A method for retrieving high-resolution surface soil moisture by downscaling AMSR-E brightness temperature

This paper presents a method to retrieve surface soil moisture at high-resolution from brightness temperature. To obtain high resolution brightness temperature, downscaling brightness temperature uses higher resolution visible/infrared satellite data and is based on the method of retrieving land surface temperature with passive microwave and the relationship between Microwave Polarization Difference Index (MPDI) and NDVL High resolution soil moisture is retrieved with downscaled brightness temperature using a single-channel algorithm (SCA), and the Q_p model used to deal with the influence of roughness. Downscaled brightness temperature is compared with the aircraft data during the Experiment in the Heihe River Basin in China. The retrieved high resolution soil moisture is compared with in situ (0-6 cm depth) point measurements during SMEX02, obtaining R² = 0.74 and RMSE as 0.047 cm³ cm^-3.