Quantifying glacier mass balance, proglacial lake water levels, and volume changes through remote sensing is crucial for assessing the response of glaciers and lakes to climate change. Glaciers, as significant solid water reservoirs, play a key role in regional hydrological cycles, especially in arid or semi-arid regions with scarce precipitation. The Tien Shan, one of the largest mountain ranges in global drylands, holds a critical position in regional water resource distribution, with glacier meltwater significantly impacting the sustainable development of surrounding societies, economies, and ecosystems. In the current context of climate change, ongoing glacier retreat has increased the instability of proglacial lakes, posing safety risks to downstream areas. Therefore, studying the long-term changes of Tien Shan glaciers and proglacial lakes is vital for understanding the evolution of glaciers and proglacial lakes, their interaction mechanisms, and assessing the risks of lake outburst floods.
To address this, a team of researchers including Ph.D. student Wang Yingzheng, jointly trained by Lanzhou University and the Institute of Tibetan Plateau Research (ITP), CAS, and researchers Li Xin, Zheng Donghai, Professor Nian Yanyun (Lanzhou University), Associate Professor Zhou Yushan (Central South University), and Professor Tang Zhiguang (Hunan University of Science and Technology), focused on glaciers and proglacial lakes in the Ak-Shyirak region of the central Tien Shan. They used multi-source DEM data (such as KH-9 DEM, SRTM DEM, and ASTER DEM) to quantify glacier thickness changes and mass balance from 1973 to 2023 through a DEM differencing method. Using ICESat-2 laser altimetry and Sentinel-3 radar altimetry data, they quantified intra-annual fluctuations and interannual trends of Petrov Lake from 2019 to 2023, based on a periodic fluctuation model. The study also utilized EAR5-Land reanalysis data to analyze the impact factors of glacier mass balance and proglacial lake water level changes, further quantifying the contributions of glacier meltwater and precipitation to changes in lake water storage.
The results show that over the past 50 years (1973-2013), the annual average glacier area reduction rate in the Ak-Shyirak region was 1.97 km²/year, and the mass balance rate was -0.33 m w.e./year, with varying glacier thinning rates across different periods (see Figure 1). Meanwhile, the area of Petrov Lake increased by 2.78 km² (an increase of 148.51%, see Figure 2). In the past five years, the interannual growth rate of the lake's water level was 0.30 m/year, with an intra-annual fluctuation of 0.67 m (see Figure 3). The volume of the lake increased by 9.39×10⁶ m³. A comprehensive analysis of multiple factors (such as topography, temperature, precipitation, and snowfall) led to the following conclusions: (1) Glacier dynamics, temperature variations, and snowfall are the primary factors influencing glacier mass balance; (2) Basin topography, glacier surface elevation, and anomalous drainage affect the rate and direction of proglacial lake expansion; (3) Glacier meltwater contributed 36.2% to the increase in Petrov Lake volume, while precipitation contributed 63.8%, with only 3.3% of the water directly contributing to lake expansion. The multi-source data and analysis methods used in this study provide important references for future research on the interaction mechanisms between glaciers and proglacial lakes.
This research, titled "Glacier Mass Change and Evolution of Petrov Lake in the Ak-Shyirak Massif, Central Tien Shan, from 1973 to 2023 Using Multisource Satellite Data," was published in the international journalRemote Sensing of Environment. Ph.D. student Wang Yingzheng is the first author, while Researcher Li Xin and Associate Professor Zhou Yushan are co-corresponding authors. This study was funded by the National Key R&D Program of China (Grant No. 2021YFB3900105) and the National Natural Science Foundation of China (Grant Nos. 42001381, 42101406).
Paper and attachments link:https://doi.org/10.1016/j.rse.2024.114437
Data link:https://data.tpdc.ac.cn/zh-hans/data/8bd63fe6-a0c9-4078-9d10-09db5a94e9a5
Figure 1: Glacier Thickness Changes in the Ak-Shyirak Region from 1973 to 2023
Figure 2: Evolution of Petrov Proglacial Lake from 1973 to 2023
Figure 3: Temporal Variation of Petrov Lake Area and Water Level
