Estimation of surface soil moisture using FengYun-2E (FY-2E) data: A case study over the source area of the Yellow River

Surface soil moisture (SSM) is a significant variable in various fields of science. This paper aims to analyze and improve a SSM retrieval model to apply it to estimate SSM at the regional scale. Firstly, the model parameters were been analyzed. The rotation angle was transformed into exponential form and the ellipse center horizontal coordinate was decreased for the improved SSM retrieval model. After validation with the simulated data from Common Land Model (CoLM), the result indicated that the accuracy of improved model was not lower than the original one after one model coefficient removed. Subsequently, regional SSM was mapped with improved model from FengYun-2E (FY-2E) observation. In addition, the improved SSM retrieval model showed a good consistency with Climate Change Initiative soil moisture (CCI SM) product. Ultimately, a preliminary validation was conducted using the ground measurements in the source area of the Yellow River (SAYR). The result presented an R of 0.53, a RMSE of 0.06 m 3 /m 3 and a bias of 0.03 m 3 /m 3 .