Modelling evolution of a large, critical glacier-fed lake in the Western Indian Himalaya

In this study, we simulated the evolution of a large glacier-fed lake called the Gepangath lake located in Western Himalayas by numerically modelling the evolution of the Gepangath glacier that feeds the lake. This modelling was carried out by a 1D model that is based on the principle of mass conservation. The 1D model was forced with the glacier surface mass balance (SMB). Due to non-availability of published in-situ estimates, the SMB was estimated using an energy balance-based model on station derived and reanalysis derived meteorological data. Modelled glacier length fluctuations for over 134 years matched reasonably well with that of observed within the RMSE error ~320 m. In addition to that, between 2004 and 2019, the modelled and observed lake lengths were in agreement with each other with the RMSE ~110 m. Modelled glacier lake lengths also match well with published, satellite imagery derived lengths within 15% uncertainty. The obtained results though not highly accurate but demonstrate the importance of the combination of numerical models viz. ice-flow model and mass balance estimation model along with satellite images in modelling glacier lake evolution in the data-sparse Indian Himalayan Region (IHR). Such studies have the potential to help understand as well as predict the evolution of critical glacier-fed lakes in the IHR.