Monitoring Water Area Variation of the Po River Using Dual-Polarimetric SAR Data

In this study, dual-polarimetric (DP) Synthetic Aperture Radar (SAR) time series collected by the Sentinel-1 SAR mission is exploited to evaluate the changes that occurred over the surface water area of the Po River, in Italy. First, a DP technique based on an incoherent combination of co–and cross-polarized SAR channels are used to enhance the separability between surface river water and land areas. Then, a binary image where the river and the land area are well separated is generated using a constant false alarm rate (CFAR) detector. Once the water-covered area is estimated, an in-depth analysis based on the Shannon entropy is applied to understand the time variability of the water extension of the Po River. Experimental results show that the dual-polarimetric approach can effectively monitor the water body changes that occurred over the river Po basin in an effective way.