Spatiotemporally Heterogeneous Impact of Proglacial Lake on Himalayan Glacier Dynamics Revealed by Multisource Remote Sensing

Proglacial lakes modulate lake-terminating glacier dynamics and can substantially amplify ice loss via frontal calving. While critical for accurate glacier projections, proglacial lake-glacier interactions remain poorly understood across the Himalayas. Here, we apply zonal statistics to investigate spatiotemporal characteristics of proglacial lake impacts on lake-terminating glacier dynamics, by comparing multi-source remote sensing-based surface velocities and surface-elevation-change (thinning) rates of 346 lake-terminating versus 462 land-terminating glaciers (2000–2020). Lake-terminating glaciers exhibit on average 32.39% higher surface velocity and 41.65% greater thinning rate. The strongest velocity impacts occur in the eastern Himalayas (41.62%), northern central Himalayas (51.03%), and Nyainqentanglha (48.76%), while thinning increases are notable in the eastern Hindu Kush, central Himalayas, and Hengduan range. Temporally, proglacial lake influence on velocity intensified nearly linearly from 1990 to 2020 (24.80% to 38.6%), whereas impacts on thinning rates showed a linear declining trend (62.4% to 28.6%) across four five-year intervals from 2000 to 2020. Manual terminus delineation from multi-source satellite imagery (Landsat, Sentinel-2) indicates that, during 2000–2020, 87.6% of lake-terminating glaciers retreated at a mean rate of 10.88±2.40 m yr⁻¹. An interaction index between proglacial lakes and lake-terminating glaciers revealed the strongest interaction in the Nyainqentanglha and Karakoram, followed by intensity zones in adjacent eastern/central Himalayan sectors. Our findings underscore the need for comprehensive observations and modeling to better resolve the processes that govern lake-glacier interactions. This study demonstrates the particular strength of multi-source remote sensing in revealing large-scale glacier–lake interactions.