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1دورية أكاديمية
المصدر: The Cryosphere
مصطلحات موضوعية: Surface mass-balance, Equilibrium-line altitude, Numerical simulations, Glacier volume, Climate-change, Lake district, Sheet model, Greenland, Schemes, CMIP5
الوصف: Glaciers and ice caps are thinning and retreating along the entire Andes ridge, and drivers of this mass loss vary between the different climate zones. The southern part of the Andes (Wet Andes) has the highest abundance of glaciers in number and size, and a proper understanding of ice dynamics is important to assess their evolution. In this contribution, we apply the ice-sheet model SICOPOLIS (SImulation COde for POLythermal Ice Sheets) to the Mocho-Choshuenco ice cap in the Chilean Lake District (40◦ S, 72◦ W; Wet Andes) to reproduce its current state and to project its evolution until the end of the 21st century under different global warming scenarios. First, we create a model spin-up using observed surface mass balance data on the south-eastern catchment, extrapolating them to the whole ice cap using an aspect-dependent parameterization. This spin-up is able to reproduce the most important present-day glacier features. Based on the spin-up, we then run the model 80 years into the future, forced by projected surface temperature anomalies from different global climate models under different radiative pathway scenarios to obtain estimates of the ice cap’s state by the end of the 21st century. The mean projected ice volume losses are 56 ± 16 % (RCP2.6), 81 ± 6 % (RCP4.5), and 97 ± 2 % (RCP8.5) with respect to the ice volume estimated by radio-echo sounding data from 2013. We estimate the uncertainty of our projections based on the spread of the results when forcing with different global climate models and on the uncertainty associated with the variation of the equilibrium line altitude with temperature change. Considering our results, we project a considerable deglaciation of the Chilean Lake District by the end of the 21st century. ; Australian National University CSIRO Deep Earth Imaging Future Science Platform Comision Nacional de Investigacion Cientifica y Tecnologica (CONICYT) CONICYT FONDECYT 1180785 1201967 ANID ; Versión publicada - versión final del editor
وصف الملف: application/pdf
العلاقة: The Cryosphere, 15, 3637–3654, 2021; https://repositorio.uchile.cl/handle/2250/182903Test
الإتاحة: https://doi.org/10.5194/tc-15-3637-2021Test
https://repositorio.uchile.cl/handle/2250/182903Test -
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المؤلفون: Feiteng Wang, Jing Ming, Xiaoying Yue, Huilin Li, Zhongqin Li, Zhencai Du, Lin Wang
المصدر: The Cryosphere, Vol 14, Pp 2597-2606 (2020)
مصطلحات موضوعية: lcsh:GE1-350, geography, geography.geographical_feature_category, 010504 meteorology & atmospheric sciences, lcsh:QE1-996.5, Glacier, 010501 environmental sciences, Albedo, Snow, 01 natural sciences, Current (stream), lcsh:Geology, Equilibrium line altitude, Climatology, Control area, Environmental science, Precipitation, lcsh:Environmental sciences, 0105 earth and related environmental sciences, Earth-Surface Processes, Water Science and Technology
الوصف: The glaciers in the Sawir Mountains, Altai area, have been experiencing a continuing and accelerating ice loss since 1959, although the snowfall is abundant and evenly distributed over the year. As an attempt to reduce their melting, we carried out two artificial snowfall experiments on the Muz Taw Glacier during 19–22 August 2018. We measured the albedo and mass balance at different sites along the glacier before and after the experiments. Two automatic weather stations (AWSs) were set up at the equilibrium line altitude (ELA) of the glacier as the target area and the forefield as the control area to record the precipitation, respectively. A comparison of the two precipitation records from the two AWSs suggests that natural precipitation could account for up to 21 % of the snowfall received by the glacier during the experiments. Because of the snowfalls, the glacier's surface albedo significantly increased in the middle to upper part; the average mass loss during 18–24 August (after the experiments) decreased by between 32 and 41 mm w.e (14 %–17 %) compared to during 12–18 August (before the experiments); and the mass resulting from the snowfall accounted for between 42 % and 54 % of the total melt during 18–24 August. We also propose a mechanism involving artificial snowfall, albedo, and mass balance, and the feedbacks describing the role of snowfall in reducing the melting of the glacier. The current status of the work is primitive as it is a preliminary trial, and the conclusions need more controlling experiments to validate it against larger spatio-temporal scales in future.
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::61f3a9481658db358665e481268d8dd7Test
https://tc.copernicus.org/articles/14/2597/2020/tc-14-2597-2020.pdfTest -
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المؤلفون: Roger J. Braithwaite
المصدر: Braithwaite, R J 2015, ' From Doktor Kurowski's Schneegrenze to our modern equilibrium line altitude (ELA) ', Cryosphere, vol. 9, pp. 2135-2148 . https://doi.org/10.5194/tc-9-2135-2015Test
The Cryosphere, Vol 9, Iss 6, Pp 2135-2148 (2015)مصطلحات موضوعية: lcsh:GE1-350, geography, glacier, geography.geographical_feature_category, snow line, lcsh:QE1-996.5, 19th century, Glacier, Standard deviation, lcsh:Geology, Altitude, Kurowski, Ludwig, Equilibrium line altitude, equilibrium line altitude, Earth and Planetary Sciences (miscellaneous), Snow line, Precipitation, Physical geography, Geomorphology, lcsh:Environmental sciences, Switzerland, Geology, Earth-Surface Processes, Water Science and Technology
الوصف: Translated into modern terminology, Kurowski suggested in 1891 that the equilibrium line altitude (ELA) of a glacier is equal to the mean altitude of the glacier when the whole glacier is in balance between accumulation and ablation. Kurowski's method has been widely misunderstood, partly due to inappropriate use of statistical terminology by later workers, and has been little tested except by Braithwaite and Müller in a 1980 paper (for 32 glaciers). I now compare Kurowski's mean altitude with balanced-budget ELA calculated for 103 modern glaciers with measured surface mass balance data. Kurowski's mean altitude is significantly higher (at 95% level) than balanced-budget ELA for 19 outlet and 42 valley glaciers, but not significantly higher for 34 mountain glaciers. The error in Kurowski mean altitude as a predictor of balanced-budget ELA might be due to generally lower balance gradients in accumulation area compared with ablation areas for many glaciers, as suggested by several workers, but some glaciers have higher gradients, presumably due to precipitation increase with altitude. The relatively close agreement between balanced-budget ELA and mean altitude for mountain glaciers (mean error −8 m with standard deviation 59 m) may reflect smaller altitude ranges for these glaciers such that there is less room for effects of different balance gradients to manifest themselves.
وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::07eb37062af0b19a9eac150a7f53f8eeTest
https://doi.org/10.5194/tc-9-2135-2015Test -
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المؤلفون: TN Venkatesh, J. Srinivasan, Anil V. Kulkarni
المصدر: The Cryosphere, Vol 6, Iss 2, Pp 301-311 (2012)
مصطلحات موضوعية: lcsh:GE1-350, geography, geography.geographical_feature_category, lcsh:QE1-996.5, Glacier, Structural basin, lcsh:Geology, Equilibrium line altitude, Satellite data, Climatology, Period (geology), Surge, Divecha Centre for Climate Change, Geology, lcsh:Environmental sciences, Earth-Surface Processes, Water Science and Technology
الوصف: It has been observed that a majority of glaciers in the Himalayas have been retreating. In this paper, we show that there are two major factors which control the advance/retreat of the Himalayan glaciers. They are the slope of the glacier and changes in the equilibrium line altitude. While it is well known, that these factors are important, we propose a new way of combining them and use it to predict retreat. The functional form of this model has been derived from numerical simulations using an ice-flow code. The model has been successfully applied to the movement of eight Himalayan glaciers during the past 25 years. It explains why the Gangotri glacier is retreating while Zemu of nearly the same length is stationary, even if they are subject to similar environmental changes. The model has also been applied to a larger set of glaciers in the Parbati basin, for which retreat based on satellite data is available, though over a shorter time period.
وصف الملف: application/pdf
الوصول الحر: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::7d7f5449f2b11929c2814b9ebab0aed5Test
http://www.the-cryosphere.net/6/301/2012/tc-6-301-2012.pdfTest
