基于MODIS数据的增强型土壤表层水分含量指数模型构造与应用

摘要

土壤水分含量对光谱变化的影响和植被冠层的光谱反射率是干旱最重要和最直接的指标.根据水的吸收率光谱变化特征和绿色植物有效光谱响应特征曲线,在前期提出的地表含水量指数(SWCI)的基础上,增加MO-DIS通道1的红光光谱,以增强植被对光谱吸收的变化反应,可应用于大范围且快速的浅层土壤墒情遥感监测.通过与土壤表层水分含量指数(SWCI)对比分析发现,在对浅层(0～30 cm)土壤水分进行监测时,ESWCI比SWCI更为敏感,这将有助于在实时干旱动态监测中更好地提高监测精度.%Soil moisture and vegetation conditions are the most important and direct indexes in drought monitoring, and the retrieval accuracy is important in the judgment of drought degree. A new model of Enhanced Surface Water Content Index (ESWCI), which adds the channel 1 of MODIS based on the Model of SWCI and the characteristic of chlorophyll spectrum, is put forward. The validation results show that ESWCI is more sensitive for surface water content retrieval than SWCI, and suits for regional drought monitoring, which is conducive to the improvement of the accuracy of soil drought monitoring in real-time.