Evaluation of AMSR-E Derived Soil Moisture over Northern China

In this study, the authors evaluated two remotely sensed surface soil moisture datasets derived from the Advanced Microwave Scanning Radiometer of the Earth Observing System （AMSR-E） over northern China. The soil moisture datasets were derived from algorithms developed by the National Snow and Ice Data Center （NSIDC） and jointly developed by the Vrije Universiteit Amsterdam and NASA Goddard Space Flight Center （VUA-NASA）. The NSIDC and VUA-NASA products were compared to in situ soil moisture data from nine enhanced coordinated observation stations. The VUANASA dataset presented a strong correlation with top layer in situ soil moisture observations, and the correlation coefficients ranged from 0.34 to 0.73 （p〈0.01）. The correlation coefficients decreased as the observed soil layer depth increased. The correlation coefficients between the NSIDC retrievals and the top layer in situ observations were between -0.10 and 0.62 （p〈0.01）. Furthermore, VUA-NASA soil moisture variations agreed well with in situ soil moisture dynamics and responded sensitively to precipitation events. In contrast, the NSIDC dataset failed to capture signals of soil moisture dynamics. The analyses demonstrated that the VUA-NASA product was capable of representing soil moisture conditions over northern China.