Empirical and thermal resistance approaches for debris thickness estimation on the Hoksar Glacier, Kashmir Himalaya

Supraglacial debris modulates the thermal regime and alters glacial melt rates depending on its thickness. Thus, the estimation of debris thickness becomes imperative for predicting the hydrological response and dynamics of such glaciers. This study tests the performance of empirical and thermal resistance-based debris thickness approaches against field measurements on the Hoksar Glacier, Kashmir Himalaya. The aim of this study was accomplished using thermal imageries (Landsat 8 Operational Land Imager [Landsat-OLI], 2017 and Advanced Spaceborne Thermal Emission and Reflection Radiometer [ASTER] Surface Kinetic Temperature Product [AST08], 2017) and the European Centre for Medium-Range Weather Forecasts (ECMWF) Reanalysis v5 (ERA-5) datasets. First, the spatially resolved estimates of debris thickness for the entire debris-covered zone were achieved by establishing an empirical relationship between debris thickness and debris surface temperature (both field and satellite thermal imageries). Second, debris thickness for every pixel of thermal imagery was executed by calculating thermal resistance from the energy balance model incorporating primary inputs from (ERA-5), debris temperature (AST08, Landsat OLI), and thermal conductivity. On comparison with field temperature and thickness measurements with satellite temperature, homogenous debris thickness pixels showed an excellent coherence ( r = 0.9; p