A Land Surface Water Deficit Model for an Arid and Semiarid Region: Impact of Desertification on the Water Deficit Status in the Loess Plateau, China

A land surface water deficit model was developed for a large-scale heterogeneous arid and semiarid area with various soil, vegetation, and land use types, and used to simulate seasonal and spatial variability in potential (E0) and actual (Ea) evapotranspiration and an index of water deficit (WDI). Comparisons with the results of other commonly used models and natural vegetation conditions suggest that this model can give an estimate of the success for large-scale regional studies. By using the model, the authors estimated E0, Ea, and WDI in a grid cell of 0.25° lat × 0.25° long over the Loess Plateau, China. Finally, the sensitivities of the model to both a vegetation parameter and an assumed desertification case were simulated, and several highly sensitive areas were found to be the risk regions to desertification.