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

Abstract:

Lake water storage changes (ΔS_w) is an important indicator of the hydrologic cycle and greatly influences lake expansion/shrinkage over the Tibetan Plateau (TP). Accurate estimation of ΔS_w will contribute to an improved understanding of lake variations in the TP. Based on water balance, this study explored the variations of ΔS_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 ΔS_w are also quantitatively analyzed. The result shows that WEB-DHM can well reproduce daily discharges at two gauges. Both daytime and nighttime land surface temperature (LST) simulated by the WEB-DHM agreed well with MODIS LST for both basin-averaged values and spatial patterns. Compared with the ET reference values estimated from the basin-wide water balance, ET estimates in this study 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. Lake inflows and precipitation over the water area had stronger relationships with ΔS_w in warm season and monthly scale, whereas ET from the water area had remarkable effects on ΔS_w in cold season. The above three factors contributed about 87% of the total changes of ΔS_w during 2003-2012.