Changes in soil moisture and vegetation over the Tibetan Plateau during 2000–2019

The Tibetan Plateau (TP), known as the “Water Tower of Asia”, is an ecology-fragile region that is extremely sensitive to climate change. In this paper, the spatio-temporal trends of soil moisture (SM) and vegetation and their response to climatic factors (precipitation and air temperature) were explored by using remotely sensed ESA CCI SM and MODIS LAI data respectively in the growing season during 2000–2019 over the TP. Results show TP is generally wetting and significantly greening during the study period. The significant increasing trend of SM accounts for 21.80% of the TP, which is about twice of its significant decreasing trend (10.19%), while more than half of LAI (58.21 %) display a significant increasing trend. The precipitation is positively correlated with SM in most regions of TP and is the main driving factor of SM change. In contrast, temperature plays a more dominant role than precipitation in vegetation greening over the TP. The combined trend of SM and LAI indicates that TP mainly consists of wetting and greening regions, followed by drying and greening areas.