Remote sensing monitoring of glacier changes and analysis of climate response on the northern slope of the Western Himalayas from 1990 to 2024

The glaciers on northern slope of the Western Himalayas play an irreplaceable role in maintaining water resource balance in northwestern South Asia, regulating river runoff stability, and providing ecological barrier functions. Under the context of global warming, the accelerated melting of glaciers in this region exhibits significant differences from those in the Eastern and Central Himalayas and has led to hydrological reorganization and disaster risk increases, seriously threatening regional ecological security and social stability. Therefore, there is an urgent need to strengthen the monitoring and research on the dynamics and driving mechanisms of glaciers on the northern slope of the Western Himalayas. Based on Landsat TM/ETM+/OLI series remote sensing, this study uses the ratio threshold method to extract glacier boundaries for different periods on northern slope of the Western Himalayas from 1990 to 2024, systematically analyzing the temporal and spatial characteristics of glacier changes and their influencing factors. Results are as follows: (1) The study area glaciers exhibit a pronounced and accelerating retreat trend, with an average annual retreat rate of 0.65%/a during the study period. (2) Glacier area increases with elevation and then decreases, showing a unimodal pattern. The most pronounced glacier retreat occurs between 5400 and 5600 m. Mid-slope regions with gradients of 25°–30° represent the primary zones of glacier recession. (3) Some glaciers in study area are covered by supraglacial debris, and the debris-covered glaciers (accounting for 18.6% of the total glacier area) exhibit greater stability. This indicates that supraglacial debris can, to some extent, suppress glacier ablation in the study area. Valley glaciers are widely distributed, and the elevation at which glaciers develop is a key factor influencing the rate of area change among different glacier types. (4) Based on the analysis of glacier–climate responses with a 10-year lag, rising air temperature (0.015°C/a) and decreasing precipitation (−7.04 mm/a) are the primary climatic drivers of accelerated glacier retreat in the study area. Among these factors, anomalously high summer temperatures and the substantial reduction in solid precipitation exert particularly pronounced impacts on glacier ablation. This study reveals the temporal and spatial changes of glaciers on northern slope of the Western Himalayas and their climate-driven mechanisms, aiming to provide a scientific basis for adaptive management strategies and to enhance the security of regional water resources.