摘要:
为了方便快捷地得到大范围的土壤含水量产品,以MODIS数据为数据源,淮河流域为研究区域,结合表观热惯量模型和植被供水指数模型的适用性特点,根据地表植被覆盖度的不同,建立综合干旱指数(comprehensive drought index,CDI)模型,对土壤含水量进行反演;然后,将反演的CDI结果与地表实测数据进行相关性建模,得到CDI与实测数据间的最佳拟合模型,利用该模型把CDI结果转化为最终的土壤含水量值;最后,通过实测含水量数据来验证反演结果的可靠性和精度.结果表明,反演得到的土壤含水量与实测土壤含水量相关性较高,相关系数R2均在0.7左右,该方法对于高效地获取大面积土壤含水量信息具有较好的应用价值.
Abstract:
In this study,the authors examined the estimation of soil moisture with various drought indices in Huihe River Basin of East China. MODIS data were used for the estimation. Such drought indices as apparent thermal inertia (ATI) and vegetation supply water index (VSWI) were used for the estimation. On the basis of these drought indices,the authors integrated the drought indices into a comprehensive drought index(CDI) for the study to estimate soil moisture in East China. As dimensionless data,CDI cannot represent the actual soil moisture. The authors introduced the measured data, and built the correlation model between CDI and measured data. CDI can therefore be converted to soil moisture through the model. Finally,the authors used the measured data to verify the reliability and accuracy of the estimation results. The results show that the correlation between measured data and estimation data is high, and R2values are around 0.7. The method in this study has great application value for estimating soil moisture in large area.
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