Differential Interferometry over Sentinel-1 TopSAR Images measuring earth surface deformationsa tool for water and tillage soil erosion analysis in agricultural basins

Résumé

Erosion is a major problem on agricultural land in Europe. Erosion measurement tools have traditionally been focused on delocalized quantification but without mapping the real places inside the basin where erosion took effect. In this research, we take advantage of new space missions like Sentinel-1 and the opportunity it offers to obtain SAR (Synthetic Aperture Radar) images with high frequency, resolution, range and, above all, availability, which allows the use of techniques like differential interferometry in new fields. Accordingly, we propose measuring earth surface deformation caused by water and tillage erosion in small agricultural basins using TopSAR (Terrain Observation with Progressive Scans SAR, Synthetic Aperture Radar) images acquired by the Sentinel-1 mission, after previously proving the accuracy of these measurements by comparing with measurements of the gold standard laser-based terrestrial LIDAR (Light Detection and Ranging) system. The results of the present work show that erosion monitoring in agricultural basins with differential interferometry over Sentinel-1 TopSAR images is possible and differences between the differential interferometry and LIDAR results are within the range of the error associated with the very LIDAR system. Its capabilities have been tested successfully under different conditions related to agricultural work with and without precipitation or storm events. It makes it possible not only to study erosion and sedimentation processes but also the efficiency of antierosion measures, which can be tested in the field. In addition, the results of different management practices can be checked over time.