Quantifying glacier mass change and its contribution to lake growths in central Kunlun during 2000-2015 from multi-source remote sensing data

Joint monitoring of the variations of glaciers and lakes within a basin is essential for an accurate understanding of region-wide climate change and the water cycle process. The central Kunlun-KekeXili region is an ideal experimental field due to the wide distribution of glaciers and lakes. In this study, we first investigated the glacier mass balance of 2000-2015/16 for seven major glacier clusters by utilizing high-resolution SPOT-6/7 stereo imagery and the SRTM DEM. The final results revealed an overall mass balance of - 0.16 +/- 0.05 m w.e./a. for the study region (with a total glacier area of 967 km(2)). Secondly, ICESat/GLAS altimetry data were used to quantify the water-level change of 2003-2008/09 for the two largest glacier-fed closed lakes (i.e., LexieWudan Lake and KekeXili Lake) in this region. Based on this, we applied a strategy which establishes the statistical relationship between the lake area change and the lake water-level change for 2003-2008/09 to estimate the specific water level using the corresponding lake area. We then further calculated the variation in lake water storage between 2000 and 2015. The results showed that the water storage of LexieWudan Lake and KekeXili Lake increased by 1.82 +/- 0.14 km(3) and 1.90 +/- 0.38 km(3), respectively. For each lake basin, meanwhile, the glaciers lost - 0.18 +/- 0.03 km(3) and - 0.21 +/- 0.04 km(3) of water, accounting for 9.9% and 11.1% of the increase in lake water storage for LexieWudan Lake and KekeXili Lake, respectively. Our results not only demonstrate that glacier meltwater has only a limited impact on the lake expansion in this region, but they also provide new evidence for the warming and wetting process of the climate in the northern part of the Qinghai-Tibet Plateau.