基于HJ卫星数据的土壤含水量反演及其旱情预测

Retrieval of soil moisture by HJ Image and prediction of drought

干旱是影响中国农业生产的重要自然灾害之一。为确定温度植被干旱指数(TVDI)法在苏北地区干旱监测中的适用性,本试验构建基于HJ卫星数据的NDVI-Ts特征空间,提取TVDI并结合实测数据将遥感指数转化为土壤相对湿度。结果显示:特征空间构建时,考虑NDVI>0.2区间可提高干、湿边的拟合精度;TVDI与各层土壤含水量均有一定的相关性,其中与10~20 cm土层土壤含水量的相关系数达-0.649^-0.854(P<0.01)。结合同期降水数据,可认为基于HJ卫星数据的TVDI法对苏北地区旱情具有较好的监测效果。

Drought is one kind of natural disasters that seriously affect agricultural production in China. In order to determine the feasibility of temperature vegetation dryness index （ TVDI ） used in drought monitoring in north of Jiangsu province, NDVI-Ts feature space was constructed by using HJ satellite data, temperature vegetation dryness index was ex-tracted and the remote sensing index combining the measured data was turned into relative soil moisture. The results showed that improving NDVI to be more than 0. 2 could improve the dry and wet edge fitting accuracy when constructing the feature space. TVDI index was correlated with soil moisture in different depths, and the coefficients between TVDI and soil mois-ture in the depth of 10-20 cm was from-0. 649 to-0. 854. Combined with contempory rainfall data, TVDI was applicable in drought prediction.