Temporal inventory of glaciers in the Suru sub-basin, western Himalaya: Impacts of the regional climate variability

Abstract

Abstract. Updated knowledge about the glacier extent and characteristics in the Himalaya cannot be overemphasised. Availability of precise glacier inventories in the latitudinally diverse western Himalayan region is particularly crucial. In this study we have created an inventory of the Suru sub-basin, western Himalaya for year 2017 using Landsat OLI data. Changes in glacier parameters have also been monitored from 1971 to 2017 using temporal satellite remote sensing data and limited field observations. Inventory data shows that the sub-basin has 252 glaciers covering 11 % of the basin, having an average slope of 25 ± 6° and dominantly north orientation. The average snow line altitude (SLA) of the basin is 5011 ± 54 masl with smaller (47 %) and cleaner (43 %) glaciers occupying the bulk area. Longterm climate data (1901–2017) shows an increase in the mean annual temperature (Tmin & Tmax) by 0.77 ºC (0.25 & 1.3 ºC) in the sub-basin, driving the overall glacier variability in the region. Temporal analysis reveals a glacier shrinkage of ~ 6 ± 0.02 %, an average retreat rate of 4.3 ± 1.02 ma−1, debris increase of 62 % and 22 ± 60 m SLA rise in past 46 years. This confirms their transitional response between the Karakoram and the Greater Himalayan Range (GHR) glaciers. Besides, glaciers in the sub-basin occupy two major ranges, i.e., GHR and Ladakh range (LR) and experience local climate variability, with the GHR glaciers exhibiting a warmer and wetter climate as compared to the LR glaciers. This variability manifestes itself in the varied response of GHR and LR glaciers. While the GHR glaciers exhibit an overall rise in SLA (GHR: 49 ± 69 m; LR: decrease by 18 ± 50 m), the LR glaciers have deglaciated more (LR: 7 %; GHR: 6 %) with an enhanced accumulation of debris cover (LR: 73 %; GHR: 59 %). Inferences from this study reveal prevalence of glacier disintegration and overall degeneration, transition of clean ice to partially debris covered glaciers, local climate variability and non-climatic (topographic and morphometric) factor induced heterogeinty in glacier response as the major processes operatives in this region. The dataset (Shukla et al., 2019) is accessible at https://doi.pangaea.de/10.1594/PANGAEA.904131.

Multitemporal glacier inventory revealing four decades of glacier changes in the Ladakh region

“…Error due to sources 1, 3 and 4 are generally minor and can be visually identified and corrected (Sect. 3.3), but an exact quantification is difficult due to the lack of reference data available from the region (Racoviteanu et al, 2009;Shukla et al, 2020). Type 4 errors are significant and have an impact on both glacier area and length estimation.…”

“…In high altitude arid regions like Ladakh, where the majority of glaciers are small and restricted to higher altitudes, meltwater serves as an important driver of the economy, especially in years with low winter precipitation when glacier melt becomes the major (or only) source of water Nüsser, 2012, 2017). Recent studies have reported that Himalayan glaciers are retreating at an alarming rate (Azam et al, 2021;Bolch, 2019;Kääb et al, 2015;Maurer et al, 2019;Pritchard, 2019;Shean et al, 2020, among others) with glaciers of the Western Himalayas showing less shrinkage than the glaciers of the central and eastern parts (Azam et al, 2021;Shukla et al, 2020;Singh et al, 2016). Glaciers in the nearby Karakoram region display long-term irregular behaviour with frequent glacier advances/surges and minimal shrinkage, which is yet to be fully understood (Azam et al, 2021;Bhambri et al, 2013;Bolch et al, 2012;Liu et al, 2006;Minora et al, 2013;Negi et al, 2021).…”

“…Few studies have focused on the glaciers of this region (e.g. Bhambri et al, 2011Bhambri et al, , 2013Chudley et al, 2017;Negi et al, 2021;Nüsser et al, 2012;Nüsser, 2012, 2017;Shukla et al, 2020).…”

Evaluation of the global glacier inventories and assessment of glacier elevation changes over north-western Himalaya

“…Despite the usefulness of the global and regional glacier inventories for various applications at local, 105 regional and global scales, the reproducibility of the results for various applications in different regions is not assured (Nagai et al, 2016). In addition to the global glacier inventory databases compared and discussed in this paper, a few more glacier inventories (Shukla et al, 2020) and mass balance (Vijay and Braun, 2018) databases from the Himalaya have been recently published online. However, the glacier inventory database by Shukla et al, (2020), restricted 110 to the Suru basin, is primarily based on the automatic approach (normalized-difference snow index) unlike the present study where the glaciers are mapped manually using on-screen digitization.…”

“…In addition to the global glacier inventory databases compared and discussed in this paper, a few more glacier inventories (Shukla et al, 2020) and mass balance (Vijay and Braun, 2018) databases from the Himalaya have been recently published online. However, the glacier inventory database by Shukla et al, (2020), restricted 110 to the Suru basin, is primarily based on the automatic approach (normalized-difference snow index) unlike the present study where the glaciers are mapped manually using on-screen digitization. The uncertainties in glacier mapping using the automatic method are considerably minimized by manually delineating the glacier extents (Paul et al, 2013;Rashid and Abdullah, 2016).…”