Abstract:

Based on the Synthetic Aperture Radar (SAR) remote sensing image data from the Sentinel−1 earth observation satellite, meteorological, disaster, crop and other multi−source data, the regional monitoring method of flood disaster of summer maize based on Sentinel−1 Dual Polarized Water Index (SDWI) was established. Taking county−level administrative units as the research object, the inundation information of flood disasters of summer maize was extracted. The inundation area of summer maize caused by flood in each town of each county−level unit was determined. The dynamic monitoring and disaster assessment during the jointing－maturity stage of summer maize in 2021 in Xun county, Henan province were carried out. The results indicated that: (1) the regional monitoring method of flood disaster of summer maize based on SDWI index could effectively monitor the occurrence and development process of flood disaster of summer maize in Xun county. The monitoring results showed that during the jointing−maturity stage of summer maize in 2021, the flood disasters mainly occurred in the central and southern parts of Xun county, which had significant impacts on summer maize in Baisi town and Xiaohe town. (2) The flood disaster had significant impacts on summer maize, with severe damage observed throughout the study area. The maximum affected area reached 4043.60×10⁴m². Compared to the normal period (July 15^th), the submerged area of summer maize on July 27th during the flood period accounted for 12.10% of planting area of summer maize in Xun county. By August 8th, this percentage had increased to 19.28%. (3) There were significant differences in the disasters of summer maize among county−level administrative units. The summer maize in Baisi town was the most severely affected by the flood disaster, followed by Xiaohe town. Compared to the flood period on July 27^th, the percentage of increased submerged area in each town to the total increased submerged area of summer maize in Xun county, the percentage of submerged area to the total submerged area of summer maize in Xun county, and the percentage of submerged area in each town to the total planting area of summer maize in Xun county on August 8^th, were found to be relatively high in Baisi town, with the percentage of 54.01%, 52.74%, and 7.37%, respectively. In Xiaohe town, their percentages were 20.45%, 24.01%, and 6.13%, respectively.

Key words: Sentinel?1 SAR Images, Summer Maize, Flood Disaster, Monitoring