Analysis of energy balance and its role in melting over Gangotri and Saraswati glaciated region from 2001–2022

Surface energy balance plays a major role in mass balance and glacier melting. In response to climate change, the influence of radiations and turbulent heat fluxes is a governing factor for glacier melting. In the present study, the energy budget method is used to estimate glacier melting at the grid level using ERA-5 data for Gangotri and Saraswati glaciers in Uttarakhand. Results indicate net radiation dominates the energy budget rather than heat fluxes. Temperature plays a key role in enhancing solar and net radiation, and a strong negative correlation is observed between the snow-covered area and heat fluxes. Turbulent heat fluxes have a strong influence on the snow-covered area of Gangotri, while for Saraswati, the radiations are major contributors. The relationship between snowmelt is directly linked with energy balance and temperature. Although Gangotri receives more energy than Saraswati, the annual average trend shows that Saraswati is showing a rise over the period. Melting is calculated at the grid level for both glaciers when referred to with available snowmelt data, and biases in data are observed. A very strong correlation of 0.99 and 0.96 is observed between calculated melting and available melt for Gangotri and Saraswati glaciers during the ablation months. The total melting calculated at the grid level for the Gangotri glacier region varies from 344.09 to 731.64 mm.w.e. a^–1 and for the Saraswati glacier region, it ranges between 172.11 and 439.68 mm.w.e. a^–1. The 22 years’ average melting rate is 541.17 and 281.75 mm.w.e. a^–1 for Gangotri and Saraswati, respectively, as calculated from 2001 to 2022. Gangotri observes higher melting than Saraswati. Melting calculated in different zones of glacier region varies significantly during the ablation period.