基于Sentinel-1A雷达影像阳澄湖凤眼莲遥感动态提取分析

Dynamic extraction and analysis of Yangcheng Lake water hyacinth based on Sentinel-1A radar images

凤眼莲是一种水生大型植被和高度入侵的物种,容易引起一系列生态、经济、社会问题,对其进行有效监测有重要意义。本研究以阳澄湖为研究区域,利用2021年多时相哨兵一号雷达卫星的垂直发射垂直接收(VV)、垂直发射水平接收(VH)极化数据,分析阳澄湖凤眼莲的生长周期内雷达后向散射强度变化特征,进行不同极化模式下基于阈值的凤眼莲提取研究,并验证凤眼莲分布提取结果。结果表明:①微波遥感为监测凤眼莲提供了有效监测手段,利用雷达影像对阳澄湖区域可以有效进行凤眼莲识别提取;②不同极化模式下,凤眼莲的后向散射强度差异明显,且时序差异也比较明显;③相较于VH极化方式,VV极化方式下的凤眼莲雷达散射强度整体更高;④VH极化模式下的凤眼莲提取精度优于VV极化模式,且精度可达到89.5%。

Water hyacinth is a large aquatic vegetation and highly invasive species,which can easily cause a series of ecological,economic and social problems.The effective monitoring of water hyacinth is of great significance.In this study,Yangcheng Lake was used as the research area,and the vertical transmit/vertical receive(VV)and vertical transmit/horizontal receive(VH)polarization data of the multi-phase Sentinel-1A radar satellite in 2021 were applied to analyze the variation characteristics of radar backscattering intensity during the growth cycle of Yangcheng Lake water hyacinth.The threshold-based water hyacinth extraction experiment under different polarization modes was carried out to analyze and verify the extraction results of the water hyacinth distribution.The results showed:1.Microwave remote sensing could provide an effective monitoring method for monitoring the water hyacinth,and the use of radar images could effectively identify and extract the water hyacinth in the Yangcheng Lake area.2.Under different polarization modes,the backscattering intensity of the water hyacinth was obviously different,and the timing difference was also obvious;3.Compared with the VH polarization method,the radar scattering intensity of the water hyacinth under the VV polarization method was generally higher;4.The extraction accuracy of water hyacinth in the VH polarization mode iwas better than that in the VV polarization mode,and the accuracy could reach 89.5%.