Spatially distributed ice-thickness modelling for Chhota Shigri Glacier in western Himalayas, India

Ramsankaran, Raaj; Pandit, Ankur; Azam, Mohd Farooq

doi:10.1080/01431161.2018.1441563

Cited by 58 publications

(55 citation statements)

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“…3c-g. The uncertainty in the estimation of glacier volume depends on the error in the ice thickness calculation and has been quantified using the error propagation method 31 . According to our calculation, the total ice volume of Batura in 2000 is estimated as 18.88 ± 4.79 km 3 ( Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…improvement of ice thickness calculation. Basal shear stress and shape factor are the key parameters in thickness calculation 4,31,35 , which was optimized by measured ice thickness. Several studies on mountain valley glaciers have revealed that the shear stress on the glacier's bed ranges from 30 to 160 kPa [36][37][38] .…”

Section: Discussionmentioning

confidence: 99%

“…Debris impact cannot be omitted in ice thickness calculation. It has been reported that the shape factors related to the lateral drag predominated because of the friction of the valley walls and the general form of the glacier cross-section 31,43 . It depends specifically on the ratio of its half-width to the centerline thickness by Nye 44 .…”

Section: Discussionmentioning

confidence: 99%

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Post-20th century near-steady state of Batura Glacier: observational evidence of Karakoram Anomaly

Gao

Zou

et al. 2020

Sci Rep

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Stable or marginal mass loss dominating in Karakoram has been reported widely through satellite and ground investigations. this work aimed to verify the variation in glacier mass by collecting groundbased data. By tracking profiles from the first survey by China-Pakistan Batura Glacier Investigation Group in 1974-1975, we revisited Batura Glacier and conducted an updated comparable measurement of the glacier surface elevation and ice thickness of this large valley glacier of Karakoram, in August 2017. Results of ground penetrating radar (GPR) measurement were used to improve the accuracy of an ice thickness distribution model (GlabTop2). The model calculation agreed reasonably with the measurement when the optimal basal shear stress (100 kPa for clean ice to 140 kPa for heavy debris cover) and shape factor (0.9) were used. We then used a glacier bed topographies map to calculate the ice flux. By subtracting the glacier surface topographies from the remote-sensing measurements, we observed a marginal thinning in Batura during 2000-2016, with a rate of variation in glacier surface elevation of −0.12 ± 0.27 m a −1. it indicated that the mass gain in the accumulation area nearly compensated the mass loss in the ablation area. In addition, both ground and satellite remote measurement reveal a steady rate of decrease in surface of the Batura tongue, implying an absence of significant variation during the past 40 years. Moreover, the mass conservation equation was applied to the Batura tongue, in combination with surface elevation variation and ice flux evolution. The tongueaveraged mass balance diminished by more than half from the 1970s to the 2010s. In summary, we inferred a near-steady state of Batura Glacier post 2000 based on the above-mentioned evidence of "Karakoram Anomaly". Glaciers are important water resources and exceptionally sensitive indicators of climate change. Glacier melt water plays an important role in the Indus basin 1 owing to its extensive upstream and glaciated area. Millions of humans rely on the meltwater from the Upper Indus Basin (UIB). The glacial response to climate change in this region has important ramifications for future water availability from UIB. UIB is composed of the Hindukush, Karakoram, and Himalayan mountains (HKH). It has the highest concentration of glaciers outside the polar regions 2. The glaciers cover 12,705 km 2. Of this, over 70% is in the Karakoram region 3. However, there is high variability in the glacier ice volume estimates of the Karakoram region, ranging from 1683 to 2827 km 3 by different approaches 4. Measured ice thickness data can be applied to validate and increase the accuracy of volume estimation at the regional scale 5,6. Measurements of the ice thickness in High Mountain Asia are few compared with those of the glacier amount. In addition, glaciers here have displayed an unusual behavior during the past decades: an absence of significant area variations 7 , rather, frequent advances and surge activities 8,9. Stable or marginal mass loss dominate in Kara...

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Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Post-20th century near-steady state of Batura Glacier: observational evidence of Karakoram Anomaly

Gao

Zou

et al. 2020

Sci Rep

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“…Ordered by the glacier area for which a solution was provided ( Fig. 1), the models included those by Huss and Farinotti 30 (Model 1), Frey et al 29 (Model 2), Maussion et al 33 (Model 3), Fürst et al 32 (Model 4) and Ramsankaran et al 34 (Model 5). These models are capable of inverting for glacier ice thickness distributions at the mountain range scale.…”

Section: Methodsmentioning

confidence: 99%

“…Here we take advantage of the ITMIX findings and use a combination of up to five ice thickness estimation models 29,30,[32][33][34] ( Fig. 1) to provide an ensemble-based estimate for the ice thickness distribution of each of the about 215,000 glaciers included in the Randolph Glacier Inventory (RGI) version 6.0 (ref.…”

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confidence: 99%

A consensus estimate for the ice thickness distribution of all glaciers on Earth

et al. 2019

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G laciers and ice caps outside the Greenland and Antarctic ice sheets ('glaciers' in the following) are changing rapidly in response to climate change 1 . Although they only contain a fraction of the worldwide ice volume 2 , the consequences of their mass loss are widespread and of global significance: glacier changes affect global trends in freshwater availability 3,4 , have dominated cryospheric contributions to recent sea level changes 5,6 and are anticipated to affect regional water resources over the twenty-first century 7,8 . Clearly, projections of such impacts require an estimate of the ice volume stored within present-day glaciers, and for regionalto local-scale projections the ice thickness distribution can also be essential 9,10 . Recent studies showed that even small features in the bedrock topography can cause decadal-scale variations in both ice dynamics response 11 and subglacial water discharge 12 .Despite far-reaching implications, knowledge of the ice thickness distributions of the world's glaciers is remarkably limited. The Glacier Thickness Database (GlaThiDa), which centralizes ice thickness measurements outside the two ice sheets, presently contains information for only about 1,000 out of the 215,000 glaciers worldwide 13 . This is despite important advances in the instrumentation used to measure ice thickness 14,15 , with airborne platforms now capable of operating in mountainous environments as well 16 .Owing to the lack of direct measurements, relations between glacier area and ice volume 17 have traditionally been used to estimate global glacier volumes 18-21 . For individual glaciers, instead, a suite of methods that infer the spatial ice thickness distribution from surface characteristics have been proposed [22][23][24][25][26][27] . Such methods use topographical information-typically extracted from digital elevation models (DEMs)-to estimate the distribution of the glacier's surface mass balance and, hence, its mass turnover. Knowledge of the ice thickness distribution of the world's glaciers is a fundamental prerequisite for a range of studies.Projections of future glacier change, estimates of the available freshwater resources or assessments of potential sea-level rise all need glacier ice thickness to be accurately constrained. Previous estimates of global glacier volumes are mostly based on scaling relations between glacier area and volume, and only one study provides global-scale information on the ice thickness distribution of individual glaciers. Here we use an ensemble of up to five models to provide a consensus estimate for the ice thickness distribution of all the about 215,000 glaciers outside the Greenland and Antarctic ice sheets. The models use principles of ice flow dynamics to invert for ice thickness from surface characteristics. We find a total volume of 158 ± 41 × 10 3 km 3 , which is equivalent to 0.32 ± 0.08 m of sea-level change when the fraction of ice located below present-day sea level (roughly 15%) is subtracted. Our results indicate that High Mountain Asia ...

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Glacier Ice Thickness Estimation in Indian Himalaya Using Geophysical Methods

Mishra¹,

and²,

Shankar³

2022

Advances in Remote Sensing Technology and the Three Poles

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Spatially distributed ice-thickness modelling for Chhota Shigri Glacier in western Himalayas, India

Cited by 58 publications

References 56 publications

Post-20th century near-steady state of Batura Glacier: observational evidence of Karakoram Anomaly

Post-20th century near-steady state of Batura Glacier: observational evidence of Karakoram Anomaly

A consensus estimate for the ice thickness distribution of all glaciers on Earth

Glacier Ice Thickness Estimation in Indian Himalaya Using Geophysical Methods

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