AUTHOR=Srivastava Smriti , Azam Mohd. Farooq 

TITLE=Mass- and Energy-Balance Modeling and Sublimation Losses on Dokriani Bamak and Chhota Shigri Glaciers in Himalaya Since 1979

JOURNAL=Frontiers in Water

VOLUME=4

YEAR=2022

URL=https://www.frontiersin.org/journals/water/articles/10.3389/frwa.2022.874240

DOI=10.3389/frwa.2022.874240

ISSN=2624-9375

ABSTRACT=<p>Available surface energy balance (SEB) studies on the Himalayan glaciers generally investigate the melt-governing energy fluxes at a point-scale. Further, the annual glacier-wide mass balance (<italic>B</italic><sub><italic>a</italic></sub>) reconstructions have often been performed using temperature-index (T-index) models. In the present study, a mass- and energy-balance model is used to simulate the <italic>B</italic><sub><italic>a</italic></sub> on Dokriani Bamak Glacier (DBG, central Himalaya) and Chhota Shigri Glacier (CSG, western Himalaya) using the bias-corrected ERA5 data from 1979 to 2020. The model is calibrated using <italic>in-situ B</italic><sub><italic>a</italic></sub> and validated against available <italic>in-situ</italic> altitudinal and geodetic mass balances. DBG and CSG show mean <italic>B</italic><sub><italic>a</italic></sub> of −0.27 ± 0.32 and −0.31 ± 0.38 m w.e. a<sup>−1</sup> (meter water equivalent per year), respectively, from 1979 to 2020. Glacier-wide net shortwave radiation dominates the SEB followed by longwave net radiation, latent heat flux, and sensible heat flux. The losses through sublimation are around 22% on DBG and 20% on CSG to the total ablation with a strong spatial and temporal variability. Modeled <italic>B</italic><sub><italic>a</italic></sub> is highly sensitive to snow albedo —with sensitivities of 0.29 and 0.37 m w.e. a<sup>−1</sup> for 10% change in the calibrated value—on DBG and CSG, respectively. The sensitivity of the modeled mean <italic>B</italic><sub><italic>a</italic></sub> to 1°C change in air temperature and 10% change in precipitation, respectively is higher on DBG (−0.50 m w.e. a<sup>−1°</sup>C<sup>−1</sup>, 0.23 m w.e. a<sup>−1</sup>) than the CSG (−0.30 m w.e. a<sup>−1°</sup>C<sup>−1</sup>, 0.13 m w.e. a<sup>−1</sup>). This study provides insights into the regional variations in mass-wastage governing SEB fluxes at a glacier-wide scale, which is helpful for understanding the glacier–climate interactions in the Himalaya and stresses an inclusion of sublimation scheme in T-index models.</p>