Monitoring Glacier Lake Outburst Flood (GLOF) of Lake Merzbacher Using Dense Chinese High-Resolution Satellite Images

Abstract

Establishing an effective real-time monitoring and early warning system for glacier lake outburst floods (GLOFs) requires a full understanding of their occurrence mechanism. However, the harsh conditions and hard-to-reach locations of these glacial lakes limit detailed fieldwork, making satellite imagery a critical tool for monitoring. Lake Mercbacher, an ice-dammed lake in the central Tian Shan mountain range, poses a significant threat downstream due to its relatively high frequency of outbursts. In this study, we first monitored the daily changes in the lake area before the 2022 Lake Mercbacher outburst. Additionally, based on historical satellite images from 2014 to 2021, we calculated the maximum lake area (MLA) and its changes before the outburst. Furthermore, we extracted the proportion of floating ice and water area during the period. The results show that the lake area of Lake Mercbacher would first increase at a relatively low speed (0.01 km2/day) for about one month, followed by a relatively high-speed increase (0.04 km2/day) until reaching the maximum, which would last for about twenty days. Then, the lake area would decrease slowly until the outburst, which would last five days and is significant for early warning. Moreover, the floating ice and water proportion provides more information about the outburst signals. In 2022, we found that the floating ice area increased rapidly during the early warning stage, especially one day before the outburst, accounting for about 50% of the total lake area. Historical evidence indicates that the MLA shows a decreasing trend, and combining it with the outburst date and climate data, we found that the outburst date shows an obvious advance trend (6 days per decade) since 1902, caused by climate warming. Earlier melting results in an earlier outburst. This study provides essential references for monitoring Lake Mercbacher GLOFs and building an effective early warning system.

Spatio-Temporal Distribution Characteristics of Glacial Lakes in the Altai Mountains with Climate Change from 2000 to 2020

“…Glacier retreat provides ample water supply and space for subsequent glacial lake expansion, leading to rapid increases in the number and surface area of glacial lakes [59,60]. From 2000 to 2020, our analysis of data from the glacier catalog and manual visual interpretation revealed an average annual increase in the glacier area in the Altai Mountains region of 21.01%, and glacier numbers declined at an average rate of 1405.15 annually.…”

Three decades of glacial lake research: a bibliometric and visual analysis of glacial lake identification

“…By considering factors such as climate change, glacier dynamics, hydrological processes, and human activities, researchers can better comprehend the driving factors and impacts of glacial lake formation and changes (Prakash and Nagarajan, 2018). Moreover, interdisciplinary approaches aid in the development of early warning systems for GLOFs and decision support tools, contributing to the improved management and protection of these fragile ecosystems (Gu et al, 2023).…”