Recession and Morphological Changes of the Debris-Covered Milam Glacier in Gori Ganga Valley, Central Himalaya, India, Derived From Satellite Data

Suraj Mal,Udo Schickhoff,M P S Bisht,R B Singh,Manish Mehta

doi:10.3389/fenvs.2019.00042

Abstract

We analysed the recession of the Milam glacier in the Gori Ganga River valley, Uttarakhand Himalaya using historical plane-table survey maps, topographical maps, Corona image (1968), Landsat 5 TM (1990), Landsat 7 ETM+ (2001) and Sentinel 2 (2017) satellite data. We estimate that the Milam glacier has receded by 1565.4 ± 20.6 m (31.9 ± 0.4 m a-1) over the period 1968-2017, while lower recession rate (21.1 ± 1.7 m a-1) was observed between 2001 and 2017. The Milam glacier lost 2.27 ± 0.06 km2 of its area from 1968 to 2017 due to recession. Two tributary glaciers detached from the main trunk between 1990 and 2017, which indicates glacier thinning and melting. The glacier recession also resulted in deformation of moraine ridges on either sides in lower ablation zone of Milam glacier, which is caused due to the removal of basal ice support caused by glacier melting.

Highlights

The Indian Himalayan mountain system has experienced above average warming (∼0.9– 1.6◦C) over the last century (Bhutiyani et al, 2007, 2009; Dash et al, 2007; Bhutiyani, 2016; Schickhoff et al, 2016) as compared with the global average of 0.85◦C (IPCC, 2013)
Glaciers of eastern and north-western Himalaya and Karakorum mountains receive precipitation primarily from the Indian Summer Monsoon (ISM) and the mid-latitude westerlies (MLW) respectively, while central and western Himalayan glaciers are fed by both the weather systems (Ageta and Higuchi, 1984; Ageta and Fujita, 1996; Bookhagen and Burbank, 2010; Bolch et al, 2012; Scott et al, 2019)
The study reveals that the Milam glacier receded by 1565.4 ± 20.6 m from 1968 to 2017, with an average recession rate of 31.9 ± 0.4 m a−1 (Figure 2)

Summary

Introduction

The Indian Himalayan mountain system has experienced above average warming (∼0.9– 1.6◦C) over the last century (Bhutiyani et al, 2007, 2009; Dash et al, 2007; Bhutiyani, 2016; Schickhoff et al, 2016) as compared with the global average of 0.85◦C (IPCC, 2013). A review of studies on Himalayan glaciers suggests spatially variable and irregular glacier response patterns across the Karakorum-Himalayan mountain (Mayewski and Jeschke, 1979; Scherler et al, 2011; Bolch et al, 2012, 2019; Kääb et al, 2012, 2015; Schickhoff et al, 2016; Azam et al, 2018). The ISM affected glaciers (western, central and eastern Himalaya) largely shrank, while those influenced by MLW (north-western Himalaya and Karakorum) are relatively stable and some of them even show advancement (Scherler et al, 2011; Bolch et al, 2012, 2019)

Methods

Results

Discussion

Conclusion