A New Method to Retrieve Soil Moisture at Bare Soil Surface Using ERS Scatterometer Data

ERS wind scatterometer provides capability of the multiple angles by their three different look antennas, In this study, we evaluate whether the multi-incidence angle observations can help on improving surface soil moisture estimations. With the theoretical surface backscattering model - the advanced integral equation Model (AIEM), we first simulated a surface backscattering database with a wide range of surface roughness and soil moisture properties at different incident angles. Then, a parameterized surface backscattering model is developed using the simulated database. The newly developed simple model has the roughness function that can be described by a single combined roughness parameter from the commonly used surface roughness descriptors (RMS height and correlation length). This makes it possible to be used as an inversion model. We will demonstrate this simple model development, its accuracy, and inversion test by using the ground measurements from the Intensive Observation Period (IOP'98) field campaign in 1998 of the Global Energy and Water Experiment (GEWEX) Asian Monsoon Experiment Tibet (GAME/Tibet).