Evaluation of Multiple Satellite-Based Soil Moisture Products over Continental U.S. Based on In Situ Measurements

Measurements of soil water content are of great importance for climatic researches and hydrological applications. Satellite remote sensing techniques have provided convenient access to global soil moisture data at high temporal resolution. The evaluation of remotely sensed soil moisture products from multiple sensors are fundamental for understanding the quality and usefulness of the products and are helpful for the improvements of the retrieval algorithms. In this study, we evaluated four satellite-based soil moisture products against two in situ networks over continental U.S. These products are the Soil Moisture and Ocean Salinity (SMOS), the Advanced Microwave Scanning Radiometer for the Earth observing system (AMSR-E), the Fengyun-3B/Microwave Radiation Imager (FY-3B/MWRI), and the Essential Climate Variable (ECV) soil moisture products. The evaluation results show that the temporal characteristics of ECV and SMOS soil moisture products are consistent with those of in situ measurements. Larger errors and bias exist in AMSR-E and FY-3B/MWRI over the study region. In general, the ECV product performs the best comparing with other products. Therefore, the ECV product is recommended in regional hydrological applications and water resource management over the continental U.S. for its good performance in absolute values and soil moisture anomalies.