Snow and ice melt contributions in a highly glacierized catchment of Chhota Shigri Glacier (India) over the last five decades

Abstract

Glacier-wide mass balances and runoffs are reconstructed over 1969–2016 for Chhota Shigri Glacier catchment (India) applying a glacio-hydrological model. The model is forced using in-situ daily air-temperature and precipitation records from the meteorological stations at Bhuntar Observatory (1092 m a.s.l.), glacier base camp (3850 m a.s.l.) and glacier side moraine (4863 m a.s.l.). The modelled mean annual mass balance is −0.30 ± 0.36 m w.e.a−1 (meter water equivalent per year), while the mean catchment-wide runoff is 1.56 ± 0.23 m w.e.a−1 over 1969–2016. Three periods are distinguished in the reconstructed mass balance and runoff series. Periods I (1969–1985) and III (2001–2016) show glacier mass wastage at rates of −0.36 and −0.50 m w.e.a−1, respectively, corresponding to catchment-wide runoffs of 1.51 and 1.65 m w.e.a−1, respectively. Conversely, period II (1986–2000) exhibits steady-state conditions with average mass balances of −0.01 m w.e.a−1, and corresponding runoff of 1.52 m w.e.a−1. The reduced ice melt (0.20 m w.e.a−1) over period II, in agreement with steady-state conditions, is compensated by the increased snow melt (1.03 m w.e.a−1), providing almost similar catchment-wide runoffs for period I and II. The increased runoff after 2000 is mainly governed by increased ice melt (0.32 m w.e.a−1) over period III. Snow accumulation in winter and summer seasons together control the glacier-wide mass balances as well as catchment-wide runoffs. Snow melt contributes the maximum to the total mean annual runoff with 63% share while glacier melt and rain contribute 17% and 20% respectively over the whole period.