Study Of Retrieving Soil Moisture Based On SAR Data

Soil moisture is one of the key parameter to control earth surface processes,and accurate monitoring is always a hot issue in the quantitative remote sensing research.Currently,soil moisture content from traditional methods such as visible,near Infrared,thermal infrared light and vegetation index are not detected directly and tend to be affected by the weather with poor spatiotemporal contrast and low resolution.In contrast,soil moisture from microwave remote sensing is characterized by high resolution,Clear physical meaning and being unaffected by the weather.Using Sentinel-1 SAR data with the resolution of 10 m from ESA,the study retrieved soil moisture content in the typical steppe of Inner Mongolia and verified the accuracy by measured data,analyzed the feasibility study of monitoring drought in study region was conducted.The results will provide theoretical and methodological support for soil moisture monitoring and drought assessment in grassland.The results are as follows:1.Backscatter coefficient was significantly and positively correlated with soil moisture and sensitive to its changes.Therefore,it is suitable to monitor soil moisture in the typical steppe.2.There was not obvious change of backscatter coefficient calculated by watercloud model based on measured soil moisture of vegetation canopy,which indicated that backscatter coefficient extracted by Sentinel-1SAR can retrieve soil moisture in the typical steppe.3.Being not significant spatial relationship between soil moisture and VCI indicated that the absolute value of soil moisture failed to reflect vegetation conditions and backscatter coefficient was not used directly to reflect drought.The soil moisture threshold of drought should be set among different grasslands and then drought is reflected by soil water deficit?...