基于哨兵数据相干性的洪水淹没范围确定方法

洪涝灾害会造成农田淹没、居民住宅损毁等危害，因此对洪水淹没范围进行实时、准确监测可有效进行灾后治理。利用光学传感器提取洪水淹没范围时，不能穿透云层，因此无法获取有效地面信息；而SAR使用微波波段，不受天气影响，在夜间也能成像。因此，SAR成为洪水灾害灾情评估的有力工具。本文利用2021年9月23日、10月5日、10月17日3景SAR雷达影像Sentinel-1A数据，计算相干性系数，设置阈值为0.2,提取水体淹没范围，分析其扩张范围及变化趋势，并根据生成的形变图分析水位抬升变化，验证了基于雷达数据的相干系数阈值提取方法监测洪水淹没范围，以及采用InSAR技术准确提取水体边界与分析水位上升趋势的可行性。

The determination method of flood inundation range based on the coherence of Sentinel data

Flood disaster can cause farmland inundation, residential damage and other hazards. When the optical sensor extracts the flooded area, it can't penetrate the clouds, so it can't get effective ground information. SAR uses microwave band, which is not affected by weather conditions and can be imaged at night. Therefore, SAR has become a powerful tool for flood disaster assessment. This paper uses Sentinel-1A data of three SAR radar images on September 23, October 5 and October 17, 2021 to calculate the coherence coefficient. The threshold value is set to 0.2 to extract the water inundation range, and the expansion range and change trend are analyzed. According to the generated deformation map, the change of water level rise is analyzed. It is confirmed that the coherence coefficient threshold extraction method based on radar data is feasible in monitoring the flood inundation range. It is verified that InSAR technology can accurately extract water boundary and analyze water level rising trend.