Abstract
Abstract. The volume change of the Chhota Shigri Glacier (India, 32° 20 N, 77° 30' E) between 1988 and 2010 has been determined using in situ geodetic measurements. This glacier has experienced only a slight mass loss between 1988 and 2010 (−3.8 ± 2.0 m w.e. (water equivalent) corresponding to −0.17 ± 0.09 m w.e. yr−1). Using satellite digital elevation models (DEM) differencing and field measurements, we measure a negative mass balance (MB) between 1999 and 2010 (−4.8 ± 1.8 m w.e. corresponding to −0.44 ± 0.16 m w.e. yr−1). Thus, we deduce a slightly positive or near-zero MB between 1988 and 1999 (+1.0 ± 2.7 m w.e. corresponding to +0.09 ± 0.24 m w.e. yr−1). Furthermore, satellite DEM differencing reveals that the MB of the Chhota Shigri Glacier (−0.39 ± 0.15 m w.e. yr−1) has been only slightly less negative than the MB of a 2110 km2 glaciarized area in the Lahaul and Spiti region (−0.44 ± 0.09 m w.e. yr−1) during 1999−2011. Hence, we conclude that the ice wastage is probably moderate in this region over the last 22 yr, with near equilibrium conditions during the nineties, and an ice mass loss after. The turning point from balanced to negative mass budget is not known but lies probably in the late nineties and at the latest in 1999. This positive or near-zero MB for Chhota Shigri Glacier (and probably for the surrounding glaciers of the Lahaul and Spiti region) during at least part of the 1990s contrasts with a recent compilation of MB data in the Himalayan range that indicated ice wastage since 1975. However, in agreement with this compilation, we confirm more negative balances since the beginning of the 21st century.
Highlights
Glaciers have been recognized as good climatic indicators (e.g. Oerlemans, 2001), especially in high remote areas such as the Himalayas where meteorological observations are difficult and, only recent and sparse (e.g. Shekhar et al, 2010)
We conclude that the ice wastage is probably moderate in this region over the last 22 yr, with near equilibrium conditions during the nineties, and an ice mass loss after
A positive or near-zero mass balance (MB) for the Chhota Shigri Glacier in the 1990s departs from the most recent compilation for the entire HK (Bolch et al, 2012). This compilation indicates ice wastage over the past five decades with an increased rate of loss roughly after 1995, but with a high spatiotemporal variability. We suggest that those HK MB averages during the 90s should be regarded with caution given the scarcity of MB data and our new evidences that the Chhota Shigri Glacier had a balanced mass budget during 1988-1999
Summary
Glaciers have been recognized as good climatic indicators (e.g. Oerlemans, 2001), especially in high remote areas such as the Himalayas where meteorological observations are difficult and, only recent and sparse (e.g. Shekhar et al, 2010). Scherler et al, 2011; Bhambri et al, 2011) These length and area variations cannot be directly interpreted as direct indicators of climate change on an annual or decadal timescale due to the lag in the response time of glaciers (Cuffey and Paterson, 2010) and because most of these glaciers are partly covered by debris that strongly affects the relationship between the surface energy balance and melting (Fujita and Nuimura, 2011). Snout fluctuations obtained from satellite or aerial images are subject to uncertainty due to difficulties in delineating debris-covered glacier tongues, which are not identifiable on images For these reasons, glacier trends obtained from snout fluctuations alone in the Himalayas provide only a partial picture of glacier variability (Raina, 2009). The best indicator of climate change is the glacier-wide mass balance (MB) which results mainly from climate variables such as solid precipitation and heat and radiative fluxes via ablation (Oerlemans, 2001) provided that the MB is measured on a surface free of debris
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