基于MODIS数据的新疆地区土壤湿度反演

以新疆地区为研究对象,选取2016年5和6月的植被指数产品数据和地表温度产品数据,构建新疆地区NDVI-Ts和EVI-Ts特征空间,分析新疆地区土壤干湿状况的空间分布格局及土壤水分的影响因素。结合野外同步重复采样获得的土壤含水量对TVDI进行验证,并分析EVI和Ts所包含的旱情信息。结果表明:(1)构建NDVI-Ts和EVI-Ts特征空间,其散点图符合三角形的关系。(2)新疆地区5和6月土壤湿度总体以干旱(0.6

Retrieval of soil moisture information in Xinjiang using MODIS

MOD13A2,MOD11A2 and field measurements were utilized to study soil moisture variation in Xinjiang during May and June.Relationships between NDVI (Normalized Difference Vegetation Index) and Ts (Land Surface Temperature),and EVI (Enhanced Vegetation Index) and Ts were investigated.The spatial pattern of the temperature vegetation dryness index (TVDI) and influencing factors were analyzed.Results:(1) NDVI-Ts and EVI-Ts follow the classic triangle relationship.(2) Soil moisture in Xinjiang was mainly dominated by drought conditions (0.6＜TVDI＜0.8);Spatially,Alta,the middle slope area of the Tianshan Mountains,and the south slopes of the Kunlun Mountains are characterized by extremely wet conditions,while the north Junggar basin and southern Tarim Basin are dry.(3) The TVDI of forested land was lowest in May while the TVDI of grassland was lowest in June;soil moisture generally increased with elevation.(4) For regions with high vegetation coverage,EVI based TVDI is more suitable than NDVI based TVDI for drought monitoring.(5) The land surface temperature was better able to reflect drought conditions compared to vegetation index.