Region-wide glacier mass balances over the Pamir-Karakoram-Himalaya during 1999–2011

J Gardelle,A Kääb,Y Arnaud,E Berthier

doi:10.5194/tc-7-1263-2013

Abstract

Abstract. The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008–2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (−0.22 ± 0.12 m w.e. yr−1 to −0.33 ± 0.14 m w.e. yr−1) and larger losses in the western Himalaya (−0.45 ± 0.13 m w.e. yr−1). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10 ± 0.16 m w.e. yr−1) and also observed for glaciers in the western Pamir (+0.14 ± 0.13 m w.e. yr−1). Thus, the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, −0.14 ± 0.08 m w.e. yr−1, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st century.

Highlights

The Pamir-Karakoram-Himalaya (PKH) mountain ranges are covered by more than 70 000 km2 of glaciers (Arendt et al, 2012)
To estimate the regionwide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan, we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008– 2011) DEMs derived from SPOT5 stereo imagery
For the four eastern study sites, from the Hengduan Shan to the West Nepal (Fig. 1), the elevation changes averaged over the accumulation areas are small whereas clear surface lowering is observed for all four study sites in their ablation areas, ranging from −0.50 ± 0.14 m yr−1 (Bhutan) to −0.81 ± 0.13 m yr−1 (Hengduan Shan)

Summary

Introduction

The Pamir-Karakoram-Himalaya (PKH) mountain ranges are covered by more than 70 000 km of glaciers (Arendt et al, 2012). Assessing glacier evolution over such a large and remote region is challenging, but required to characterize the impacts of climate change in the region (e.g. Bolch et al, 2012), to assess glacial contribution to water resources Immerzeel et al, 2010; Kaser et al, 2010) and global sea level rise (e.g. Kääb et al, 2012; Gardner et al, 2013) and, to reliably project glacier response to 21st century climate changes Mass balance is the most relevant variable to assess glacier responses to climate variability (Oerlemans, 2001; Vincent, 2002). Remain scarce in the PKH and may not adequately sample the wide range of climates and glacier responses in the region.

Objectives

Results

Discussion

Conclusion