Research On The Soil Water Retrieval Based On The MODIS Data In Shanxi Province

Soil moisture is an important indicator for monitoring soil degradation. It has devastating impacts on agriculture、water resources、 economy and environment. It plays an important role on the water and energy exchange at the land surface/atmosphere interface. So it is significant to do research on how to monitor soil moisture by remote sensing, which can provide information on large area quickly and easily, and according to the existing soil moisture measured data, we can do some simulation and Estimation test to conduct further soil moisture retrieval.After analyze all kinds of information about soil moisture reversion and compare different quantitative remote sensing models, elect to meet a large range of surface soil water content, the key model parameters can be directly obtained image data and other basic conditions, suitable for a large coverage area in Shanxi province and to meet the requirements of the high temporal resolution TVDI and Ts/NDVI model for estimating soil moisture content.Based on MODIS surface temperature and vegetation index products from2008, this article not only uses TVDI model to describe and analyze the wet side of the Ts-NDVI characteristics of space, but also use normalized difference vegetation index (NDVI) and the surface temperature to build the TS-NDVI features of space to do the inversion of soil moisture of Shanxi Province from March to October. Then it uses the method of the Ts/NDVI slope to do the inversion of soil moisture of Shanxi Province, and studys and analyzes the quantitative relationship between the Ts/NDVI and soil measured data to obtain relative soil water content in Shanxi Province from March to October. At the end, it also does the temporal and spatial analysis of inversion results. The main results are as follows:(1) In the case of different surface temperature, there is a positive correlation between the vegetation index and soil moisture. In the case of different vegetation index,there is a negative correlation between surface temperature and soil moisture:if0.15≤NDVI≤0.75, there is a significant negative correlation between surface temperature and soil moisture,while the NDVI value is too large or too small (NDVI <0.15or NDVI>0.75), the relationship was no longer significant. (2) Use TVDI model inversion of soil moisture information can objectively reflect the distribution of soil moisture in Shanxi, show that TVDI can reflect the surface soil moisture conditions.(3) There is a deviation range of2%-13%between the average soil moisture of Shanxi based on Ts/NDVI feature space inversion and the actual value. The Average relative error between them is11.88%.