Characteristics of Musta Glacier surges and their responses to climate change between 1976 and 2023

Abstract

Understanding the differential responses of various tributaries of the same glacier to climate change under similar climatic conditions in the Karakoram is crucial for unraveling the complexity of glacier dynamics in this region. This study systematically examines the surface elevation, flow velocity, morphological changes, and climate responses for different tributary glaciers of the Musta Glacier, using multi-source remote sensing imagery and meteorological reanalysis data from 1976 to 2023. The findings reveal that the tributaries of Musta Glacier experienced a total of nine surges, with an average duration exceeding ten years. These surges typically began in spring and summer and concluded in summer and autumn. During these events, the glaciers transferred an estimated 1.32 km³ of material downstream, resulting in an average thickening of over 30 m in the receiving area. The analysis of velocities reveals that the acceleration phase of Musta Glacier tributary surges ranges from 1 to 12 years, with an average duration exceeding 6 years, while the deceleration phase consistently lasts less than 4 years. Among the tributaries, the South Chongtar Glacier exhibits the most rapid surge dynamics, with a total surge duration of just 5 years. Additionally, all surging tributaries of Musta Glacier induce notable geomorphic changes during their surge events, including the formation of ring-shaped moraines and terminal advances. Comparative analysis with previous studies reveals that the surge characteristics of most Musta Glacier tributaries resemble those of thermally controlled Svalbard-type surging glaciers. Furthermore, we observed that the surging patterns of Musta Glacier are closely linked to regional climatic variations, characterized by increased precipitation and noticeably cooling prior to surge initiation. On the other hand, we proposed that the asynchronous surging behavior among the tributaries of Musta Glacier is primarily driven by variations in the internal dynamic processes of each glacier in response to climatic changes. In conclusion, our findings provide a quantitative and detailed characterization of the surging processes of Musta Glacier, offering deeper insights into the complexity of glacier surging under changing climatic conditions.