The Study Of Soil Moisture Retrieval Under Vegetation Coverage Using SAR Data

In this thesis report,the spatial distribution of soil moisture in the Qinghai Lake catchment area is studied using Dubois and water cloud model.The theoretical basis of soil moisture inversion is introduced at the beginning of the paper.The basic situation of the research area “Qinghai Lake catchment” is introduced.The software used in the research is then introduced,as SNAP,Envi Sarscape 5.1 and ArcGIS.Then,the ground measurement is also introduced.The volumetric soil water content at a depth of 5 cm was measured using TDR instrument.Soil roughness was also measured by "manual probe" method.The accurate measurement position is determined by using GPS.And the Radarsat-2 SAR satellite data are obtained synchronously.The water cloud model was used to remove the influence of vegetation.Then,a combination of the water cloud model and Dubois model as well as the vegetation parameters were used to calculate for the parameters of water cloud model in HH and VV polarization.Subsequently,the soil moisture in the Qinghai Lake catchment was calculated by the water cloud model and the Dubois model.Finally,the correlation coefficient between observed and retrieved soil moisture is 0.79,which proves the validity of the method.