Review of the status and mass changes of Himalayan-Karakoram glaciers

Azam, Mohd Farooq; Wagnon, Patrick; Berthier, Étienne; Vincent, Christian; Fujita, Koji; Kargel, Jeffrey S.

doi:10.1017/jog.2017.86

Cited by 272 publications

(211 citation statements)

References 140 publications

(237 reference statements)

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“…The energy balance drives the melt of the debris-covered tongues and several studies point toward a yet unexplained faster surface lowering of the tongues of these glaciers than what can be expected based on the melt suppression by thick debris (Kääb et al, 2012;Gardelle et al, 2013;Pellicciotti et al, 2015;Azam et al, 2018). It is unclear whether this behavior can be attributed to turbulent fluxes, supra-glacial features such as cliffs and ponds, a reduced emergence velocity or other processes (Vincent et al, 2016;Azam et al, 2018). Highly detailed information about the surface temperature provides LW ↑ , a term often assumed to be spatially constant and only measured point-scale at a weather station (Reid et al, 2012;Steiner and Pellicciotti, 2016).…”

Section: Applications Of Thermal Uav Imagerymentioning

confidence: 99%

Mapping Surface Temperatures on a Debris-Covered Glacier With an Unmanned Aerial Vehicle

et al. 2018

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A layer of debris cover often accumulates across the surface of glaciers in active mountain ranges with exceptionally steep terrain, such as the Andes, Himalaya, and New Zealand Alps. Such a supraglacial debris layer has a major influence on a glacier's surface energy budget, enhancing radiation absorption, and melt when the layer is thin, but insulating the ice when thicker than a few cm. Information on spatially distributed debris surface temperature has the potential to provide insight into the properties of the debris, its effects on the ice below and its influence on the near-surface boundary layer. Here, we deploy an unmanned aerial vehicle (UAV) equipped with a thermal infrared sensor on three separate missions over one day to map changing surface temperatures across the debris-covered Lirung Glacier in the Central Himalaya. We present a methodology to georeference and process the acquired thermal imagery, and correct for emissivity and sensor bias. Derived UAV surface temperatures are compared with distributed simultaneous in situ temperature measurements as well as with Landsat 8 thermal satellite imagery. Results show that the UAV-derived surface temperatures vary greatly both spatially and temporally, with −1.4 ± 1.8, 11.0 ± 5.2, and 15.3 ± 4.7 • C for the three flights (mean ± sd), respectively. The range in surface temperatures over the glacier during the morning is very large with almost 50 • C. Ground-based measurements are generally in agreement with the UAV imagery, but considerable deviations are present that are likely due to differences in measurement technique and approach, and validation is difficult as a result. The difference in spatial and temporal variability captured by the UAV as compared with much coarser satellite imagery is striking and it shows that satellite derived temperature maps should be interpreted with care. We conclude that UAVs provide a suitable means to acquire surface temperature maps of debris-covered glacier surfaces at high spatial and temporal resolution, but that there are caveats with regard to absolute temperature measurement.

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Section: Applications Of Thermal Uav Imagerymentioning

confidence: 99%

Mapping Surface Temperatures on a Debris-Covered Glacier With an Unmanned Aerial Vehicle

et al. 2018

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“…3 The Dongkemadi Region. 4 From February 2000 to February 2012. 5 From February 2000 to January 2012.…”

Section: Reconstructed Annual Mass Balance Seriesmentioning

confidence: 99%

“…These glaciers are mostly located at the headwaters of large Asian rivers such as the Yangtze, Mekong, Brahmaputra, and Indus Rivers, providing a valuable water supply in the form of meltwater for millions of people for drinking, agriculture, and manufacturing [2][3][4][5]. However, field glaciological observations (particularly mass balance (MB) measurements) in the TP remain scarce, due to challenging mountainous terrain and harsh weather conditions [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Annual Glacier-Wide Mass Balance (2000–2016) of the Interior Tibetan Plateau Reconstructed from MODIS Albedo Products

Zhang

Jiang

et al. 2018

Remote Sensing

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Glaciers in the Tibetan Plateau (TP) play a crucial role in regulating agriculture irrigation, river discharge and the regional/global climate system. However, mass balance records of TP glaciers have remained scarce due to challenging mountainous terrain and harsh weather conditions, which limits our understanding of the influence of melting glaciers on local water resources and responses to climate change. Here, we present and assess an albedo-based method to derive annual mass balance for three glaciers in the interior TP from Moderate Resolution Imaging Spectroradiometer (MODIS) albedo data during 2000-2016. A strong linear correlation (R 2 = 0.941, P < 0.001) is found between annual minimum-averaged glacier-wide albedo (AMGA) values and annual mass balance measurements on the Xiao Dongkemadi glacier. Furthermore, the 17-year-long annual mass balance series of the Xiao Dongkemadi glacier and the Geladandong mountain region glaciers, and the Purogangri ice cap are reconstructed for the first time, with a mass loss rate of 535 ± 63 mm w.e.a −1 , 243 ± 66 mm w.e.a −1 and 113 ± 68 mm w.e.a −1 , respectively. The results are verified by geodetic estimates, with relative error ranging from 4.55% to 11.80%, confirming that the albedo-based method can be used to estimate specific mass budgets for interior TP glaciers. A strong correlation between the mass balance series and air temperature infers that increasing summer air temperature may be one of main reasons for glacier shrinkage of the three studied glaciers.

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“…Glacier mass change estimates are usually based on time series of glaciological measurements, digital elevation models (DEMs) differencing, and numerical mass balance estimations (e.g., Paul et al, 2009). In recent years, the geodetic method for estimating changes in the surface elevation and volume of glaciers has been widely used Brun et al, 2017;Azam et al, 2018;Robson et al, 2018). The data were used not only to estimate decadal mass changes but also to correct and reanalyse long-term glaciological mass balance measurements (Zemp et al, 2013;Sold et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Volume Changes of Elbrus Glaciers From 1997 to 2017

et al. 2019

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This study describes the analysis of changes in area and volume of the Mt.Elbrus glacier system, Central Caucasus from 1997 to 2017. It is based on helicopter-borne ice thickness measurements, comparison of high-resolution imagery and two digital elevation models (DEMs) with 10 m resolution. More than 250 km of ground-penetrating radar (GPR) profiles of ice thickness with reliable reflections were obtained. The total volume of Mt. Elbrus glaciers was 5.03 ± 0.85 km 3 of ice in 2017. Our results show that 68% of the total ice volume is concentrated below 4,000 m a.s.l. where the average ice thickness was 44.6 ± 7.3 m, 18% of the volume lies within 4,000-4,500 m a.s.l. (thickness of 41.2 ± 7.3 m), and just 14% lies above 4,500 m a.s.l. (thickness of 29.7 ± 6.7 m). The glacier-covered area of Mt. Elbrus decreased from 125.76 ± 0.65 km 2 in 1997 to 112.20 ± 0.58 km 2 in 2017, a reduction of 10.8%. Over the same period the volume decreased by 22.8%. The mass balance of the Elbrus glaciers decreased by −0.55 ± 0.04 m w.e. a −1 from 1997 to 2017. Mass balance on west-oriented glaciers is less negative than on east-and south-oriented glaciers where mass balance is most negative. The mass balance of the east-oriented Djikiugankez glacier decreased at the fastest average rate (−0.97 ± 0.07 m w.e. a −1 ). This glacier contains 28% of the total Elbrus glacier system ice volume, most of which is concentrated below 4,000 m a.s.l. Only one small glacier on the western slope demonstrated mass gain. Our results match well with the long term direct mass balance measurements on the Garabashi glacier on Elbrus which lost 12.58 m w.e. and 12.92 ± 0.95 m w.e. between 1997 and 2017 estimated by glaciological and geodetic method, respectively. The rate of Elbrus glacier mass loss tripled in 1997-2017 compared with the 1957-1997 period.

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Review of the status and mass changes of Himalayan-Karakoram glaciers

Cited by 272 publications

References 140 publications

Mapping Surface Temperatures on a Debris-Covered Glacier With an Unmanned Aerial Vehicle

Mapping Surface Temperatures on a Debris-Covered Glacier With an Unmanned Aerial Vehicle

Annual Glacier-Wide Mass Balance (2000–2016) of the Interior Tibetan Plateau Reconstructed from MODIS Albedo Products

Volume Changes of Elbrus Glaciers From 1997 to 2017

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