Rapid monitoring and analysis of Weihui flood using Sentinel-1A SAR data

This Flood disasters, with their high frequency and major hazards, seriously endanger the safety of human life and property. Therefore, flood monitoring is of great importance. Synthetic aperture radar (SAR) is not affected by clouds and rain, and obtain effective data for flood monitoring. In July 2021, Weihui City encountered heavy rainfall, causing severe flooding. This paper selects the Sentinel-1A SAR data of Weihui City before the flood (July 15), during the flood (July 27) and after the flood (August 8), and uses the object-oriented threshold method to extract the water body information, and conduct the flood inundation area monitoring and analysis. The results demonstrate that the use of Sentinel-1A data based on the object-oriented threshold method can achieve rapid monitoring of flood areas. Before the flood occurred in the main urban area of Weihui City, the water body coverage area is 4.18 km(2), and the water body coverage area is 45.72 km(2) during the flood disaster. After the flood receded, the coverage area of the water body is reduced to 15.98 km(2). This indicates that the method proposed in this paper can effectively extract the coverage of water body and provide a reliable technical means for flood monitoring.