In-situ measurements reveal drastic intra-regional differences in glacier ablation in Ladakh

In the present study, we report pronounced intraregional disparities in glacier ablation between the Pensilungpa and Rulung glaciers located in western and eastern Ladakh, respectively, as evidenced by in-situ measurements conducted during 2023–2024. The Pensilungpa glacier exhibited the point ablation ranging significantly from –0.50 to –2.93 m w.e. a-1, demonstrating substantial ablation variability. In contrast, the Rulung glacier’s point ablation values range narrowly from –0.81 to –1.34 m w.e. a-1, indicating uniformity. The ablation area-wide mass balances were -1.08 ±0.28 and -0.70 ±0.18 for Pensilungpa and Rulung, respectively. A comparative analysis reveals that Pensilungpa’s ablation-area-wide mass balance was 53.5% higher than that of Rulung glacier. This significant disparity is largely attributable to the distinct altitudinal profiles of the Pensilungpa (4649–5858 m above sea level (asl)), and Rulung (5693–6232 m asl) in conjunction with variable snow inputs. Furthermore, despite the presence of substantial debris on the Pensilungpa, which typically insulates and mitigates ablation, our observations suggest that the higher temperatures at lower altitudes override the debris’s insulating effects. These complex ablation patterns underscore the need for comprehensive evolutionary studies to ensure effective water resource management in the already water-stressed region of Ladakh.