Applicability of remote sensing inversion models for estimating regional soil moisture in Chinese grasslands

Using MODIS data, three soil moisture inversion models (ATI, TVDI, and VSWI) of Chinese grasslands were constructed, and the output of the three models was verified using measured soil moisture data and AMSR2 data to assess the models’ applicability. The inversion results of the three models were correlated with measured soil moisture to varying degrees, which may reflect spatial and temporal variation of soil moisture in the entire region. The ATI model was considered suitable for estimating soil moisture inversion in grass ecosystems, meadow ecosystems, and in alpine sparse vegetation and tundra ecosystems in winter; however, it produced high error rates regarding summer soil moisture inversion. Furthermore, this model was considered unsuitable for soil moisture inversion of grassland ecosystems. The TVDI model showed good applicability regarding grass ecosystems, meadow ecosystems, and in alpine sparse vegetation and tundra ecosystems in spring, but it produced considerable deviation in winter. The VSWI model showed low error rates in summer, and it was considered suitable for soil moisture inversion of grassland ecosystems.