Synergistic Use of COSMO-SkyMed and Sentinel-1 Data for Costal Flood Analyses.

In this study, we show the potential of a synergistic use of COSMO-SkyMed (CSK) and Sentinel-1 (S-1) synthetic aperture radar (SAR) data for the analysis of ground deformations in coastal regions potentially subjected to flood risk. The global climate change and the inherent increase of the mean sea level exacerbate the risk. In this work, we want to focus on the capability of high-resolution CSK images, combined with medium-resolution Sentinel-1 data, to jointly provide a more comprehensive view of the changes occurring in highly urbanized coastal regions, such as the one represented by the megacity of Shanghai. Specifically, we have applied a split-spectrum method to identify a set of highly coherent SAR pixels. The location and spatial density of such permanent (and the semipermanent scatters) have revealed helpful to generate a flood risk map for the coastal area of Shanghai in a worst-case scenario. To this aim, we have used the LISFLOOD-FP hydrodynamic model to forecast possible inundation patterns and used the estimated density of high-coherent SAR pixels into the inundated areas to quantify the coastal flood impacts. Similar analyses could also be extended to other coastal regions in the World, as the West Coast of U.S.