Large-scale Soil Moisture Mapping on the Tibetan Plateau (TP) Using Bias-corrected ERA5-Land Product

Permafrost on the Tibetan Plateau (TP) has been undergoing degradation as a result of global warming, thus having a profound impact on regional climate, hydrology, and ecological processes. Soil moisture is a key factor of the freeze-thaw processes in permafrost regions. As field observations are often sparsely distributed, it is crucial to understand its variation on a large scale using remote sensing observations and products. In this study, ERA5-Land data in the heartland on the TP are categorized into four vegetation types and bias-corrected by VMD (Variational Mode Decomposition), which are then interpolated into SM distribution maps. The produced ERA5-Land SM distribution data are validated against in-situ observations. The results show that the bias-corrected SM data are consistent with in-situ observations and can be used to depict the soil moisture distribution in an extended region. The result offers a perspective on the soil moisture differences in permafrost across different surface vegetations and provide a basis for future permafrost mapping on the TP.