An approach for surface soil moisture retrieval using microwave vegetation indices based on SMOS data

An approach for retrieving surface soil moisture using microwave vegetation indices (MVIs) based on SMOS data is presented in this paper. The vegetation optical depth is analytically derived from simplified multi-angular MVIs and the soil dielectric constant to correct the vegetation effect. By minimizing the difference between modeled and observed brightness temperature at six different fixed angles, the only unknown soil moisture can be retrieved. Validations using ground measured soil moisture from Yanco study area in Australia indicated that this new approach improve the accuracy of SMOS L2 soil moisture products, with the RMSE increased from 0.072(m3/m3) to 0.053(m3/m3) and the correlation coefficients increased from 0.690 to 0.696.