Geological Remote Sensing Group – GRSG

Abstract

Impact of Sentinel-1 data on surface deformation monitoring over large areas

M. Bianchi, S. Cespa, A. Ferretti, A. Fumagalli, F. Novali; TRE – Tele-Rilevamento Europa, Milan Italy

The impressive results of the co-seismic interferogram of the Nepal earthquake last April have already confirmed the value of Sentinel-1A radar data for surface deformation monitoring over large areas. The Interferometric Wide Swath acquisition mode can image a 250-km swath, more than twice that of the ESA ERS mission, with a repeat cycle of 12 days: a breakthrough for large scale monitoring programs. Apart from the space segment, multi-interferogram InSAR algorithms (such as PSInSAR and SqueeSAR) developed in the last decade have finally reached a level of maturity to be used as a standard technology for environmental monitoring, similarly to GPS or weather data. Cloud computing and storage capabilities are also keeping pace with the growing number of satellite sensors for Earth Observation and are already impacting on remote sensing projects.

All these three elements, i.e. Sentinel-1 data over large areas, powerful and reliable algorithms for radar data processing, and computational power, make it possible to open new ways towards effective environmental monitoring plans, and to satisfy the growing demand of final users for near real-time results.

In this study, we present some SqueeSAR results obtained by processing Sentinel-1 data that show a good spatial coverage of Point-wise and Distributed Scatterers over different kinds of terrain.
The regular acquisition of high-quality SAR images with short repeat-cycles can make Sentinel the best information source, in particular for governmental agencies and users involved in the management of large areas. The ability to detect ground displacements occurred over hundreds or thousands of square kilometres, and even at a national scale, can be extremely useful in characterising areas prone to risk, such as highlighting areas affected by sliding and subsidence phenomena. InSAR data can now allow decision makers analysing and evaluating different scenarios, and planning specific actions based on homogeneous and reliable measurements.