Advancing the understanding for hydro-climatic controls on water balance and lake-level variability in the Tibetan Plateau : Hydrological modeling in data-scarce lake basins integrating multi-source data

The contrasting patterns of lake-level changes across the Tibetan Plateau (TP) are indicators of differences in the water balance over the TP. However, little is known about the key hydrological factors controlling this variability. The purpose of this study was to contribute to a more quantitative understanding of these factors for four selected lakes in the southern-central part of the TP: Nam Co and Tangra Yumco (increasing water levels), and Mapam Yumco and Paiku Co (stable or slightly decreasing water levels). Therefore, an integrated approach combining hydrological modeling, atmospheric-model output and remote-sensing data was developed. The J2000g hydrological model was adapted and extended according to the specific characteristics of closed-lake basins on the TP and driven with High Asia Refined analysis (HAR) data at 10 km resolution for the period 2001–2010. Differences in the mean annual water balances among the four basins are primarily related to higher precipitation totals and attributed runoff generation in the Nam Co and Tangra Yumco basins. Precipitation and associated runoff are the main driving forces for inter-annual lake variations. The glacier-meltwater contribution to the total basin runoff volume (between 14 and 30% averaged over the 10-year period) plays a less important role compared to runoff generation from rainfall and snowmelt in non-glacierized land areas. These results highlight the benefits of linking hydrological modeling with atmospheric-model output and satellite-derived data in regions where observation data are scarce, and the developed approach can be readily transferred to other data-scarce closed-lake basins, opening new directions of research.