Modeling of Lake Water Storage Changes in the Tibetan Plateau Using a Land Surface Model Coupled with a Glacier-Melt Scheme

Abstract:

There are more than 1000 lakes with area over 1 km² distributed in the Tibetan plateau (TP). Lakes are key indicators of climate change in the TP. Siling Co is currently the largest closed lake in the central TP with a lake surface area of about 2200 km² and watershed area of about 45 000 km². It is reported that the lake surface area has expanded by about 42% from 1972 to 2011. Studies suggest that the surface extents of Siling Co are likely to reflect an increased contribution to the lake’s water balance of glacier melting, as well as the associated increasing precipitation and decreasing evapotranspiration. A hydrologic model combined with a glacier melt scheme can serve as a valuable tool to quantify the contribution of glacier melt water to the lake storage changes. In this study, we establish a hydrologic modeling framework by coupling the Variable Infiltration Capacity (VIC) distributed land surface hydrological model with an energy-balance based glacier-melt model over the Siling Co basin. The contributions from precipitation, glacier melting and evapotranspiration to the water balance of Siling Co are quantified via the model simulations during 1971-2013. This work aims to quantitatively analyze the main causes for the Siling Co growth during recent decades, and better understand the hydrologic response of closed lakes to climate changes in the TP.