Remote sensing monitoring and evaluation of flood disaster in Fugou County of Henan Province based on Sentinel-1 and Sentinel-2 images

Flood disasters are the most important of the types of natural disasters with high frequency and wide impact, posing a serious threat to social and economic development and the safety of people’s lives and property. The experiment selected Fugou County of Zhoukou City, which was heavy hit by the "7.20" exceptionally heavy rainstorm event in Henan Province as the research area, selected the sentinel-1 and Sentinel-2 images before and after the flood disaster as the main data sources, used the SVM to classify the land use of the sentinel-2 image before the disaster and quickly extracted the water body area during and after the disaster on the Sentinel-1 image based on the SDWI dual polarization water index method, and combined with the GIS to evaluate the disaster situation in the research area. The results show that: ① The overall accuracy of the land use classification map extracted based on the SVM is 95.85%. ② The results of the water body range extracted using the SDWI water body index method show that the water body area during and after the disaster is 36.468 km² and 18.770 km²,and the overall accuracy is 97.6% and 95.4%. ③ The extraction results show that Caoli Township was the most seriously affected with the maximum water body change area of 12.63 km².