Quantifying glacier surging and associated lake dynamics in Amu Darya river basin using UAV and remote sensing data

Glaciers in the Pamir region are experiencing rapid melting and receding due to climate change, which has a significant implication for the Amu Darya river basin. Predominantly, surging glaciers, which undergo unpredictable advances, are potentially leading to the obstruction of high-altitude river channels and also glacial lake outburst floods. This study investigates surging glaciers in the Pamir region, specifically focusing on the Medvezhiy (M) and Russian Geographical Society (RGS) glaciers, using long-term reanalysis data records, unmanned aerial vehicles (UAVs), and satellite data during the last decades. Significant changes in regional climate were identified, including increasing precipitation rates (13.3 mm/year) and land surface temperature (0.1°C/decade). Between 1991 to 2023, the RGS glacier experienced a significant advancement around 1448.3 ± 30.0 m, while the Medvezhiy glacier showed a decrease of −703.5 ± 30.0 m. There is a substantial increase in the number (from 19 to 75) and area (from 4889.7 ± 0.6 m 2 to 15345.5 ± 0.6 m 2 ) of RGS lakes along with supra-glacier ponds based on a comparison of ArcGIS base map in 2011 and high-resolution UAV data in 2023. For M glacier, number of lakes increased from 4 to 22 but the lake area declined from 10715.2 ± 0.6 to 365.6 ± 0.6 m 2 . It was noted that the largest lake in 2011 with an area of 10406.4 ± 0.6 m 2 at the southeastern portion of the glacier was not observed in 2023 due to outburst. Both the glaciers have substantially impacted the river flow (Abdukahor river) by obstructing a significant proportion of river channel in recent years and might cause outburst floods. These findings enhance the understanding of glacier dynamics and their impacts on the surrounding areas, emphasizing the urgent need for continued monitoring and appropriate management strategies, with a specific focus on surging glaciers and the associated risks.