Abstract
Proglacial lakes are continually developing and expanding across the Himalayan glaciered terrain in response to climate change. These lakes are known to destabilize the glaciers by enhancing their frontal ablation, causing higher than average glacier area and mass losses. Thus, to comprehend the dynamics of proglacial lakes and their influence on the overall glacier health, we study the lake-terminating Dulung Glacier located in the Suru sub-basin, Ladakh, western Himalaya and compare it with the adjacent land-terminating Chilung Glacier. The pronounced melting of the Dulung Glacier, supported by glacier topography (surface gradient between accumulation and ablation zone) and valley morphology (wider near the snout and narrower downwards), seems to be the prime reason for the formation, accommodation and sustenance of the proglacial lake. The expansion in proglacial lake (.008 km2a−1) during 1977–2018 is accompanied by an enhanced degeneration of the Dulung Glacier (mass balance: −.47 ± .06 m w.e.a−1, shrinkage rate: .3 ± .001% a−1; retreat rate: 32 ± .7 ma−1, surface ice velocity reduction: 16%), which has accelerated post-1993. In comparison, land-terminating Chilung Glacier shows lower degeneration rates (mass balance: −.28 ± .02 m w.e.a−1; shrinkage rate: .2 ± .001% a−1; retreat rate: 17 ± 0.7 ma−1, surface ice velocity reduction: 8%) during 1971–2018. This suggests a substantial impact of the proglacial lake in enhancing the Dulung Glacier’s sensitivity towards climate change compared to the Chilung Glacier. If the current rate of lake expansion continues, it would further enhance the Dulung Glaciers’ degeneration rates, thus impacting its stability.
Highlights
The Himalayan glaciers’ response has markedly changed due to climate fluctuations in the last few decades (Kumar et al, 2005)
The present study focuses on the Dulung Glacier and associated proglacial lakes (PGLs) at its snout, located in the Suru sub-basin, Ladakh, western Himalaya
Corona imagery of 1971 shows that the PGL existed as a small pond (Figure 2), located at around 100 m from the Dulung Glaciers’ snout
Summary
The Himalayan glaciers’ response has markedly changed due to climate fluctuations in the last few decades (Kumar et al, 2005) This alteration is evident from the enhanced mass wastage, shrinkage and retreat of most Himalayan glaciers, with few exceptions (Bolch et al, 2012; Kulkarni and Karyakarte, 2014; Azam et al, 2018; Shukla et al, 2020b). The PGLs receive input from the meltwater generated supra-, en- or subglacially Their origin can be directly linked to the climateinduced thinning/negative mass balance of the associated laketerminating glaciers (glaciers that reach or terminate in a lake) (Reynolds, 2000; Singh et al, 2011; Kääb et al, 2012; Gardelle et al, 2013; Neckel et al, 2014; King et al, 2019). To understand the contribution of the PGLs in altering the glaciers’ response and future prediction of any hazard, it is imperative to regularly monitor and study the dynamics of PGLs
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