements on slopes detected by PS interferometry and GPS surveying: case study from the Southern Apennines, Italy”, Abstracts proceedings EGU 2010, Vienna, Austria, 02 – 07 May 2010. Abstract ID-No: EGU2010-15380-1. eISSN: 1607-7962.
    Advanced multi-temporal DInSAR techniques (eg Persistent Scatterer Interferometry - PSI) can typically detect only very slow ground surface displacements (usually up to few cm/year). We argue that it may often be difficult to ascertain the exact origin of such movements, especially when they occur on hill slopes, because they can arise from different causes (eg subsidence and local settlements, shallow seasonal creep, true slope/landslide movements, volumetric changes of geological/artificial materials, tectonics, instability of structures that act as radar targets). We also draw attention to the practical limitations of PSI in the rural areas, where the density of potential radar targets is low. These difficulties are exemplified here with a case study from the Apennine mountains of southern Italy. Although this area, which includes Potenza, capital city of the Basilicata Region, has been known for its susceptibility to landsliding, PSI analysis based on over 30 ENVISAT ASAR ascending and descending acquisitions (covering 2003 to 2009) detected only a limited number of moving radar targets potentially indicative of instable slopes. Instead, the majority of the detected moving persistent scatterers can be associated with local subsidence and settlement/structure instability processes (with average velocities up to several and a few mm/yr, resp.). Nevertheless, one case of a large landslide re-activated in a rural area in 2006 shows that GPS surveying and PSI application, respectively, monitoring the points on the landslide and on nearby buildings, can furnish complementary information useful for the assessment of relative hazard. Thus, local knowledge (geology, geomorphology, slope history) and in situ inspections could often be essential for the correct interpretation of PSI displacement maps. Furthermore, note that the exploitation of both descending and ascending imagery — two independent analyses — not only offers the simplest form of reciprocal validation but also helps overcome interpretative difficulties linked to the 1-D nature of PSI displacement results.
    ENVISAT images were provided by ESA and the work was conducted in the framework of the MORFEO project (ASI Contract n. I/045/07/0)

Peer-Reviewed Journal Articles

  • [Smi.JGR2009] A. Smirnov, B. N. Holben, I. Slutsker, D. M. Giles, C. R. Mcclain, T. F. Eck, S. M. Sakerin, A. Macke, P. Croot, G. Zibordi, P. K. Quinn, J. Sciare, S. Kinne, M. Harvey, T. J. Smyth, S. Piketh, T. Zielinski, A. Proshutinsky, J. I. Goes,N. B. Nelson, P. Larouche, V. F. Radionov, P. Goloub, K. Krishna Moorthy, R. Matarrese, (2009) "Maritime Aerosol Network as a component of Aerosol Robotic Network". Journal Of Geophysical Research, VOL. 114, D06204, DOI:10.1029/2008JD011257, 2009. ISSN (printed): 0148-0227. ISSN (electronic): 2156-2202.
    The paper presents the current status of the Maritime Aerosol Network (MAN), which has been developed as a component of the Aerosol Robotic Network (AERONET). MAN deploys Microtops handheld Sun photometers and utilizes the calibration procedure and data processing (Version 2) traceable to AERONET. A web site dedicated to the MAN activity is described. A brief historical perspective is given to aerosol optical depth (AOD) measurements over the oceans. A short summary of the existing data, collected on board ships of opportunity during the NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) Project is presented. Globally averaged oceanic aerosol optical depth (derived from island-based AERONET measurements) at 500 nm is ~0.11 and Angstrom parameter (computed within spectral range 440–870 nm) is calculated to be ~0.6. First results from the cruises contributing to the Maritime Aerosol Network are shown. MAN ship-based aerosol optical depth compares well to simultaneous island and near-coastal AERONET site AOD.
    The authors thank Hal Maring (NASA Headquarters) for his support of AERONET. The authors would like to acknowledge managerial and operational support from W.W. Newcomb, M. Sorokin, A. Scully, A. Tran, D.A. Siegel, K. Knobelspiesse, D. Hamilton, L. Rainville, A. Jayakumar, S. Schick, and D. Menzies (USA); N.T. O’Neill, C. Bourgeault-Brunelle, and M. Palmer (Canada); M. Panchenko, O. Kopelevich, S. Gulev, D. Kabanov, S. Terpugova, V. Polkin, A. Tikhomirov, A. Sinitsyn, Y. Turchinovich, and N. Vlasov (Russia); L. Blarel, J. Nicolas, S. Devidal, L. Martinon, M. Faillot, and C. Petus (France); A. Baker and C. Powell (UK); A. Herber, Y. Zoll, A. Wassmann, and M. Heller (Germany); H. Power, T. Bromley, and R. Martin (New Zealand); J. Piskozub, J. Kowalczyk, and A. Ponczkowska (Poland); D. Williams and B. Kuyper (South Africa); J. Stamnes and S. Iversen (Norway); and K. Niranjan, S. Babu, and S.K. Satheesh (India). We thank the AERONET site managers and the SIMBIOS principal investigators for maintaining the instruments and making collection of these data possible. Jean Sciare would like to thank Institut Polaire Francais (IPEV) and the IPEV-AEROTRACE observatory program for providing technical support and infrastructure. The work of Tymon Zielinski was supported by Polish national grant AERONET59.

  • [Was.PGR2009] J. Wasowski, F. Bovenga, R. Nutricato, D. Conte, A. Refice, M. Graniczny, Z. Kowalski. "Spatial distribution of subsidence in the Wieliczka Salt Mine area as detected through satellite interferometry". In Przeglad Geologiczny, vol. 57, nr 2, 2009, pages 164-172. ISSN-0033-2151.
    The paper presents the use of the Persistent Scatterers Interferometry (PSI) Synthetic Aperture Radar (SAR) data to determine magnitude of subsidence in area of the town ofWieliczka. The town is home to a unique salt mine, over 700 years old, one of the best known tourist attractions in Poland. Each year the mine is visited by about 1 million tourists from all over the world and in 1978 UNESCO placed it on its first International List of theWorld Cultural and Natural Heritage. There is direct evidence that the mining has been influencing stability of ground and buildings in the town, which is located above the mine. The application of the PSI SPINUA technique made it possible to identify large number of radar targets (with density exceeding 100 PS/km2), suitable for monitoring ground motion in the Wieliczka area. The results show continuous subsidence with average annual movements ranging from a few millimeter per year to 24 mm/yr in the period 1992–2000. The detected subsiding zone very well corresponds to the extent of the underground salt mine. There are also indications of possible connections between the mine-induced subsidence and the presence of the old large landslides occurring on the north-facing slopes south of the Wieliczka Salt Mine.
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International Conference Proceedings

  • [Nit.IGARSS2009] Nitti, D.O., Nutricato, R., Bovenga F., Rana F., Conte, D., Guerriero, L. and Milillo, G., “Quantitative Analysis of Stripmap And Spotlight SAR Interferometry with CosmoSkyMed constellation.”. In Proceedings of the IEEE International Geoscience and Remote Sensing Symposium. July 13-17, 2009. Cape Town, South Africa. DOI: 10.1109/IGARSS.2009.5418249. E-ISBN: 978-1-4244-3395-7. Print ISBN: 978-1-4244-3394-0. ISSN: 2153-6996. eISSN: 2153-7003. Scopus: 2-s2.0-77951142859. WOS:000281054100298
    This work is focused on the phase validation of interferograms obtained by combining COSMO-SkyMed SAR images acquired by a single satellite (temporal baseline coincident with the orbital repeat cycle) or even by two satellites of the SAR constellation in equi-phased configuration on the orbital plane (temporal baseline: 8 days), thus minimizing the temporal decorrelation. Both qualitative and quantitative analyses have been therefore carried out for HI (HIMAGE: stripmap, single polarization) and S2 (enhanced spotlight) imaging modes, in order to proof whether or not COSMO-SkyMed constellation is well suited for SAR interferometry.
    Planimetry and heights over Railway Yard "S. Lorenzo" in Rome provided by RFI spa – Dir. Comp. Infr. Roma. All CSK images for the two italian test sites provided by ASI under the ASI - INNOVA contract n. I/038/07/0 and I AA. High precision laser scanning Digital Height Model over Langnau provided by Amt für Geoinformation, Bau-, Verkehrs und Energiedirektion des Kantons Bern. TerraSAR data ((c) Infoterra) are provided by DLR under a Scientific Use License for the proposal MTH0397.

  • [Nit.SPIE2009] D. O. Nitti, R. Nutricato, F. Bovenga, A. Refice, M.T. Chiaradia and L. Guerriero, “TerraSAR-X InSAR multi-pass analysis on Venice (Italy)”. In Proceedings of SPIE Remote Sensing, 31 August-3 September 2009, Berlin, Germany. DOI: 10.1117/12.832047. ISBN: 9780819477828. ISSN 0277-786X. Scopus: 2-s2.0-70350433000.
    The TerraSAR-X mission, launched in 2007, carries a new X-band Synthetic Aperture Radar (SAR) sensor optimally suited for SAR interferometry (InSAR), thus allowing very promising application of InSAR techniques for the risk assessment on areas with hydrogeological instability and especially for multi-temporal analysis, such as Persistent Scatterer Interferometry (PSI) techniques, originally developed at Politecnico di Milano. The SPINUA (Stable Point INterferometry over Unurbanised Areas) technique is a PSI processing methodology which has originally been developed with the aim of detection and monitoring of coherent PS targets in non or scarcely-urbanized areas. The main goal of the present work is to describe successful applications of the SPINUA PSI technique in processing X-band data. Venice has been selected as test site since it is in favorable settings for PSI investigations (urban area containing many potential coherent targets such as buildings) and in view of the availability of a long temporal series of TerraSAR-X stripmap acquisitions (27 scenes in all). The Venice Lagoon is affected by land sinking phenomena, whose origins are both natural and man-induced. The subsidence of Venice has been intensively studied for decades by determining land displacements through traditional monitoring techniques (leveling and GPS) and, recently, by processing stacks of ERS/ENVISAT SAR data. The present work is focused on an independent assessment of application of PSI techniques to TerraSAR-X stripmap data for monitoring the stability of the Venice area. Thanks to its orbital repeat cycle of only 11 days, less than a third of ERS/ENVISAT missions, the maximum displacement rate that can be unambiguously detected along the Line-of-Sight (LOS) with TerraSAR-X SAR data through PSI techniques is expected to be about twice the corresponding value of ESA missions, being directly proportional to the sensor wavelength and inversely proportional to the revisit time. When monitoring displacement phenomena which are known to be within the rate limits, the increased repeat cycle of TerraSAR-X offers the opportunity to decimate the stack of TerraSAR-X data, e.g. by doubling the temporal baseline between subsequent acquisitions. This strategy can be adopted for reducing both economic and computational processing costs. In the present work, the displacement rate maps obtained through SPINUA with and without decimation of the number of Single Look Complex (SLC) acquisitions are compared. In particular, it is shown that with high spatial resolution SAR data, reliable displacement maps could be estimated through PSI techniques with a number of SLCs much lower than in .
    TerraSAR-X data (Infoterra) are provided by Infoterra in the frame of the TerraSAR-X General AO ProjectMTH0432 (PI Maria Teresa Chiaradia).

  • [Nit.SPIE2009b] D. O. Nitti, F. Bovenga, R. Nutricato, F. Rana, C. D’Aprile, P. Frattini, G. Crosta, M. T. Chiaradia, G. Ober and L. Candela, “C- and X-band multi-pass InSAR analysis over Alpine areas (ITALY)”. In Proceedings of SPIE Remote Sensing, 31 August-3 September 2009, Berlin, Germany. DOI: 10.1117/12.849210. ISBN: 9780819477828. ISSN 0277-786X. Scopus: 2-s2.0-70350458742
    In the present work we present first results of ground deformation measurements inferred through repeat-pass Synthetic Aperture Radar (SAR) Interferometry (InSAR) in C- and X-band over an Italian Alpine area, in Lombardia region. The activity was carried out in the framework of the MORFEO (MOnitoraggio e Rischio da Frana mediante dati EO) project founded by the Italian Spatial Agency (ASI) and dedicated to landslide risk assessment. A number of areas affected by hydrogeological instabilities have been selected and studied in detail by processing both C- and X-band SAR data through SPINUA, a Persistent Scatterer like algorithm. In particular, two stacks of 30 Ascending ENVISAT SAR images (October 2004 – January 2009) and 32 Descending ENVISAT SAR images (December 2004 – January 2009) have been independently processed to ensures the detection of movements occurring along both west and east facing slopes. Moreover, further deformation measurements have been obtained by processing a set of 12 COSMO-SkyMED ascending HIMAGE interferometric acquisitions (Satellite CSKS1; Beam HI-03; POL: HH; Incidence Angle: 29°) provided by ASI. After a proper tuning of the interferometric algorithmic solutions, even with very high normal baselines, we are able to appreciate the potentials of X-band interferometry. Although the number of COSMO-SkyMED acquisitions is quite limited, spanning a period of only 10 months (August 2008 – June 2009), SPINUA was capable to retrieve preliminary ground displacement patterns that are in good agreement with those previously estimated in . Quite impressive is to realize that, because of the tenfold improved resolution of X-band images, multi-temporal InSAR techniques may be successfully applied for the estimation of the displacement maps with a number of acquisitions much lower than in . InSAR-derived displacements provided on areas of hydrogeological interest are going to be validated in the framework of MORFEO project by the geological partnership thanks to the availability of ground truths. In the present work, we present the results obtained on the towns of Garzeno, Catasco and Germasino which are affected by landslide phenomena. We provide a first validation by comparing the deformation maps derived from ENVISAT data, from COSMO-SkyMED X-band data as well as from ERS and RADARSAT data freely available on the GeoIFFI web-catalogue.
    ENVISAT and COSMO-SkyMED images were provided respectively by ESA and ASI in the framework of the MORFEO project (ASI Contract n. I/045/07/0).

  • [Nit.FRINGE2009] D.O.Nitti, F. Bovenga, F.Rana, R. Nutricato, M. Tragni, M. T. Chiaradia, G. Ober, L. Candela, “On the use of C- and X-band SAR data for studying the ground deformations induced by the April 6th, 2009 Earthquake in Abruzzo”. In Proceedings of the Workshop Fringe 2009 - Advances in the Science and Applications of SAR Interferometry, November 30 - December 4, 2009, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-677. ISBN 978-92-9221-241-4. ISSN 1609-042X.
    In the study both DInSAR and PSI techniques have been used to generate co-seismic and post-seismic deformation patterns for the Mw=6.3 earthquake which the Abruzzo region in Italy on April 6th, 2009. In particular, we used SAR data acquired in (wavelength of 5.6 cm) by the European Space Agency (ESA) ENVISAT satellite, and X-band (wavelength of 3.1 cm) by the Italian Space Agency (ASI) constellation COSMO-SkyMed (CSK) as well as by the German Space Agency (DLR) TerraSAR-X (TSX). Concerning the co-seismic deformation, is has been studied by processing, through standard DInSAR technique, SAR data with different values of wavelength, spatial as well as incident angles. A comparative analysis of interferometric fringe patterns is presented. Due to the low deformation rate involved, the study of post-seismic events requires the use of a multi-temporal InSAR approach. Thanks to the availability of a stacks of ascending CSK acquisitions, ad hoc programmed by ASI on the area stricken by the earthquake, it was possible to infer post-seismic deformation map through SPINUA PSI-like InSAR analysis. A first validation of these results is also presented.
    The ENVISAT satellite images were made freely available by ESA (dataset SAR Italy earthquake April 2009). The processing of COSMO-SkyMED data was carried out in the framework of MORFEO project (ASI Contract n. I/045/07/0).

  • [Nut.FRINGE2009] R. Nutricato, D. O. Nitti, F. Bovenga, F. Rana, C. D’Aprile, P. Frattini, G. Crosta, G. Venuti, M. T. Chiaradia, G. Ober, L. Candela, “MORFEO PROJECT: C- and X-Band SAR interferometric analysis over Alpine regions (Italy)”. In Proceedings of the Workshop Fringe 2009 - Advances in the Science and Applications of SAR Interferometry, November 30 - December 4, 2009, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-677. ISBN 978-92-9221-241-4. ISSN 1609-042X.
    In the present work we present first results of ground deformation measurements inferred through repeat-pass Synthetic Aperture Radar (SAR) Interferometry (In- SAR) in C- and X-band over an Italian Alpine area, in Lombardia region. The activity was carried out in the framework of the MORFEO (MOnitoraggio e Rischio da Frana mediante dati EO) project, founded by the Italian Spatial Agency (ASI) and dedicated to landslide risk assessment. A number of areas affected by hydrogeological instabilities have been selected and studied in detail by processing both C- and X-band SAR data through SPINUA, a Persistent Scatterer like algorithm. InSAR-derived displacements provided on areas of hydrogeological interest are going to be validated in the framework of MORFEO project by the geological partnership thanks to the availability of ground truths. In the present work, we present the results obtained for test around the towns of Garzeno and Bindo which are both affected by landslide phenomena. For the Garzeno case study we provide also a comparison between the deformation maps derived from ENVISAT and the preliminary results obtained with a limited number of COSMO-SkyMED images, as well as with ERS and RADARSAT PS maps freely available on the GeoIFFIweb-catalogue.
    ENVISAT and COSMO-SkyMED images were provided respectively by ESA and ASI in the framework of the MORFEO project (ASI Contract n. I/045/07/0).

  • [Nit.FRINGE2009b] D. O. Nitti, L. De Vitis, F. Bovenga, R. Nutricato, A. Refice , J. Wasowski, “Multi-temporal L-band SAR interferometry confirms C- band spatial patterns of subsidence in the ancient Wieliczka salt mine (UNESCO heritage site, Poland).”. In Proceedings of the Workshop Fringe 2009 - Advances in the Science and Applications of SAR Interferometry, November 30 - December 4, 2009, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-677. ISBN 978-92-9221-241-4. ISSN 1609-042X.
    This work presents first results of interferometric processing of ALOS PALSAR Single Look Complex SAR images (Fine Beam Mode), concerning ground deformations in the Wieliczka Salt Mine area, a few km from Cracow, Poland. It follows a recent Persistent Scatterers SAR Interferometry (PSI) analysis on this area, obtained by processing several tens of ERS satellite images covering the period 1992-2000. ERS results revealed the presence of a few kilometres long, slowly subsiding zone corresponding very well to the extent of the underground salt mine. The present work aims to extend the analysis by exploiting ALOS-PALSAR data especially for the rural areas, which neighbour the salt mine but lack PS in , relying on the lower sensitivity to temporal decorrelation of L-band w.r.t. radar data. This work shows and compares ERS and PALSAR (Fine Beam) ground displacement patterns detected over the Wieliczka Salt Mine area through the application of multi-temporal interferometric techniques.
    ERS and PALSAR satellite images were provided by ESA under the ALOS ADEN AO 3595 project.

  • [Cza.FRINGE2009] M. Czarnogórska, M. Graniczny, S. Uscinowicz, R. Nutricato, S. Triggiani, D. O. Nitti, F. Bovenga, J. Wasowski, “PSI analysis of ground deformations along the South-Western coast of the Gulf of Gdansk (Poland).”. In Proceedings of the Workshop Fringe 2009 - Advances in the Science and Applications of SAR Interferometry, November 30 - December 4, 2009, ESA/ESRIN, Frascati, Italy. Vol. ESA SP-677. ISBN 978-92-9221-241-4. ISSN 1609-042X.
    We use over 40 descending ERS-1/2 SLC (Frame = 2511 , Track = 36) images from the period 1995 – 2001 and the SPINUA (Stable Point Interferometry over Unurbanised Areas) Persistent Scatterers Interferometry (PSI) processing technique to study Earth surface deformations along the SW coast of the Gulf of Gdansk, along the SE part of the Baltic Sea. The area of interest (AOI) includes few cities and several towns, villages and harbours. The low lying coastal areas of the SW part of the Gulf of Gdansk are at risk of floods and marine erosion. It is expected that this problem can be exacerbated by the ongoing sea level rise and possibly by crustal movements (subsidence) reported in the literature. The PSI results, however, did not reveal the presence of a regional scale, spatially consistent pattern of displacements. It is likely that any crustal deformations in the AOI simply do not exceed +-2 mm/year, which is the velocity threshold we assumed to distinguish between moving and non-moving radar targets. Nevertheless, significant downward displacements, amounting to several mm/year, are locally present in the coastal zone east of Gdansk that belongs to the Vistula river delta-alluvial plain system, as well as in the inland area west of the cities of Gdansk and Sopot. It is apparent that in all these cases the movements reflect mainly differential settlements of buildings and engineering infrastructure, which have recently been built in the areas including clay-rich, compressible sediments. Indeed, one of the highest subsidence rates (- 12 mm/year) was observed in the Gdansk petroleum refinery constructed on alluvial sediments. Thus the anthropogenic loading and consolidation of the recent deposits can locally be an important factor causing ground settlements. Importantly, for the most part the urban areas of the main cities (Gdansk, Gdynia and Sopot) result to be stable
    ERS SAR data were provided by ESA through CAT-1 project n. 4416.

National Conference Proceedings

  • [Nit.ASITA2009] D. O. Nitti, F. Rana, F. Bovenga, R. Nutricato, M. Tragni, M. T. Chiaradia, G. Ober, L. Candela, “Analisi del sisma del 6 Aprile 2009 in Abruzzo con tecniche di Interferometria SAR differenziale”. Atti 13a Conferenza Nazionale ASITA, 1 – 4 dic. 2009, Fiera del Levante Bari, Italia. ISBN: 978-88-903132-2-6.
    Synthetic Aperture Radar (SAR) sensors can provide useful support to the analysis and managing of the natural risks. In particular, SAR Interferometry (InSAR), thanks to its large-scale view area coverage of the deformation field, provides useful measurements for damage assessment of seismic events and fault modelling. The present study is aimed to the application of InSAR techniques for obtaining the co-seismic deformation pattern and inferring the fault model parameters for the Mw=6.3 earthquake which struck the Abruzzo region in Italy on April 6th, 2009. In particular, we used SAR data acquired in (wavelength of 5.6 cm) by the European Space Agency (ESA) ENVISAT satellite, and X-band (wavelength of 3.1 cm) by the German Space Agency (DLR) TerraSAR-X as well as by the Italian Space Agency (ASI) constellation COSMO-SkyMed. Through the SPINUA processing chain, the co-seismic differential interferograms were generated which record the deformation induced by the seismic event. In the present work we present a comparative analysis of interferometric fringe patterns obtained with different values of wavelength, spatial resolution as well as incident angles.
    Gli autori ringraziano l’Agenzia Spaziale Europea per aver messo a disposizione il dataset SAR Italy earthquake April 2009. Le immagini COSMO-SkyMED sono state elaborate nell’ambito del progetto MORFEO (contratto ASI n. I/045/07/0)

  • [Agl.ASITA2009] F. Agliardi, F. Bovenga, L. Candela, M. T. Chiaradia, G.B. Crosta, C. D’Aprile, G. Fornaro, P. Frattini, M. Gilardoni, F. Guzzetti, R. Lanari, D. O. Nitti, R. Nutricato, G. Ober, F. Rana, G. Venuti, G. Zeni, “Attività di elaborazione di dati EO SAR su aree in frana nell’ambito del progetto ASI MORFEO”. Atti 13a Conferenza Nazionale ASITA, 1 – 4 dicembre 2009, Fiera del Levante Bari, Italia. ISBN: 978-88-903132-2-6.
    In the framework of MORFEO project, financed by the Italian Space Agency (ASI), a study is currently under way to estimate and validate monitoring technologies of deformations with SAR data, to the implementation of a pre-operational service supporting the Civil Protection Department in landslide risk monitoring. The study on ground deformations is performed in MORFEO by applying two different technologies: SBAS developed by CNR-IREA in Naples and SPINUA developed by Politecnico of Bari. These technologies work with SAR data in and the use of X-band data acquired by COSMO/SKY-MED is under trial. In particular the present report describes the generation and validation activities of EO SAR products (Synthetic Aperture Radar) obtained in landslide areas in Lombardia and Umbria by using ascending and descending passages of ENVISAT satellite. The results obtained in Umbria highlight the presence of deformation phenomena in the area corresponding to the landslide region in Ivancich (Assisi). A general accordance between GPS and SAR sets results by the comparison. In Lombardia GPS deformation time sets have been estimated for SAR data validation. This has highlighted the potential and limits of SAR interferometric techniques for landslide monitoring in an alpine context. Moreover, a first multi-temporal interferometric analysis in X-band has been carried out through the SPINUA algorithm. Preliminary results over the area of GARZENO (COMO) show that even with a limited number of COSMO/SkyMED images, there is a good agreement with linear displacement rate maps estimated in . An accurate investigation shall be feasible as soon as a consistent number of COSMO/SkyMED acquisitions is available (not less than 25-30).
    This work was supported by ASI, under Contract No. I/045/07/0 “MOnitoraggio del Rishio da Frana mediante dati EO (MORFEO)”.

  • [Abb.ASITA2009] C. Abbattista, R. Nutricato, D. O. Nitti, G. Ober, L. Candela, “Utilizzo congiunto di tecniche e dati SAR con dati in situ nel progetto ASI MORFEO (MOnitoraggio e Rischio da Frana mediante dati EO)”. Atti 13a Conferenza Nazionale ASITA, 1 – 4 dicembre 2009, Fiera del Levante Bari, Italia. ISBN: 978-88-903132-2-6.
    The three year MORFEO pilot project, commissioned by the Italian Space Agency (ASI), implements a Decision Support System for the Civil Protection about the Landslides Risk. The system is based on the use of multi-mission Earth Observation data combined with traditional in situ data and technologies. The project provides the Italian Civil Protection Department with some tools allowing the landslides identification and mapping, a better spatial and temporal forecast of the landslides and the monitoring of landslides movements at local, province or regional scale. This paper describes the MORFEO SAR sub system, whose aim is to generate products for the civil protection thanks to the synergic use of GPS, optic EO and SAR (Synthetic Aperture Radar ) EO data, by the exploitation of new interferometric techniques. The subsystem receives as inputs C, L and X-band SAR data and by using the SPINUA processor produces warping maps as collections of Persistent Scatterers (PS) points. Combining those maps with Optic EO data and GPS data, is possible to generate high level products like PS coverage maps, contextual maps, statistical products and correlation maps.
    This work was supported by ASI, under Contract No. I/045/07/0 “MOnitoraggio del Rishio da Frana mediante dati EO (MORFEO)”.

Peer-Reviewed Journal Articles

  • [DeA.NuovoSag2008] A. De Angelis, N. Giglietto, L. Guerriero, E. Menichetti, P. Spinelli, S. Stramaglia, "Domenico Pacini, un pioniere dimenticato dello studio dei raggi cosmici". Il Nuovo Saggiatore Vol. 24, No 3-4, pag. 70-74 (2008). ISSN 0393-4578 (print). E-ISSN 1827-6148.
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    Si ringrazia l'Università di Bari per l'aiuto fornito nel ritrovare materiale e documenti relativi a D. Pacini, il Dipartimento Interateneo di Fisica di Bari per la collaborazione nell'organizzare la giornata commemorativa tenutasi a Bari il 17 aprile 2007, e quanti hanno collaborato a questa in particolare F. Guerra e Robotti, i quali hanno contribuito nella ricerca di documenti presso completando il quadro “sociologico” del contesto in cui operò Pacini e quanti hanno partecipato a questo evento.

International Conference Proceedings

  • [Was.ISL2008] Wasowsky, J., Bovenga, F., Nutricato, R., Nitti, D.O., Refice, A. and Casarano, D., “Landslide-prone towns in Daunia (Italy): PS interferometry-based investigation”. In: Landslides And Engineered Slopes: From The Past To The Future. Proceedings of the 10th International Symposium On Landslides And Engineered Slopes. June 30 – July 4, 2008. Xi'an, China. vol. 1, p. 513-518, Chen, Z; Zhang, JM; Li, ZK; Wu, FQ; Ho, K, Print ISBN: 978-0-415-41196-7. eBook ISBN: 978-0-203-88528-4. DOI: 10.1201/9780203885284-c58. WOS:000266239200058
    Persistent Scatterers Interferometry (PSI) and satellite radar imagery can be used to detect very slow displacements (mm-cm per year) of targets (PS) exhibiting coherent radar backscattering properties (mainly man-made structures). Here we present results of the PSI application to the Daunia Apennines, which include many hilltop towns affected by landslides. Examples from the towns Casalnuovo Monterotaro and Pietramontecorvino are used to illustrate that the interpretation of PS data on urbanised slopes can be difficult, because their movements may arise from a variety of processes: i) volumetric strains within soils, ii) natural or anthropogenic subsidence or uplift, iii) settlement of engineering structures, iv) deterioration of man-made structures, v) extremely slow slope deformations that may or may not lead to failure. Where true landslide movements are detected, they likely regard long-term post-failure displacements involving clay-rich materials.
    This work was supported in part by the European Community (Contract No. EVGI 2001-00055—Project LEWIS). Images were provided by ESA under the CAT-1 project 2653.

  • [Nit.SPIE2008] Nitti D.O., Hanssen R.F., Refice A., Bovenga F., Milillo G. and Nutricato R., “Evaluation of DEM-assisted SAR coregistration”. In Proceedings of SPIE Remote Sensing, 15–18 Sept. 2008. Cardiff, Wales, United Kingdom (2008). DOI: 10.1117/12.802767. ISBN: 9780819473400. ISSN 0277-786X. Scopus: 2-s2.0-57649112728
    Image alignment is without doubt the most crucial step in SAR Interferometry. Interferogram formation requires images to be coregistered with an accuracy of better than 1/8 pixel to avoid significant loss of phase coherence. Conventional interferometric precise coregistration methods for full-resolution SAR data (Single-Look Complex imagery, or SLC) are based on the cross-correlation of the SLC data, either in the original complex form or as squared amplitudes. Offset vectors in slant range and azimuth directions are computed on a large number of windows, according to the estimated correlation peaks. Then, a two-dimensional polynomial of a certain degree is usually chosen as warp function and the polynomial parameters are estimated through LMS fit from the shifts measured on the image windows. In case of rough topography and long baselines, the polynomial approximation for the warp function becomes inaccurate, leading to local misregistrations. Moreover, these effects increase with the spatial resolution and then with the sampling frequency of the sensor, as first results on TerraSAR-X interferometry confirm. An improved, DEM-assisted image coregistration procedure can be adopted for providing higher-order prediction of the offset vectors. Instead of estimating the shifts on a limited number of patches and using a polynomial approximation for the transformation, this approach computes pixel by pixel the correspondence between master and slave by using the orbital data and a reference DEM. This study assesses the performance of this approach with respect to the standard procedure. In particular, both analytical relationships and simulations will evaluate the impact of the finite vertical accuracy of the DEM on the final coregistration precision for different radar postings and relative positions of satellites. The two approaches are compared by processing real data at different carrier frequencies and using the interferometric coherence as quality figure.
    TerraSAR data ((c) Infoterra) were kindly provided by Infoterra and acquired (Sales Order Number 5832) in the framework of the SAMAAV project (Study And Monitoring of Active African Volcanoes) coordinated by Royal Museum for Central Africa in Belgium and National Museum of Natural History of Luxembourg (contacts: francois.kervyn@africamuseum.be and nicolas.doreye@ecgs.lu). PALSAR images provided by European Space Agency (ESA) under the ALOS ADEN AO 3595 project. ERS data provided by ESA under the CAT-1 project n.2653. The authors thank Antonio Valentino of the Consortium Innova (Italy) for the fruitful collaboration.

  • [Nit.ALOSPI2008] Nitti, D.O., Bovenga, F., Refice, A., Wasowski, J., Conte, D., Nutricato, R., “L- and SAR Interferometry analysis of the Wieliczka salt mine area (UNESCO heritage site, Poland)”. In Proceedings of the 2008 Joint PI Symposium of the ALOS Data Nodes. 3 – 7 Nov., 2008. Rhodes, Greece (2008). Vol.: ESA-SP 664. ISBN: 978-92-9221-228-5. ISSN 1609-042X. Scopus: 2-s2.0-77955176893
    This work presents first results of interferometric processing of ALOS PALSAR Single Look Complex SAR images (Stripmap Single Polarization Mode), concerning ground deformations in the Wieliczka Salt Mine area, a few km from Cracow, Poland. It follows a recent Persistent Scatterers SAR Interferometry (PSI) analysis on this area, obtained by processing several tens of ERS satellite images covering the period 1992-2000. The results revealed the presence of a few kilometres long, slowly subsiding zone corresponding very well to the extent of the underground salt mine. The present work aims to extend the analysis by exploiting ALOS-PALSAR data especially for the neighbouring rural areas, relying on the lower sensitivity to temporal decorrelation of L-band w.r.t. radar data. Use of L band data is of interest because it could allow detecting faster ground movements related to sudden subsidence events that have occasionally occurred in the recent past. One such event, reported in the 1990’s, caused ground displacements locally exceeding 3 m. Furthermore, with L-band SAR data some useful information can be obtained for the rural areas, which neighbour the salt mine but lack PS. We present results obtained from Fine Beam, HH Single Polarization Mode (FBS), 34.3° Off-Nadir look-angle SAR images. The night acquisition time of FBS PALSAR images mitigates the atmospheric phase screen in each interferogram. No clear evidence of displacements is found on ALOS interferograms spanning about 1 year. The relatively high coherence shown by the interferograms allows easier unwrapping of the differential interferometric phase, aiding further statistical investigations on the spatial properties of the atmospheric signal. We also present considerations concerning some processing aspects of ALOS data, as well as a preliminary comparison between the L-band and differential interferometric phase behaviour.
    PALSAR satellite images were provided by ESA under the ALOS ADEN AO 3595 project.

  • [Mat.IGARSS2008] R. Matarrese, A. Morea, K. Tijani, V. De Pasquale, M.T. Chiaradia, G. Pasquariello “A Specialized Support Vector Machine Coastal Water Chlorophyll Retrieval From Water Leaving Reflectances”. Proceedings of IGARSS 2008, Poster Session, July 6-11, 2008. Boston, Massachussetts, U.S.A. DOI: 10.1109/IGARSS.2008.4779871. E-ISBN: 978-1-4244-2808-3. Print ISBN: 978-1-4244-2807-6.
    Ocean colors observed by satellite are the measure of the water leaving reflectance of the investigated area, and vary according to the concentration of water’s constituents. The relationship between satellite-derived ocean colors and chlorophyll a concentrations has been studied for several decades [1-3], and several model-based estimation algorithms have been proposed. Analytical models take account of all parameters relating water leaving reflectance with chlorophyll concentration [4]. In empirical approaches remote sensed data is related to the chlorophyll concentration by interpolation techniques applied to a set of training samples. Several neural networks based algorithms have been proposed for the empirical approach [5-10]. In [11] a performance evaluation between several empirical approaches in inversion problems, shown that the use of the support vector machine (SVM) can improve the state of the art neural network solution. In this paper we propose a SVM specialized on Apulian coastal zones showing very encouraging results.
    This work has been supported by MIUR (Ministero dell’Università e della Ricerca), within the framework of IMCA project (Integrated Monitoring of Coastal Areas).

  • [Mat.IGARSS2008b] R. Matarrese, M. Acquaro, A. Morea, K.Tijani, M.T.Chiaradia “Applications Of Remote Sensing Techniques For Mapping Posidonia Oceanica Meadows”. Proceedings of IGARSS 2008, Poster Session, July 6-11, 2008. Boston, Massachussetts, U.S.A. DOI: 10.1109/IGARSS.2008.4779870. E-ISBN: 978-1-4244-2808-3. Print ISBN: 978-1-4244-2807-6.
    Posidonia Oceanica is a marine phanerogam characterizing an ultimate succession stage (climax) on sandy bottoms in the Mediterranean Sea. In particular, Posidonia Oceanica ecosystems are an important element in improving the water quality of coastal waters [1], [2]. Producing thematic maps of seagrass communities from remote sensing data is a multistep process. First, a preprocessing phase to correct satellite images. The second step is the classification phase. Subsequently the postclassification phase have to improve the accuracy of the results. In this study, Posidonia Oceanica meadows maps of Taranto Gulf, Ionian Sea, in 2001, 2002, and 2004, are produced from Ikonos, ETM+ and ASTER images. A comparison with ground truth measurements in the Ionian Sea shows the advantages and the limits of each approach.
    This work has been supported by MIUR (Ministero dell’Università e della Ricerca), within the framework of IMCA project (Integrated Monitoring of Coastal Areas).

National Conference Proceedings

  • [Chi.ADB2008] Chiaradia M.T., Francioso R., Matarrese R., Petrillo A. F., Ranieri G., Urrutia C. (2008) – Estrazione Semi-Automatica Della Linea Di Costa Da Immagini Satellitari Ad Alta Risoluzione: Valutazione Ed Applicabilità. Collana Editoriale Di Studi E Ricerche Dell’autorità Di Bacino Della Basilicata, N. 9.
    La conoscenza della posizione della linea di riva è uno degli elementi fondamentali nella pianificazione della fascia costiera. È noto che essa subisce spostamenti di carattere stagionale, ma che mediamente tende ad una situazione di equilibrio, a meno di modificazioni del trasporto solido costiero determinato da azioni antropiche nei bacini idrografici in cui è inserita l’unità fisiografica del litorale in esame o dalla realizzazione di opere a mare. Da qui la necessità di supportare la pianificazione della fascia costiera con il monitoraggio della linea di riva con rilievi almeno semestrali al fine di correggere le variabilità stagionali o le singolarità indotte da mareggiate intense. La linea di riva normalmente si ricava da rilievi tradizionali in situ, tuttavia non mancano esempi di estrazione da cartografia ortografica e da immagini satellitari. Uno degli obbiettivi del progetto IMCA finanziato con fondi PON, è stato quello di attivare una procedura semi-automatica per l’estrazione della posizione della linea di riva da immagini satellitari ad alta risoluzione. Nel presente lavoro è illustrata la tecnica utilizzata per questa procedura, i risultati ottenuti in un caso reale di applicazione e la valutazione della loro affidabilità.
    This work has been supported by MIUR (Ministero dell’Università e della Ricerca), within the framework of IMCA project (Integrated Monitoring of Coastal Areas).

Conference Abstracts

  • [Dou.CeTeM2008] Doubell, M., Fasano, L., Ferri, V., Lorè, V.A., Milillo, G., Nitti D.O., Nutricato, R., Conte, D., Bovenga, F., Valentino, A., “COSMO SKYMED qualitative analysis and examples using “GSDVIEW” open source graphic tool and interferometric measurements”. XIV Annual Meeting CeTeM / V Workshop AIT / XIV MECSA Day on Microwave Engineering. Microwave Remote Sensing: systems, propagation, algorithms: from technologies to applications. 23-24 Oct., 2008. Rome, Italy (2008).
    The COSMO-SkyMed constellation will acquire data from its four SAR satellites in several image modes, and will generate focused data products. Presently, two satellites are in orbit. The constellation will be completed by 2009. In this paper we detail the analysis and experimentation carried out with the first COSMO-SkyMed real SAR data. A qualitative analysis and in part a quantitative analysis have been carried out with the support of the correspondent optical images. The steps used have been to: 1. Individualize the targets and the characteristics of the SAR data; 2. Verify the characteristics of the data, of the satellite configuration and of the SAR; 3. Interpret the data and the connected phenomena; 4. Carry out both qualitative and quantitative analysis on InSAR phase with preliminary height measurements. The operational instrument with which the COSMO-SkyMed images have been elaborated has been the "GSDView" Open Source Tool, currently under development by INNOVA Consorzio per l'Informatica la Telematica under an ASI (Italian Space Agency) contract. Various contexts have been analyzed within the SAR images, with specific attention to human interest areas, such as: metropolitan areas, ports and coasts and agricultural areas. The data set used for the analysis has been predominantly from SCS (Single-look Complex Slant), DGM (Detected Ground Multilook), GEC (Geocoded Ellipsoid Corrected) and GTC (Geocoded Terrain Corrected) products acquired by the COSMO-SkyMed satellites SAR1 and/or SAR2 in StripMap and Spotlight acquisition modes. The completed analysis shows the great potential of the sensor. The COSMO-SkyMed data regards the possible use in Earth Observation (EO) applications such as Change Detection (CD), Moving Target Detection (MTD), and Interferometry. The interferometric analysis first verified the impact of an improved tool for coregistering SAR images that uses DEM and orbital information instead of polynomial models. This approach results in better performance for high resolution CSK images especially in areas with rough topography. Once the InSAR processing chain was properly updated, interferograms were computed by using both CSK-1 and CSK-2 data and first height retrieval experiments were carried out. The higher resolution of CSK images and the short revisitation rate of the full constellation will ensure a more detailed InSAR phase allowing new potential applications (urban applications, precise DEM, etc.). The applications studied are of significant importance in both Military and Civil spheres because they consent target detection with geometric and physical characteristics. The stability and high resolution characteristics of the sensor together with the fast revisit rate foreseen for the COSMO-SkyMed system will allow to define new high level product categories and make possible new innovative applications for the EO field.
    Attività realizzata da GAP nell’ambito del Contratto ASI - INNOVA n I/038/07/0 e I AA

  • [DeP.IGARSS2008] V. De Pasquale, R. Matarrese, G. Pasquariello, M.T. Chiaradia, "Validation of chlorophyll concentration algorithms in Apulian coastal areas". Abstracts of IGARSS 2008, poster session, July 6-11, 2008. Boston, Massachussetts, U.S.A. http://www.igarss08.org/Abstracts/pdfs/3694.pdf
    Monitoring and managing small coastal ecosystems require a considerable understanding of temporal dynamics of biophysical factors describing coastal water systems. For this reason, daily observation from space could be a very efficient tool. For this purpose, high resolution, multispectral satellite data have been successfully applied in the detection of chemical, biological and physical processes happening in coastal waters. However, monitoring coastal waters using the existing satellite instruments, is a challenging task which requires very sophisticate procedures. We know that in open oceans, case I waters, phytoplankton is the principal agent responsible for the optical properties of waters. Instead, the optical properties of shallow and coastal waters, case II waters, are influenced not only by phytoplankton, but also by other substances, generally classified as suspended inorganic particles and yellow substance [1]. In the framework of IMCA project (Integrated Monitoring of Coastal Area) an important set of in situ measurements has been carried out. Beside lab-measurements of water quality parameters and their inherent optical properties, a set of radiometric measurements have been performed. This measurements consist of downwelling irradiance above water, and in water profiles of downwelling irradiance, upwelling radiance, fluorimetric chlorophyll-a concentration, temperature and other ancillary quantities. These measurements are performed using the Satlantic Profile II, a free fall profiler with OCR- 507 I and OCR-507 R radiometers connected. The areas of interest are located in the south-east of Italy in the region of Apulia. In this region, three sites have been selected: 1) Taranto seas on the Ionian Sea. This site is characterized by a strong human activity for the presence of important industrial settlements with an high traffic commercial port and a base of Italian Military Marine; 2) Margherita di Savoia and estuarine of Ofanto river on the Adriatic Sea. The waters of this area are very turbid due to the presence of the river and for some industrial settlements near the small town; 3) Tremiti islands on the Adriatic sea, an important marine protected area characterized by clear water conditions. In these areas a total of 25 stations located within 3 km from the shore have been selected, and the measurements have been performed about twice per month, according on the cloud free satellite overpasses from Spring 2006 to Spring 2008. The aim of this paper is the validation of some bio-optical algorithms for the retrieval of chlorophyll-a concentration. The remote sensing reflectances derived from in situ measurements have been used as input for the algorithms, and the resulting chlorophyll concentrations have been compared to the one measured by the fluorimeter and with the one derived by the water samples using the HPLC technique. Three algorithms have been selected. The first one is a simple empirical algorithm[2]. It has been selected to test the hypothesis that the Tremiti site could be considered as case I area. The other two algorithms are semi-analytical ones: the GSM algorithm [3] and Carder algorithm[4].
    This work has been supported by MIUR (Ministero dell’Università e della Ricerca), within the framework of IMCA project (Integrated Monitoring of Coastal Areas).

Other poster/slideshow presentations

  • [Bov.Ka2008] Bovenga F., Conte, D., Nitti, D.O., Nutricato, R., Milillo, G. and Valentino, A., “Preliminary Analysis of Cosmo-SkyMed Interferometric Phase”. 14th Ka and Broadband Communications, Navigation and Earth Observation Conference. September 24-26, 2008. Matera, Italy (2008).
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  • [Gue.FestInnov2008] L. Guerriero, M.T. Chiaradia, R. Matarrese, R. Nutricato, F. Bovenga, A. Morea, D. Conte, F. Intini, K. Tijani, and D.O. Nitti. Nuove potenzialità del telerilevamento satellitare per il monitoraggio ambientale: attività dello spin-off Geophysical Applications Processing - GAP s.r.l. del Politecnico di Bari presso il Dipartimento Interateneo di Fisica. Festival dell'innovazione 2008, Giornata sulla Ricerca nel Settore Aerospaziale in Puglia, Bari, Italy, Dec 4, 2008.
    Presso il Dipartimento Interateneo di Fisica dell’Università e del Politecnico di Bari, il Gruppo di Remote Sensing opera da più di dieci anni nel campo dell’elaborazione dei segnali e delle immagini ed ha sviluppato metodologie, modelli numerici ed algoritmi per numerose applicazioni innovative del telerilevamento satellitare, dal monitoraggio del territorio allo studio dell’ambiente e dell’evoluzione climatica. Due sono le aree di specializzazione che caratterizzano le competenze del gruppo e che hanno permesso di creare lo spin-off Geophysical Applications Processing - GAP s.r.l. del Politecnico di Bari. La prima riguarda l’interferometria differenziale con immagini radar ad apertura sintetica (SAR) e le tecniche interferometriche multitemporali con gli scatteratori persistenti in aree di scarsa urbanizzazione. Con questa tecnica è possibile individuare movimenti millimetrici e velocità di spostamento dell’ordine di alcuni millimetri l’anno per strutture antropiche o natuali. Le procedure sviluppate, per le quali è stata avviata la procedura di brevettazione, sono state applicate per l’individuazione di instabilità dei pendii e spostamenti premonitori di pericolo di frana, instabilità di edifici in aree urbane, instabilità di manufatti, quali dighe, viadotti, ponti, etc. Nuove interessanti potenzialità di questa metodologia sono oggi offerte dalla recentissima costellazione di satelliti COSMO-SkyMed dell’Agenzia Spaziale Italiana. La seconda area di specializzazione riguarda il monitoraggio dello stato di salute delle acque costiere e la densità di aerosol nell’atmosfera, utilizzando, mediante sofisticate procedure di filtraggio e di inversione numerica, dati ad alta frequenza temporale e a bassa risoluzione spaziale, forniti dai numerosi sensori multispettrali delle piattaforme spaziali realizzate dall’ESA e dalla NASA per studi di oceanografia. Diversi progetti finanziati dall’Agenzia Spaziale Italiana, dall’Unione Europea, dall’Agenzia Spaziale Europea, dal MIUR, dalla Regione Puglia, quali MORFEO (ASI), IMCA (MIUR), LEWIS (VII Programma Quadro), WETSYS (Interreg Italia-Albania), nonché la recente convenzione tra GAP s.r.l. e la Regione Puglia in materia di incendi boschivi, si sono avvalsi dell’apporto scientifico e dei risultati della ricerca del Dipartimento Interateneo di Fisica. I risultati più maturi sono ora divenuti applicazioni commerciali dello spin-off GAP s.r.l. Verrà presentata una panoramica delle metodologie sviluppate dal Gruppo di Telerilevamento di Bari e da GAP s.r.l., nell’ambito di recenti progetti nazionali ed internazionali.
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  • [Lat.ICT2008] A. Lattanzi, F. Bettarelli, S. Cecchi, R. Nutricato, "hArtes Toolchain: algorithm space exploration and translation toolbox", poster presented at ICT Conference - Lyon (France), 25-27 November 2008.
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    hArtes project (IST-035143) supported by the Sixth Framework Programme of the European Community under the thematic area Embedded Systems.

International Conference Proceedings

  • [Bov.VECIMS2007] F. Bovenga, E. Miali, R. Nutricato, M. T. Chiaradia, “GIS-based system for Landslide Early Warning index measurement”, Proceedings of IEEE International Conference on Virtual Environments, Human-Computer Interfaces, and Measurement Systems (VECIMS 2007), 25-27 June 2007, Ostuni (Italy). DOI: 10.1109/VECIMS.2007.4373932. E-ISBN: 978-1-4244-0820-7. Print ISBN: 978-1-4244-0820-7
    Landslides are one of the most serious natural and man induced hazards. The paper presents an innovative system dedicated to the measurement of landslide warning index. The system is based on a Geographic Information System (GIS) inference engine which properly combine satellite Earth Observation (EO) measurements and static geophysical parameters. The system has been developed in the framework of a FP5 European project and it is aimed to provide an operative and flexible tool for public and private entities involved in land management, and in particular in mitigation of both landslide hazard and risk. Particular attention will be devoted to the role that the GIS environment plays as optimal measurement environment since it provides flexible interface between human (both high level geophysical experts and low level end users) and data (heterogeneous data in input to the geophysical model, warning maps in output).
    The authors would mention all the partners of LEWIS project and in particular Dr. Janusz Wasowski and Dr. Domenico Casarano from CNR-IRPI, Bari for the work dedicated to define and to validate the geophysical rules and, the staff of SILOGIC for the development of the GIS tool for PS analysis.

  • [Gue.VECIMS2007] A. Guerriero, R. Matarrese, A. Morea, C. Pasquale, F. Ragni, K. Tijani, "GRID Services for SST Measures". , Proceedings of IEEE International Conference on Virtual Environments, Human-Computer Interfaces, and Measurement Systems (VECIMS 2007), 25-27 June 2007, Ostuni (Italy). DOI: 10.1109/VECIMS.2007.4373935. ISBN: 978-1-4244-0820-7
    The effects of the increase in the average temperature of the Earth's near-surface air and oceans in recent decades are dramatically manifest: desertification, glacier retreat, increased intensity and frequency of hurricanes and extreme weather events. Monitoring the ecosystem is currently the only way we have to assist Governments in making sound decisions concerning the reduction of these dramatic effects and the protection of our environment. Satellite remote sensing data, offering the possibility of covering large spatial area with a high temporal frequency, represents the ideal solution to monitoring, but the huge data volume to process, calibrate and validate by in-situ dataset, cannot be operated effectively by traditional database and computational resources. Grid technology, easily providing powerful computational resources and efficient distributed data management, is an excellent solution for remote sensed data processing and management system. In this paper we present a prototype of a Remote Sensed Data processing system on Grid technology that allows, by a graphical interface, data selection and processing to validate SST measure particularly in costal area.
    This work was partly supported by European Regional Development Found (ERDF), “New.Ton” Project (project code A.1.180 - Interreg IIIB Archimed programme). The authors thank very much the reviewers for their constructive and useful comments.

  • [Was.FRINGE2007] J. Wasowski, F. Bovenga, R. Nutricato, D. Conte, A. Refice, Z. Kowalski, M. Graniczny, "Satellite interferometry reveals spatial patterns of subsidence in the ancient Wieliczka Salt Mine (UNESCO Heritage Site, Poland)", Proceedings of FRINGE 2007, ESA-ESRIN, Frascati (RM), Italy, 26-30 Nov. 2007.2. ISBN 9789292912133. ISSN 1609-042X.
    We present the first Persistent Scatterers SAR Interferometry (PSI) data on the subsidence phenomena in the town of Wieliczka. The town is home to a unique salt mine, over 700 years old, one of the best known tourist attractions in Poland. Each year the mine is visited by about 1 million tourists from all over the world and in 1978 UNESCO placed it on its first International List of theWorld Cultural and Natural Heritage. There is evidence that the mining legacy has influenced the ground and building stability in the town, which is sited directly above the mine. The application of the PSI SPINUA technique has led to the identification of numerous radar targets (over 100 PS/km2), suitable for ground motion monitoring in the Wieliczka area. The results show the presence of continuous subsidence with average movements ranging from about 1 to 2 cm/yr in the period 1992-2000. The detected subsiding zone corresponds well to the extent of the underground salt mine. There are also indications of possible linkages between the mine-induced subsidence and the presence of the relatively large landslides occurring on the north slopes facing the Wieliczka area.
    The ERS images were provided by ESA under the ALOS ADEN 3595 project. JW thanks Marek and Karol Kotlinowski for their hospitality and help, A. Lesniak for precipitation data and A. Trzoslo for sharing information on the Wieliczka mine operations.

  • [Vie.EnvSymp2007] M. Viel, G. Ceriola, P. Manunta, R. Matarrese, V. De Pasquale, G. Pasquariello, "MARCOAST Adriatic Service, MERIS Products Validation". Proc. 'Envisat Symposium 2007', Montreux, Switzerland 23-27 April 2007. ESA SP-636, ISBN 92-9291-200-1. ISSN 1609-042X.
    Coastal zones are the most populated and utilized areas of the earth. Assessment and regular monitoring of coastal waters quality are key activities for a sound management of the coastal areas. Chlorophyll-a (Chl-a) is one of the key parameters used for evaluating coastal water quality status. MarCoast is a three year project funded by the European Space Agency (ESA) with the aim of establishing a durable network of marine and coastal information services from remote sensing data, integrated with in-situ measurement, in close cooperation with national and regional authorities. In MarCoast, Chl-a and Water Transparency parameters are both measured with the MERIS instrument onboard ENVISAT. This paper describes the outcomes of validation activities of the MERIS products and algorithms performed for the Adriatic Sea using in situ data. First validation results made on oneyear dataset were promising. However, further analysis should be made to confirm this first year good results and to improve regionalization of the algorithms.
    Work carried out in the framework of MarCoast (Marine and Coastal Environmental Information Services), a 3 years (2005–2008) project fully funded by the European Space Agency (ESA) in the context of the GMES (Global Monitoring for Environment and Security) Service Element Programme.

  • [Was.EnvSymp2007] J. Wasowski, D. Casarano, C. Lamanna, F. Bovenga, D. Conte, R. Nutricato, A. Refice, P. Berardino, M. Manzo, A. Pepe, G. Zeni, R. Lanari, "A Comparative Analysis of DInSAR results achived by the SBAS and SPINUA techniques: the Maratea Valley case study, Italy", Proceedings of ESA-ENVISAT Symposium 2007, 23-26 April, 2007, Montreux, Swiss. ESA SP-636, ISBN 92-9291-200-1. ISSN 1609-042X.
    We compare the results of two independent synthetic aperture radar differential interferometry (DInSAR) ap-proaches to slope instability investigations in the Mara-tea valley (Southern Italy), based on different process-ing methods and software. The area selected for the comparison is well ground truthed and provides suitable examples of movements ranging from mm to cm per year. The DInSAR analyses are based on the Small Baseline Subset (SBAS) and Stable Point INterferome-try over Unurbanised Areas (SPINUA) techniques. Both methods are applied to SAR images acquired by the ERS-1/2 satellites in the period 1992-2000. Despite the differences in the data processing and minor discrepan-cies between the displacement maps, mainly due to dif-ferences in data classification and thresholding, the re-sults obtained from the two techniques are largely com-parable and provide very similar ground surface motion information that leads to a clear distinction between sta-ble and unstable areas and between the zones with dif-ferent velocity of movement.
    The European Space Agency provided the ERS SAR data. The authors also thank the Autorità Interregionale di Bacino della Basilicata for the orthophotos of the Maratea Valley.

  • [Gue.MACMESE2007] A. Guerriero, R. Matarrese, A. Morea, K. Tijani, "A GRID Enabled Look-Up Table for Aerosol Optical Thickness Estimation on Coastal Water". Proceedings of the 9th WSEAS International Conference on Mathematical and Computational Methods in Science and Engineering, pp. 137-141, (MACMESE 07), Trinidad and Tobago, 5-7 November 2007. ISBN: 978-960-6766-12-1
    Coastal area represents one of the more delicate and complex relation between natural environment and human activities. Remote sensing, offering considerable understanding of the temporal dynamics of bio-physical factors at different scale, represents a solution for monitoring the ecosystem. In particular marine phenomena, i.e. Sea Surface Temperature, chlorophyll concentration etc. can be related to the sea color observed from satellites. However standard satellite products, such as chlorophyll concentrations maps calculated from MODIS data, are useful only for oceanic water and cannot be directly extended to coastal water. For coastal water quality evaluation, specific inversion procedures should be used. Some of these procedures are based on look-up table generation that are computational intensive. In this paper a Grid based approach is proposed for LUT generation. This approach, producing accurate estimation of Aerosol Optical Thickness, represents a useful system to give fast and accurate answers without demand large economic investments.
    This work is partially supported by the "New. Ton." Project, co-financed by the ERDF through the INTERREG IIIB ARCHIMED Programme A.1.180 (http://www.newton.interreg.net)

  • [Gue.IWASI2007] A. Guerriero, R. Matarrese, A. Morea, C. Pasquale, F. Ragni, K. Tijani, "A Grid Portal to Improve SST Maps". IWASI 2007, Bari June 26-27, 2007. DOI: 10.1109/IWASI.2007.4420044. E-ISBN: 978-1-4244-1245-7. Print ISBN: 978-1-4244-1245-7.
    New technologies, sensors and techniques increase every day the human capabilities to monitoring the ecosystem and understanding the anthropogenic influence in its evolution. Particularly remote sensing, offering the possibility of covering large spatial area with a high temporal frequency, represents the ideal solution to environmental monitoring, but at the same time it is a challenge for any conventional computational resource due to the algorithms complexity and to the huge data volume to process. EOS satellites with their Moderate Resolution Imaging Spectroradiometers (MODIS) view the entire Earth's surface every days, acquiring data in 36 spectral bands. These data are used to make several products, i.e. Oceans Sea Surface Temperature Maps, essential for understanding a number of oceanographic and atmospheric phenomena. On coastal areas the SST product is unreliable requiring ad hoc processing and calibration. These requirements fit better on High Performance Computing and Grid technologies that can provide powerful computational resources and efficient distributed data management. Several Grid infrastructures have been proposed in literature for Earth observation projects [1-3], however they report excellent performance but a too complex computing environment for non grid expert users. In this paper we present a Grid Portal for Remote Sensing data processing that allows scientists to access resources, execute and monitor data processing on Grid technology using a simple web browser interface. As an example of services that can be offered in this Portal we implement services for producing calibrate costal area SST maps and for combining these with standard product to obtain improved SST maps.
    This work was partly supported by European Regional Development Found (ERDF), “New.Ton” Project (project code A.1.180 - Interreg IIIB Archimed programme). The authors thank very much the reviewers for their constructive and useful comments.

National Conference Proceedings

  • [Mat.Wetland2007] R. Matarrese, M.T. Chiaradia “Applicazioni Del Telerilevamento A Zone Costiere E Umide”. Atti Del Congresso Environmental Features And Sustainable Development Of The Albanian And Apulian Wetlands – Tirana, 23 Novembre 2007, Pp. 107-110, Edizioni Dal Sud. ISBN: 88-7553-061-0.
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  • [Mat.ChimAmb2007] R. Matarrese, V. De Pasquale, S. Rochira, P. Cosma, M. Trotta, M.T. Chiaradia, G. Pasquariello. “Calibrazione di un profilatore per misure fluorimetriche in situ per lo sviluppo di modelli bioottici satellitari". X Congresso Nazionale Di Chimica Dell'ambiente E Dei Beni Culturali, Acaya, Lecce, 11-15 Giugno 2007.
    Le acque costiere rappresentano solo una piccola frazione delle acque naturali del pianeta, ma risultano di fondamentale importanza per il loro ruolo economico, sociale ed ecologico. Il loro monitoraggio assume, dunque, una particolare rilevanza. La misura di parametri fisici, chimici e biologici che fungono da indicatori della qualità delle acque è effettuata tradizionalmente con campagne periodiche di prelievo di campioni a mare. I recenti sviluppi dei sistemi di elaborazione dati di immagini satellitari, hanno mostrato come questa nuova tecnica possa integrarsi a quelle tradizionali, fornendo informazioni sinottiche e a basso costo di alcuni indici dello stato delle acque. Da misure satellitari sono determinabili solo quelle sostanze che interagiscono con la radiazione solare che ha attraversato la superficie marina, ovvero la clorofilla di alghe e cianobatteri, i sedimenti sospesi e la sostanza gialla. Gli algoritmi ad oggi disponibili sono ottimizzati per misure in acque oceaniche (Caso I). Per le aree costiere (Caso II), tuttavia, tali algoritmi possono non essere adeguati ed è quindi necessario svilupparne una versione che sia adatta alle caratteristiche di queste acque, che possono variare drasticamente da zona a zona. Tale sviluppo può essere effettuato solo utilizzando misure chimiche, biochimiche e radiometriche in situ. Il contenuto in clorofilla di un'acqua è direttamente legato alla quantità di microrganismi fotosintetici ivi contenuti. La loro distribuzione in termini di specie e di concentrazione è fortemente dipendente dalle caratteristiche chimico fisiche delle acque, come ad esempio temperatura, pH e soprattutto concentrazione di nutriliti. Questi parametri dipendono dalla zona costiera dalla quale i prelievi sono effettuati e tendono ad essere differenti fra i siti di Taranto, Margherita di Savoia e Isole Tremiti oggetto dell’indagine. Le misure in situ del contenuto in clorofilla parametro su cui si focalizza questo lavoro, sono effettuate tramite misure fluorimetriche. Campioni di acqua prelevati nelle posizioni delle misure, sono successivamente analizzati in laboratorio con cromatografia liquida. Le misure fluorimetriche sono così calibrate con i valori ottenuti in laboratorio e vengono a loro volta utilizzate per calibrare gli algoritmi satellitari. In questo lavoro verranno presentate misure fluorimetriche e radiometriche, ottenute con un profilatore della Satlantic Inc., che rappresentano i valori di riflettanza superficiale dell’acqua corretti atmosfericamente da satellite. Saranno inoltre presentate le calibrazioni del profilatore ottenute con le alghe Clorella, Laminaria, Fucus vesciculus ed il cianobatterio Spirulina e la correlazione di questi dati con le misure di fluorescenza in situ.
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Conference Abstracts

  • [Nit.EGU2007] D. O. Nitti, F. Bovenga, A. Ganas, R. Nutricato, A. Refice, and M.T. Chiaradia. Refined fault model for the Mw=6.3, June 15, 1995 Aigion EQ (Greece) derived from InSAR data and implications for extensional tectonics of the western Corinth rift. Geophysical Research Abstracts, 9:04866, 2007. SRef-ID: 1607-7962/gra/EGU2007-A-04866. eISSN: 1607-7962.
    On June 15th, 1995, a Mw= 6.3 earthquake struck the western part of the Gulf of Corinth with mainshock epicentre 16 km NNE from Aigion city. The present study presents the application of SAR interferometry (InSAR) techniques for obtaining the co-seismic deformation pattern and inferring the fault model parameters for this seismic event. A second objective is test the Rigo et al., (1996) model for active tectonics of the western Gulf. Both ascending (Track 279, Frame 2835) and descending (Track 415, Frame 765) ERS-1/2 SAR acquisitions were initially selected within 2 years from the mainshock, with the aim of investigating the area affected by the earthquake under different observation directions, different atmospheric conditions and during different seismic activity phases. Standard DInSAR processing was performed in order to produce a stack of differential interferograms. A SRTM DEM of the area was used to remove the topographic component from the interferometric phase. The data time distribution appears suitable for investigating possible pre- and post-seismic activity; however, both pre-shock and after-shock interferograms do not show evidence of any deformation pattern, as the dominant differential phase component seems principally due to atmospheric signal. An in-depth investigation of the co-seismic activity has been instead possible thanks to several suitable interferograms obtained by using both descending and ascending data. In both cases a co-seismic deformation pattern is clearly visible around Cape Psaromita. The spatial distribution of fringes seems in good agreement with that reported in the study of Bernard et al., 1997. However, atmospheric artefacts are recognizable, especially for daytime acquisitions. Therefore, a stacking procedure has been performed in order to filter out the atmospheric signal and to obtain a more reliable deformation pattern. Six complex descending differential interferograms were selected, generated from seven acquisitions acquired between 19 August 1993 and 23 June 1996. After phase offsets correction, a weighted average of the unwrapped interferograms was performed. The resulting differential interferogram contains mainly the temporally correlated displacement signal, while the temporally uncorrelated atmospheric components have been mostly filtered out. By using this refined interferometric pattern of the deformation field, measured along the Line Of Sight (LOS) of the ERS spacecrafts, forward and inversion procedures were performed in order to obtain a new reliable fault model for the Aigion EQ. This single fault plane solution represents a significant improvement of the Okada-like fault models proposed in Bernard et al., (1997), because the effect of the crustal layering of the western Gulf of Corinth was included in the fault model formulation and because of the smaller RMSe between measured and synthetic deformation pattern. Our main findings include: a) the 1995 earthquake did not occur along the onshore Aigion Fault b) the 1995 earthquake occurred along a low angle fault probably with increasing dip towards the surface c) the 1995 earthquake did not rupture the surface and d) the high-angle, antithetic faults of McNeil et al., (2005) terminate against the low angle fault.
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Peer-Reviewed Journal Articles

  • [Kot.ApplOpt2006] S. Y. Kotchenova, E. F. Vermote, R. Matarrese, F. J. Klemm, Jr., "Validation of a New Vector Version of the 6S Radiative Transfer Code for Atmospheric Correction of MODIS Data (Part I)". Applied Optics, Vol. 45, Issue 26, pp. 6762-6774 (2006). DOI: 10.1364/AO.45.006762. ISSN: 1559-128X. eISSN: 2155-3165.
    A vector version of the 6S (Second Simulation of a Satellite Signal in the Solar Spectrum) radiative transfer code (6SV1), which enables accounting for radiation polarization, has been developed and validated against a Monte Carlo code, Coulson’s tabulated values, and MOBY (Marine Optical Buoy System) water-leaving reflectance measurements. The developed code was also tested against the scalar codes SHARM, DISORT, and MODTRAN to evaluate its performance in scalar mode and the influence of polarization. The obtained results have shown a good agreement of 0.7% in comparison with the Monte Carlo code, 0.2% for Coulson’s tabulated values, and 0.001–0.002 for the 400–550 nm region for the MOBY reflectances. Ignoring the effects of polarization led to large errors in calculated top-of-atmosphere reflectances: more than 10% for a molecular atmosphere and up to 5% for an aerosol atmosphere. This new version of 6S is intended to replace the previous scalar version used for calculation of lookup tables in the MODIS (Moderate Resolution Imaging Spectroradiometer) atmospheric correction algorithm. (c) 2006 Optical Society of America
    We thank F.-M. Breon for providing the Monte Carlo code, A. Lyapustin for providing SHARM, G. Anderson for providing MODTRAN, D. Clark for providing the MOBY measurements, F.-M. Breon and A. Lyapustin for multiple discussions and suggestions during this study, and the three anonymous referees for their helpful comments. This work was supported by NASA contract NNG04HZ17C.

  • [Bov.EnGeo2006] F. Bovenga, R. Nutricato, A. Refice, J. Wasowki, "Application of Multi-temporal Differential Interferometry to Slope Instability Detection in Urban/Peri-urban Areas''. Engineering Geology (2006). Volume: 88, Issue: 3-4, Pages: 218-239. DOI: 10.1016/j.enggeo.2006.09.015. ISSN: 00137952.
    We present two case studies regarding the application of Synthetic Aperture Radar (SAR) Persistent Scatterers Interferometry (PSI) techniques to landslide-prone slopes situated in the municipal territories of Caramanico Terme and Volturino (Italy). The analysis of satellite SAR data with PSI techniques poses often problems on sites where, due to the scarcity of human artefacts and the presence of vegetation cover, density of coherent points (PS) is low (b10 per km2). Moreover, the steep and rough topography typical of landslide-prone areas hamper the interferometric pre-processing, making more difficult the joint estimation of displacements and of DEM errors. Under these conditions the significance of temporal interferometric phase trends can be uncertain and conservative assumptions, necessary to ensure low false detection probabilities, need to be coupled with innovative processing strategies to increase the detection efficiency of PS objects. Here, the SPINUA (Stable Point Interferometry over Un-urbanised Areas) processing technique is applied together with an alternative PS Candidate (PSC) selection procedure based on the use of pixels classified as urban. The cases of Caramanico and Volturino are representative, respectively, of harsh and favourable conditions for PSI applications. The results from Caramanico show clusters of PS exhibiting similar line-of-sight (LOS) deformation behaviour in the period 1995–2000. The locations ofmoving PS often coincidewith distressed buildings and appear consistent with the areal distribution of recent and past landslide activity. The temporal displacement trends, however, are characterised by very low annual average velocities (from 3 to 7 mm/y) and it is uncertain to what extent the PS data reflect true slope movements, local deformations (e.g. settlement of engineering structures) or both. Thanks to the more favourable conditions, the application of the standard SPINUA approach in the Volturino area was sufficient to obtain suitable densities of PS, as well as spatially and temporally consistent displacement results for a period 1992–2000. In particular, a group of moving PS was identified in a peri-urban area, known for the past and recent slope stability problems. The slowly moving PS (from 3 to 5 mm/y) fall in a location that, unlike the remaining part of the town, is characterised by the presence of many distressed buildings and structures. Although the site information confirms the reliability of PS data, in the absence of ground monitoring and detailed records of landslide movements, it is difficult to identify the main mechanism of the detected deformations. In general, in geologically and topographically complex urban/peri-urban settings, the significance of very low-velocity PSI surface displacements should always be considered together with in situ geotechnical controls and ground monitoring data.
    This work was supported in part by the European Community (Contract No. EVGI 2001-00055- Project LEWIS) and by the Italian Space Agency (ASI) projects (Contracts No. I/R/27/00 and I/R/073/01). The SPINUA algorithm was developed and tested in the framework of the above-mentioned projects. The ERS images were provided by the European Space Agency under ENVISATAO- 313 and CAT-1 Id:2653 projects.We also thank the administrations of Regione Abruzzo, Caramanico and Volturino Municipalities for their support. Continuous support and numerous discussions with Prof. Luciano Guerriero are gratefully acknowledged. The authors acknowledge the POLIMI group, and in particular Carlo Colesanti and Alessandro Ferretti, for helpful discussions on the Permanent Scatterers. Finally, we thank Paolo Farina,VincenzoDel Gaudio and an anonymous reviewer for their helpful comments.

  • [Ref.TGRS2006] A. Refice, F. Bovenga, R. Nutricato, "MST-based stepwise connection strategies for multi-pass radar data, with application to co-registration and equalization". IEEE Transactions on Geoscience and Remote Sensing (2006). Volume: 44, Issue: 8, Pages: 2029-2040. ISSN: 01962892. DOI: 10.1109/TGRS.2006.872907.
    This paper proposes a unified framework for predicting optimized pairing strategies for interferometric processing of multipass synthetic aperture radar data. The approach consists in a minimum spanning tree (MST) structure based on a distance function encoding an a priori model for the interferometric quality of each image pair. Using a distance function modeled after the interferometric coherence allows reproducing many “small baseline” strategies presented in the recent literature. A novel application of the method to the processing steps of image coregistration and equalization is illustrated, using a test European Remote Sensing Satellite dataset.Widespread methods used for these two operations rely on the computation of the amplitude cross correlation over a large number of corresponding tie patches distributed over the scene. Geometric shift and radiometric equalization parameters are estimated over the patches and used, respectively, within a polynomial warp model and a radiometric correction scheme. The number of reliable patches available behaves similarly to the interferometric synthetic aperture radar (InSAR) coherence with respect to the baselines, and can be assimilated to a quality figure for the derivation of theMST. Results show an improvement in the quality of the stepwise (SW)-processed image stack with respect to the classical single-master procedure, confirming that the SW approach is able to provide better conditions for the estimation of correlation-related InSAR parameters.
    The authors thank L. Guerriero (Politecnico di Bari, Italy) for the many ideas and discussions about the subject of this paper. J. Wasowski (CNR-IRPI) and A. Blonda (CNR-ISSIA) are acknowledged for kind permission of using the data, obtained through the ENVISAT and ERS ESA-AO projects. Finally, the authors would like to thank the anonymous reviewers whose insightful observations and suggestions greatly helped to improve the quality of the paper.

International Conference Proceedings

  • [Nit.IGARSS2006] D. O. Nitti, F. Bovenga, R. Nutricato, A. Refice, and M.T. Chiaradia. InSAR derived deformation patterns related to the Aigion earthquake (Greece). In Proceedings of International Geoscience and Remote Sensing Symposium, Denver, Colorado, USA, Jul. 31-Aug. 4, 2006. DOI: 10.1109/IGARSS.2006.403. ISSN: 2153-6996. Print ISBN: 0-7803-9510-7. Scopus: 2-s2.0-34948841382. WOS:000260989400398
    The detectability of the deformation pattern produced by the June 15, 1995 Aigion Earthquake with DInSAR techniques is ensured by its magnitude (MW = 6.3), shallow depth and dip-slip mechanism. In this paper, stacking procedures are applied to a series of ERS interferograms in order to filter out from the differential phase field the atmospheric signal, and an a posteriori test is used to check the statistical properties of the atmospheric signal both in time and space. Based on the DInSARderived deformation pattern, a new fault model is proposed that takes into account the crustal layering of the western part of the Gulf of Corinth.
    The authors thank Dr. Athanassios Ganas from the National Observatory of Athens for the helpful technical hints. This work was supported in part by the European Community (Contract EVGI 200-00055 - Project LEWIS). Data provided by European Space Agency under the CAT-1 project n. 2653.

National Conference Proceedings

  • [Nit.GOLD2006] D. O. Nitti, F. Bovenga, R. Nutricato, A. Refice, and M.T. Chiaradia. Refined InSAR derived fault model for the Mw=6.3, June 15, 1995 Aigion EQ (Greece). In Proceedings of IEEE GOLD Remote Sensing Conference, Bari, Italy, December 4-5, 2006. ISBN 978-889591118-2.
    The detectability of the deformation pattern produced by the June 15, 1995 Aigion Earthquake with DInSAR techniques is ensured by its magnitude (MW = 6.3), shallow depth and dip-slip mechanism. In this paper, stacking procedures are applied to a series of ERS interferograms in order to filter out from the differential phase field the atmospheric signal, and an a posteriori test is used to check the statistical properties of the atmospheric signal both in time and space. Based on the DInSARderived deformation pattern, a new fault model is proposed that takes into account the crustal layering of the western part of the Gulf of Corinth.
    The authors thank Dr. Athanassios Ganas from the National Observatory of Athens for the helpful technical hints. This work was supported in part by the European Community (Contract EVGI 200-00055 - Project LEWIS). Data provided by European Space Agency under the CAT-1 project n. 2653.

  • [Mat.GOLD2006] R. Matarrese, M. Acquaro, A. Morea, K. Tijani, M.T. Chiaradia, "Applications Of Remote Sensing Techniques For Mapping Posidonia Meadows". In Proceedings of IEEE GOLD Remote Sensing Conference, Bari, Italy, December 4-5, 2006. ISBN 978-889591118-2.
    Monitoring marine benthic communities is generally considered to be an essential activity to increase understanding and hence the correct management of coastal areas. Seagrass ecosystems protect shorelines against erosion and are efficient in removing nutrients from marine waters and surface sediments. Therefore they are an important element in improving the water quality of coastal waters. Remote sensing techniques offer one solution to the problem of surveying the extent and development of benthic communities by offering synoptic information over large spatial scales. A large variety of approaches may be used to map seagrasses. The selection of sensor imagery and of a classification method is related to the features of investigated area, the lower limit of the communities (maximal depth), the degree of precision required and the cost-effectiveness in relation to time spent, [1]. In this study, thematic maps of sea bottom habitats are produced from different remote sensing sensors' data (Landsat ETM+, ASTER), and with a Maximum Likelihood classification method. A comparison with ground truth measurements in the Ionian Sea shows the advantages and the limits of each approach, according to a reliability scale suggested by Pasqualini V. et al. in 1997 [2].
    This research is carried out by Physics Dept.-Politecnico of Bari in the framework of IMCA project in Puglia, Italy, supported by MIUR with the collaboration of the Biologic Dept. of University of Bari.

Conference Abstracts

  • [Gan.HAZARDS2006] A. Ganas, D.O. Nitti, F. Bovenga, R. Nutricato, A. Refice and G. Papadopoulos. “Improved fault model of the 1995 Aigion earthquake retrieved from ERS InSAR data.” 11th International Symposium on Natural and Human Induced Hazards and 2nd Workshop on Earthquake Prediction Abstract Volume, June 22-25, 2006, Patras, Greece, pag.40.
    This work aims at the application of SAR interferometry (InSAR) techniques for obtaining the co-seismic deformation pattern of the June 15, 1995 M=6.2 earthquake and inferring the fault model parameters for this seismic event. InSAR thanks to its large-area coverage of the deformation field provides useful measurements for damage assessment of seismic events and fault modelling. Standard InSAR processing was performed through the DORIS software in order to produce a stack of differential interferograms. A void-filled, SRTM-derived DEM was used to remove the topographic component from the interferometric phase. A new Okada-like fault solution is proposed, which is derived by inverting displacement obtained through InSAR stacking procedures, as well as the present knowledge on the crustal layering in the western Gulf of Corinth. In addition, the r.m.s. computed on the difference between the refined deformation pattern and the synthetic deformation pattern obtained according to the new parameters is better than that reported in previous studies. The solution includes the most critical focal parameters such as fault strike (277), dip direction (N7E), dip angle (31), Centroid depth (7.6 km), and seismic moment. Further refinements could be obtained by assuming a more complicated fault model consisting of many planes with different geometries. The implications for extensional tectonics of the western Gulf of Corinth are also discussed.
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  • [Gue.EGU2006] L. Guerriero, F. Bovenga, R. Nutricato, J. Wasowski, D. Casarano, P. Gostelow, V. Del Gaudio, P. Blonda, A. Refice, "Developing a Landslide Early-Warning System based on satellite measurements", Geophysical Research Abstracts, Vol. 8, 07362, 2005 SRef-ID: 1607-7962/gra/EGU06-A-07362, European Geosciences Union 2006, Wien, Austria, 02-07 April 2006. eISSN: 1607-7962.
    This contribution presents some results of LEWIS (Landslide Early Warning Integrated System) project supported by the European Commission and concluded in 2005. The prime objective of the proposed research was to develop an approach which increases and promotes the value of comparatively low-cost, wide-area satellite data as an input to the assessment of hazard and risk from ground movements. The key element in the LEWIS project is to avoid trying to infer absolute values of relevant geophysical parameters from Earth Observation (EO) data, but only their changes in time in the wider sense of “deviations from a known temporal evolution model”. Other periodic information can be obtained from existing ground networks, e.g. for rain and earthquakes. The detected changes have to be integrated into a Geographic Information System (GIS), together with other more static parameters, and used to infer potential slope stability changes and to produce early warning. The output product of the LEWIS project can be defined as an updateable slope instability susceptibility map, based on changes detected from moderate resolution EO data.The approach has been based on the well known principle that either an increase of shear stresses and/or the decrease of effective material shear strengths over a period of time are the primary cause of increasing susceptibilities to slope instability, thus contributing to first-time failures or reactivated movements on pre-existing slip surfaces. The complementary expertise of the geologic and the Earth observation components of the project team allowed to define a geotechnical model suitable for the spatial/ temporal resolution and for the precision of the EO change measurements. The geotechnical inference model firstly uses GIS topographic and geological ground data (a slope map derived from a Digital Elevation Model, a previous landslide map, a description of the lithological classification distinguishing between soil and rocks, and a brittleness index, reflecting the stress-strain behaviour of the engineering soils) to identify potential levels of susceptibility to deformation in slopes which are close to a factor of safety of 1.0, i.e. they are susceptible to mass movement. Secondly it integrates land use change maps derived by EO data to show levels of warning with respect to that deformation. The methodology used for the production of the land use change maps is based on advanced artificial intelligence techniques, i.e. neural networks classifiers and fuzzy logic and it follows three different approaches to change detection: a supervised approach, an unsupervised approach and a hybrid approach. SAR Interferometry techniques based on Persistent Scatterers (PS) approach are used to give a warning signal through the detection of precursory movements, which may give rise to conditions leading to landslides, since the PS-detected slow ground deformations can indicate ongoing ground instability. After in situ validation the PS data indicative of movements at an average velocity equal or greater than 3 mm/year, can be added to the change-based model output in the warning map as a direct indicator of potential instability. The stable PS can also be taken into account and interpreted as signals that strongly indicate areas of ground stability. The final result of the LEWIS project is a working prototype of a landslide early warning system, designed to cover regional areas. The prototype has been validated with encouraging results on two Italian test sites originally selected for the experiment. The verification of the approach on a third test site, in Greece, is still under way.
    This work was supported in part by the European Community (Contract No. EVGI 2001-00055 - Project LEWIS).

  • [Was.EGU2006] J. Wasowski, F. Bovenga, D. Casarano, R. Nutricato, A. Refice, "Tracking And Interpreting Ground Surface Deformations Detected With PSI Techniques in Landslide-Prone Hilltop Towns: Case Study From Italy", Geophysical Research Abstracts, Vol. 8, 05911, 2005 SRef-ID: 1607-7962/gra/EGU06-A-05911, European Geosciences Union 2006, Wien, Austria, 02-07 April 2006. eISSN: 1607-7962.
    By applying the Persistent Scatterers Interferometry (PSI) techniques to the currently available satellite radar imagery, it possible to detect and monitor very slow displacements (from millimetres to centimetres per year), occurring on selected point targets (PS) exhibiting coherent radar backscattering properties (mainly buildings and other man-made structures). In this study we focus on some difficulties in interpreting the exact geological/geotechnical origin of the PSI results obtained by applying the SPINUA algorithm to ERS1and2 radar data. The work, conducted in the framework of the EU project LEWIS, regards the Daunia region (Southern Apennines), which includes several isolated small hilltop towns affected by slope instability problems. Examples from Daunia urban/peri-urban areas are used to illustrate that, when very slowly moving PS are detected on hillslope areas, this does not necessarily mean that their motions represent slow landslide movements. In general, on slopes, surface displacements over time might be found to be in a downslope direction but such deformations might not necessarily always reflect shear movements or movements leading to shear failure, i.e. to landsliding. The interpretation of PS displacement data on urbanised hillslopes is further complicated, because their movements may arise from a variety of natural or anthropogenic processes and thus may reflect complex deformation mechanisms. Indeed, with the exception of “natural” PS (e.g. corresponding to rock outcrop target), without an appropriate in situ investigation, several different interpretations of the very slow PS displacements are possible: i) deterioration of manmade structures, ii) settlement of engineering structures, iii) volumetric strains within soils, iv) natural or anthropogenic subsidence or uplift, v) extremely slow slope deformations that may or may not lead to failure. The recent PS results showing ground surface deformation changes over time on landslide susceptible slopes are very promising, but the geotechnical parameter and geological boundary uncertainties which control them need to be investigated and better understood before they can be confidently used directly for landslide hazard/risk zonation or for predicting (warning) of potential instabilities. Further research is certainly needed using the technique on test areas with different geological and geomorphological scenarios and giving more attention to the structural behaviour of man-made objects that act as PS targets.

    This work was supported in part by the European Community (Contract No. EVGI 2001-00055 - Project LEWIS). Images were provided by ESA under the CAT-1 project number 2653, “Advanced SAR Interferometry techniques for landslide warning management”.


Anni Precedenti

  1. J. WASOWSKI, F. BOVENGA, D. CASARANO, R. NUTRICATO, A. REFICE, "Application of PSI techniques to landslide investigations in the Caramanico area (Italy): lessons learnt", Proc. of FRINGE 2005, November 28 - December 1, 2005, Frascati, Italia.
  2. F. BOVENGA, M. T. CHIARADIA, R. NUTRICATO, A. REFICE, J. WASOWSKI, "Application of PSI techniques to slope instability detection in the Daunia mountains, Italy", Proc. of FRINGE 2005, November 28 - December 1, 2005, Frascati, Italia.
  3. A. REFICE, F. BOVENGA, R. NUTRICATO, M. T. CHIARADIA, J. WASOWSKI, "Land-cover classification-based Persistent Scatterers identification for peri-urban applications" , IEEE IGARSS 2005, Proc. of IGARSS 2005, July 25-29 2005, Seoul, Korea.
  4. L. GUERRIERO, F. BOVENGA, R. NUTRICATO, A. REFICE, J. WASOWSKI, "The role of PS Interferometry in the Landslide Early Warning Integrated System (LEWIS) Project.", Proceedings Workshop di Telerilevamento e dissesto idrogeologico, 7-8 July 2005, Cagliari - Italy.
  5. L. GUERRIERO, F. BOVENGA, R. NUTRICATO, A. REFICE, J. WASOWSKI, V. DEL GAUDIO, P. MANUNTA, "Il Progetto LEWIS ed il ruolo della tecnica dei Riflettori Permanenti nel monitoraggio dei pendii instabili", Rivista Italiana di Agrometeorologia anno 9 n.1 Febbraio 2005 - Atti del Convegno AIAM 2005, Agrometeorologia, risorse natuali e sistemi di gestione del teritorio, 3-5 maggio 2005 Caramanico-Vasto, Italia. (Rivista Nazionale)
  6. F. BOVENGA, V. SINGHROY, J. WASOWSKI, "Exploting different radar sensors and InSAR techniques for slope instability monitoring", Geophysical Research Abstracts, Vol. 7, 10892, 2005 SRef-ID: 1607-7962/gra/EGU05-A-10892 European Geosciences Union 2005, Wien, Austria, 24-29 April 2005.
  7. J. WASOWSKI, M. SORGENTE, M. SAVIO, G. LOLLINO, F. GODONE, V. DEL GAUDIO, F. BOVENGA, M. BALDO, "Detection of premonitory slow ground deformations on landslide-prone slopes through GPS and DInSAR techniques: a case study from Italy", Geophysical Research Abstracts, Vol. 7, 07454, 2005 SRef-ID: 1607-7962/gra/EGU05-A-07454 European Geosciences Union 2005, Wien, Austria, 24-29 April 2005.

  1. A. REFICE, F. BOVENGA, R. NUTRICATO, M. T. CHIARADIA, "Assessment of Multitemporal DInSAR Stepwise Processing", IEEE IGARSS 2004, Proc. of IGARSS 2004, September 20-24 2004, Anchorage, Alaska.
  2. F. BOVENGA, A. REFICE, R. NUTRICATO, L. GUERRIERO, M. T. CHIARADIA, "SPINUA: a flexible processing chain for ERS / ENVISAT long term interferometry", Proceedings of ESA-ENVISAT Symposium 2004, 6-10 September, 2004, Saltzburg, Austria.
  3. N. VENEZIANI, V. M. GIACOVAZZO, F. BOVENGA, "Height Retrieval by Using a Pseudo-Differential Approach in SAR Interferometry: Preliminary Results", IEEE IGARSS 2004, Proc. of IGARSS 2004, September 20-24 2004, Anchorage, Alaska.
  4. F. BOVENGA, R. NUTRICATO, A. REFICE, J. WASOWSKI, "Application of Multitemporal Differential Interferometry to Landslide Investigations in peri-urban areas" , Geophysical Research Abstracts of European Geoscience Union I General Assembly, Nice, France, 25-30 April 2004.

  1. J. WASOWSKI, F. BOVENGA, R. NUTRICATO, A. REFICE, D. CASARANO, "Test of Applicability of Multitemporal Differential Interferometry Analysis to Landslide Investigations in Peri-Urban Areas", Proceedings of FRINGE'03, ESA-ESRIN, Frascati, Italy, 1-5 December, 2003.
  2. A. REFICE, F. BOVENGA, R. NUTRICATO, "Stepwise Approach to InSAR Processing of Multitemporal Datasets", Proceedings of FRINGE'03, ESA-ESRIN, Frascati, Italy, 1-5 December, 2003.
  3. F. BOVENGA, S. STRAMAGLIA, R. NUTRICATO, A. REFICE, "Discrimination of different sources of signals in Permanent Scatterers technique by means of Independent Component Analysis", IEEE IGARSS 2003, Proc. of IGARSS 2003, July 21-25 2003, Toulouse, France.
  4. N. VENEZIANI, F. BOVENGA, A. REFICE, "A Wide-Band approach to Absolute Phase Retrieval in SAR interferometry", Multidimensional Systems and Signal Processing, MULT Vol 14 Nos 1-2, Kluwer Academic Publishers, Netherlands 2003.
  5. F. MATTIA, A. M. GATTI, G. PASQUARIELLO, G. SATALINO, F. POSA, A. D'ALESSIO, C. NOTARNICOLA, M. RINALDI, T. LE TOAN, G. PICARD, "Preparing ENVISAT campaign: radar and ground measurements on wheat fields over the Matera test site " in Rivista Italiana di TELERILEVAMENTO, 26,27,28 , 77-82 (2003).
  6. F. BOVENGA, A. REFICE, S. STRAMAGLIA, D. CONTE, "Phase unwrapping by means of scaling information and global optimization algorithms". Proceedings of the SPIE International Society for Optical Engineering 4883, 162-170 (2003).

  1. F. BOVENGA, A. REFICE, R. NUTRICATO, G. PASQUARIELLO, G. DE CAROLIS, "Automated Calibration of Multi-Temporal ERS SAR Data", IEEE IGARSS 2002, Proc. of IGARSS 2002, June 24-28 2002, Toronto, Canada.
  2. R. NUTRICATO, F. BOVENGA, A. REFICE, "Optimum Interpolation and Resampling for PSC Identification", IEEE IGARSS 2002, Proc. of IGARSS 2002, June 24-28 2002, Toronto, Canada.
  3. J. WASOWSKI, A. REFICE, F. BOVENGA, R. NUTRICATO, "On the Applicability of SAR Interferometry Techniques to the Detection of Slope Deformations", Proceedings of 9th IAEG Congress, Durban, South Africa, 16-20 September 2002.
  4. A. REFICE, F. BOVENGA, S. STRAMAGLIA, D. CONTE, "Use of scaling information for stochastic atmospheric absolute phase screen retrieval", IEEE IGARSS 2002, Proc. of IGARSS 2002, June 24-28 2002, Toronto, Canada.
  5. F. BOVENGA, A. REFICE, S. STRAMAGLIA, D. CONTE, "Phase Unwrapping by means of scaling information and global optimization algorithms", Proc. of 9th International Symposium on Remote Sensing, 22-27 Septeber 2002 Aghia Pelagia, Crete, Grecia.

  1. A. REFICE, F. BOVENGA, J. WASOWSKI, L. GUERRIERO, "Use of InSAR Data for Landslide Monitoring: A Case Study from Southern Italy". IEEE IGARSS 2001, Proc. of IGARSS 2001, 09-13 July 2001, Sydney, Australia.
  2. A. REFICE, F. BOVENGA, R. NUTRICATO, J. WASOWSKI, P. BLONDA, G. SATALINO, "Unstable slopes monitoring by Remote Sensing", presented at the NATIONAL WORKSHOP "Getting ready for ENVISAT", 30-31 Maggio e 1 Giugno 2001 - Matera, Centro di Geodesia Spaziale.
  3. A. REFICE, F. BOVENGA, J. WASOWSKI, "Monitoring landslide activity in a peri-urban area by SAR Interferometry". Geophysical Research Abstracts of European Geophysical Society XXVI General Assembly, Nice, France, 25-30 March 2001, Vol. 3.
  4. L. GUERRIERO, A. REFICE, S. STRAMAGLIA, G. SATALINO, N. VENEZIANI, P. BLONDA, M. T. CHIARADIA, "Global Approaches and Local Strategies for Phase Unwrapping". Il Nuovo Cimento, Vol. 24, N.1, Jan. 2001, pp. 11-23.
  5. N. VENEZIANI, F. BOVENGA, F. LOVERGINE, A. REFICE, "Resolution of height ambiguities in DEMs obtained from SAR Interferometry". Proc. of Int. Workshop on Geo-Spatial Knowledge Processing for Natural Resource Management, June 28-29, 2001, Varese, Italy.

  1. A. REFICE, F. BOVENGA, J. WASOWSKI, L. GUERRIERO, N. VENEZIANI, S. ATZORI, A. R. FERRARI, M. MARSELLA, "Detecting Landslide Landslide Activity by SAR Interferometry". Proc. of ERS-ENVISAT Symposium, 16-20 October 2000, Gothenburg, Sweden.
  2. A. REFICE, F. BOVENGA, J. WASOWSKI, L. GUERRIERO, "Using InSAR Data for Landslide Monitoring: a Case Study from Southern Italy". IEEE IGARSS 2000, Proc. of IGARSS 2000, 24-28 july 2000, Honolulu, Hawaii USA.
  3. N. VENEZIANI, F. BOVENGA, F. LOVERGINE, A. REFICE, "A Frequency-domain differential approach to the absolute phase retrieval in SAR interferometry". IEEE IGARSS 2000 , Proc. of IGARSS 2000, 24-28 july 2000, Honolulu, Hawaii USA.
  4. A. REFICE, F. BOVENGA, "Landslide Studies by SAR Differential Interferometry: a Case Study in Southern Italy". Geophysical Research Abstracts of European Geophysical Society XXV General Assembly, Nice, France, 25-29 April 2000.
  5. P. BLONDA, G. SATALINO, A. BARALDI, F. BOVENGA, A. REFICE, "Multitemporal SAR Intensity and Interferometric coherence data fusion". Proc. of III Fusion of Earth Data Symposium, Sophia Antipolis, 26-28 Gennaio 2000.
  6. S. STRAMAGLIA, A. REFICE, L. GUERRIERO, "Statistical mechanics approach to the phase unwrapping problem". Physica A vol. 276, n. 3-4. Feb. 2000, pp. 521-534
  7. G. NICO, M. PAPPALEPORE, G. PASQUARIELLO, A. REFICE, S. SAMARELLI, "Comparison of SAR amplitude vs. coherence flood detection methods - A GIS application". International Journal of Remote Sensing 21(8): 1619-1631, 2000.

  1. S. STRAMAGLIA, L. GUERRIERO, G. PASQUARIELLO, N. VENEZIANI, "Mean Field Annealing for phase unwrapping". Applied Optics, N. 38, pp. 1377-1383, March 1999.
  2. A. REFICE, G. SATALINO, S. STRAMAGLIA, M. T. CHIARADIA, N. VENEZIANI, "Weights determination for minimum cost flow InSAR phase unwrapping". IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293), 1999, pt. 2, p 1342-4 vol.2.
  3. S. STRAMAGLIA, G. NICO, F. LOVERGINE, L. GUERRIERO, "InSAR phase unwrapping algorithm based on mean-field theory". IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293), 1999, pt. 2, p 1345-7 vol.2

  1. L. GUERRIERO, G. NICO, G. PASQUARIELLO, S. STRAMAGLIA, "A new regularization scheme for phase unwrapping". Applied Optics, 37(14), 3053-3058, (1998) tar file (including figures)
  2. M. T. CHIARADIA, L. GUERRIERO, A. REFICE, G. PASQUARIELLO, G. SATALINO, S. STRAMAGLIA, "Phase unwrapping as an ill-posed problem: performance comparison between a neural network based approach and a stochastic search method". Proceedings of the SPIE - The International Society for Optical Engineering, v 3455, p 2-11, 1998.
  3. A. REFICE, M. T. CHIARADIA, L. GUERRIERO, G. NICO, P. N. BLONDA, G. PASQUARIELLO, G. SATALINO, S. STRAMAGLIA, N. VENEZIANI, "Local and global strategies for InSAR phase unwrapping". Proceedings of the SPIE - The International Society for Optical Engineering, v 3497, p 134-45,1998.
  4. S. STRAMAGLIA, G. PASQUARIELLO, L. GUERRIERO, A. DISTANTE, "Interferometric SAR phase unwrapping by parallel tempering on a APE100/Quadrics", LECTURE NOTES IN COMPUTER SCIENCE, Volume: 1401, Pages: 898-900, 1998.
  5. S. STRAMAGLIA, G. PASQUARIELLO, L. GUERRIERO, A. DISTANTE, "Interferometric SAR phase unwrapping by parallel tempering on a APE100/Quadrics supercomputer". High-Performance Computing and Networking. International Conference and Exhibition. Proceedings, 1998, p 898-900.

  1. A. REFICE, G. SATALINO, "Assessment of a neural network approach to the phase unwrapping problem for the SAR interferometry", ERUDIT - European Symposium on Intelligent Techniques, Bari, Italy, 20-21 March 1997, pp. 157-160.
  2. S. STRAMAGLIA, G. NICO, G. PASQUARIELLO, L. GUERRIERO, "Phase unwrapping method based on stochastic relaxation", Proceedings on Aerospace and Remote Sensing , London, 22-26 September 1997, vol. 3217. Postscript file (including figures)
  3. S. STRAMAGLIA, G. NICO, G. PASQUARIELLO, L. GUERRIERO, "Phase unwrapping method based on stochastic relaxation". Proceedings of the SPIE - The International Society for Optical Engineering, v 3217, 1997, p 4-12
  4. A. REFICE, G. SATALINO, M. T. CHIARADIA, "Local residue coupling strategies by neural network for insar phase unwrapping", Proceedings on Aerospace and Remote Sensing , London, 22-26 September 1997, vol. 3217. Postscript file (including figures).
  5. G. NICO, A. REFICE, L. GUERRIERO, N. VENEZIANI, "A new algorithm for interferometric DEM geocoding", Proceedings on Aerospace and Remote Sensing, London, 22-26 September 1997, vol. 3217.tar file (including figures).

  1. L. GUERRIERO, G. PASQUARIELLO, N VENEZIANI, A. REFICE, M. T. CHIARADIA, "Absolute phase determination in SAR interferometry". Proceedings of the International Geoscience and Remote Sensing Symposium (IGARSS '96), pp. 2060-2062, Lincoln, Nebraska, 27-31 May 1996.
  2. L. GUERRIERO, G. PASQUARIELLO, N VENEZIANI, A. REFICE, M. T. CHIARADIA, "Phase unwrapping techniques for INSAR". Symposium on Satellite Remote Sensing III, Vol. 2958, pp. 262-272, Palazzo dei Congressi, Taormina, Italy, 23-27 September 1996.



 


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