Evaluation of vegetation indices based on microwave data by simulation and measurements

As an indicator of vegetation, vegetation index, such as Microwave Polarization Difference Temperatures (MPDT), Microwave Polarization Difference Index (MPDI) and Microwave Vegetation Indices (MVIs), is widely used in vegetation water content (VWC) and soil moisture retrieval. In this essay, Ferrazzoli's radiative transfer model was utilized for simulation, and a truck-mounted Microwave Radiometer (BNU-TMMR) for experiments. Subsequently, there comes a comparison and evaluation of the three vegetation indices' sensitivity to soil moisture and VWC which were proposed by both utilizing model simulation and field measurements. MPDT and MPDI increase with soil moisture rising up, and are more sensitive to lower soil moisture, while the trend of MVIs_B is smooth. In term of VWC influence, MVIs_B has higher sensitivity to lower VWC vegetation, and they are all negatively correlated to VWC.