Tirthankar Ghosh: Controls on Himalayan glacier thermal regimes revealed through ensemble thermomechanical modelling
Glacier thermal regimes fundamentally control ice dynamics by influencing englacial and basal hydrology, basal sliding, and ice rheology. They are governed by the interplay between climate, glacier geometry, and ice flow, and are therefore critical for predicting how glaciers will respond to climate change. However, glacier thermal regimes remain poorly characterized globally, particularly for mountain glaciers in the Himalaya. Here, we present results from an ensemble of higher-order thermomechanical simulations of glaciers in the Zanskar Basin of the western Himalaya using the Ice-sheet and Sea-level System Model (ISSM). We systematically evaluate the controls on present-day glacier thermal regimes and explore the uncertainty space in key boundary conditions, including geothermal heat flow, ice rheology parameters by conducting a series of sensitivity experiments. By assessing the response of glacier thermal regimes to these uncertainties, we identify the dominant controls governing their present-day thermal state and evaluate the robustness of thermomechanical model predictions. Our modeling framework provides new insights into the coupled interactions between glacier thermal structure, climate, and ice dynamics. These results contribute to improving process-based understanding of mountain glacier behaviour and represent an important step toward more reliable predictions of glacier change
under a warming climate. This study will be of interest to glaciologists and researchers investigating glacier and ice sheet dynamics, subglacial hydrology, and climate-driven changes in glacierised environments.