Exploring the water storage changes in the largest lake (Selin Co) over the Tibetan Plateau during 2003-2012 from a basin-wide hydrological modeling

Lake water storage change (Delta S-w) is an important indicator of the hydrologic cycle and greatly influences lake expansion/shrinkage over the Tibetan Plateau (TP). Accurate estimation of Delta S-w will contribute to improved understanding of lake variations in the TP. Based on a water balance, this study explored the variations of Delta S-w for the Lake Selin Co (the largest closed lake on the TP) during 2003-2012 using the Water and Energy Budget-based Distributed Hydrological Model (WEB-DHM) together with two different evapotranspiration (ET) algorithms (the Penman-Monteith method and a simple sublimation estimation approach for water area in unfrozen and frozen period). The contributions of basin discharge and climate causes to the Delta S-w are also quantitatively analyzed. The results showed that WEB-DHM could well reproduce daily discharge, the spatial pattern, and basin-averaged values of MODIS land surface temperature (LST) during nighttime and daytime. Compared with the ET reference values estimated from the basin-wide water balance, our ET estimates showed better performance than three global ET products in reproducing basin-averaged ET. The modeled ET at point scale matches well with short-term in situ daily measurements (RMSE = 0.82 mm/d). Lake inflows and precipitation over the water area had stronger relationships with Delta S-w in the warm season and monthly scale, whereas evaporation from the water area had remarkable effects on Delta S-w in the cold season. The total contribution of the three factors to Delta S-w was about 90%, and accounting for 49.5%, 22.1%, and 18.3%, respectively.