Glacier Mass Balance Pattern and Its Variation Mechanism in the West Kunlun Mountains in Tibetan Plateau

Abstract

Mass balance observations are beneficial for assessing climate change in different world regions. This study analyzed the glacier elevation change, ice flux divergence, and surface mass balance (SMB) in the West Kunlun Mountains (WKM) on the Tibetan Plateau using remote sensing data, including satellite altimetry, glacier surface velocity, and thickness fields. Seventeen local glaciers were examined in detail and showed varying surface elevation changes from −0.39 ± 0.11 to 0.83 ± 0.10 m/a. Overall, we obtained a reasonably rapid elevation trend of 0.21 ± 0.14 m/a. By combining the ice flux divergence and surface mass balance, the overall thickness change of the WKM glacier over time is almost zero, and the WKM glacier shows a positive mass balance of 0.21 ± 0.98 m/a. Moreover, the ice flux divergence is more significant on the ice tongue than in the flat region due to the more considerable gradient of surface velocity and thickness fields. We found that glacier heterogeneity dynamics were associated with a surging dynamic mechanism concentrated in the glacier tongue and were induced by inner terrain instabilities. The glacier surging causes a drastic drop in glacier elevation but does not cause a glacier mass gain or loss, and it has an enhanced effect on the ice flux divergence. Therefore, glacier surging is the main reason for the decline of the two glaciers monitored. In addition, the long-term meteorological data analysis found that, since 2000, the air temperature warming hiatus may have balanced the three glaciers, and significantly increasing precipitation variation may cause the glacier to thicken the most.