基于温度植被干旱指数的华东地区AMSR-E土壤水分数据的空间降尺度研究

土壤水分一直是土壤学领域中较为活跃的研究内容,是陆面过程与水循环的重要影响因素。以AMSR-E为代表的被动微波遥感技术的发展为土壤水分的研究提供了方便,但是其粗糙的空间分辨率限制了其在中小尺度内的应用。因此,本研究利用MODIS温度产品MOD11A2和归一化植被指数产品MOD13A3构建了月时间尺度下的温度植被干旱指数(TVDI);其次,利用温度植被干旱指数TVDI和土壤水分之间的线性负相关关系,对AMSR-E三级土壤水分反演产品进行空间降尺度研究,获取2003年连续月时间尺度下空间分辨率为1 km的土壤水分反演结果,并利用地面实测土壤水分数据对反演结果进行验证。地面实测土壤水分值与降尺度反演结果显著相关,每月的线性相关决定系数均在0.8以上,表明降尺度后的土壤水分反演结果具有较高的精度,能够用来表示土壤水分的分布特征。

Downscaling AMSR-E soil moisture data based on temperature vegetation drought index in Eastern China

Soil moisture is not only an important factor in water cycle and land surface process, but also hot topic in soil science research. As a representative of passive microwave remote sensing technology, AMSR-E provides an avenue for soil moisture study. It is, however, restricted by the small and medium scales involved. Therefore, MOD11A2 and MOD13A3 were used to build the temperature vegetation drought index (TVDI) at a monthly time scale, the linear negative relationship between TVDI and soil moisture was then employed to downscale the spatial resolution of AMSR-E. This final objective was to obtain soil moisture at a spatial resolution of 1 km for each month in 2003. The results were well validated by the ground measured soil moisture data. Decision coefficients in all months were above 0.8. It indicated that the soil moisture results by downscaling were accurate enough and it could be used to characterize spatial distribution of soil moisture.