Soil Moisture Variations Monitoring Using New Microwave Soil Moisture Index (MSMI)

In this study, we will establish our new passive microwave soil moisture index (MSMI) based on data from the Advanced Microwave Scanning Radiometer (AMSR-E) on the Aqua satellite. The theoretical basis of MSMI is the brightness temperature (TB) difference between the ascending across and descending across. To demonstrate the potential of the new microwave soil moisture index, we compared MSMI with the soil moisture (SM) product of NASA. The major purpose of this paper is to describe the concept and techniques involved in the newly developed MSMI and explore the general relationships between MSMI and soil moisture. In this first investigation, the information content of soil moisture and MSMI, was compared by examining its response in variations in the space-time domain. The results indicate that the MSMI can provide significant new information since the microwave measurements are sensitive to the soil moisture change between daytime and night. When soil moisture is higher, the MSMI is lower, when soil moisture content is lower, the MSMI is higher. MSMI will provide a new way in droughts monitoring and flood monitoring.