2022
  • Non-ICIMOD publication
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Mass- and Energy-Balance Modeling and Sublimation Losses on Dokriani Bamak and Chhota Shigri Glaciers in Himalaya Since 1979

  • Srivastava S.
  • Azam M.F.
  • Summary
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 (Ba) 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 Ba 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 in-situ Ba and validated against available in-situ altitudinal and geodetic mass balances. DBG and CSG show mean Ba of −0.27 ± 0.32 and −0.31 ± 0.38 m w.e. a−1 (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 Ba is highly sensitive to snow albedo —with sensitivities of 0.29 and 0.37 m w.e. a−1 for 10% change in the calibrated value—on DBG and CSG, respectively. The sensitivity of the modeled mean Ba to 1°C change in air temperature and 10% change in precipitation, respectively is higher on DBG (−0.50 m w.e. a−1°C−1, 0.23 m w.e. a−1) than the CSG (−0.30 m w.e. a−1°C−1, 0.13 m w.e. a−1). 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. Copyright © 2022 Srivastava and Azam.