scholarly journals Carbon dioxide flux in the ablation area of Koxkar glacier, western Tien Shan, China

2014 ◽  
Vol 55 (66) ◽  
pp. 231-238 ◽  
Author(s):  
Jian Wang ◽  
Haidong Han ◽  
Shiqiang Zhang
Keyword(s):  
Carbon Dioxide Flux ◽  
Mineral Weathering ◽  
Tien Shan ◽  
Ice Melting ◽  
New Approach ◽  
Glacier System ◽  
Analog Modeling ◽  
Koxkar Glacier ◽  
Glacier Ablation ◽  
Global Cycle

AbstractAccelerating loss of glacial mass caused by rising global temperatures has significant implications. The global cycle of the greenhouse gas CO2 is also associated with mineral weathering and glaciation. In glaciated areas, most estimates of atmospheric CO2 consumption are confined to chemical ionic mass balance or analog modeling methods. We applied the gradient method to the surface of Koxkar glacier, western Tien Shan, China, for a 5 month period during 2012. The overall net glacier-system CO2 exchange (NGE) rate was measured as -0.05 and -0.07mmol m–2 s–1 for regions of exposed ice and supraglacial moraine, respectively. This suggests that atmospheric CO2 drawdown may occur during ice melting because of consumption of H+ by CO2 hydrolysis that occurs in solutions. Using the degree-day model to calculate glacier ablation in bare-ice regions and considering characteristics of the NGE rate in the supraglacial debris region with the support of GIS, the daily NGE rate was estimated to be -1.23 ± 0.17μmmol m–2 d–1 between Julian days 125 and 268 of 2012. These findings present a new approach for modeling the dynamics of glacial CO2 sinks undergoing melting, and develop an understanding of the mechanism of atmospheric CO2 exchange.

scholarly journals Health and sustainability of glaciers in High Mountain Asia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Evan Miles ◽  
Michael McCarthy ◽  
Amaury Dehecq ◽  
Marin Kneib ◽  
Stefan Fugger ◽  
...  
Keyword(s):  
Current Knowledge ◽  
Field Measurements ◽  
Tien Shan ◽  
High Mountain ◽  
Specific Mass ◽  
Ice Flow ◽  
Ice Volume ◽  
Mass Redistribution ◽  
Glacier Ablation

AbstractGlaciers in High Mountain Asia generate meltwater that supports the water needs of 250 million people, but current knowledge of annual accumulation and ablation is limited to sparse field measurements biased in location and glacier size. Here, we present altitudinally-resolved specific mass balances (surface, internal, and basal combined) for 5527 glaciers in High Mountain Asia for 2000–2016, derived by correcting observed glacier thinning patterns for mass redistribution due to ice flow. We find that 41% of glaciers accumulated mass over less than 20% of their area, and only 60% ± 10% of regional annual ablation was compensated by accumulation. Even without 21st century warming, 21% ± 1% of ice volume will be lost by 2100 due to current climatic-geometric imbalance, representing a reduction in glacier ablation into rivers of 28% ± 1%. The ablation of glaciers in the Himalayas and Tien Shan was mostly unsustainable and ice volume in these regions will reduce by at least 30% by 2100. The most important and vulnerable glacier-fed river basins (Amu Darya, Indus, Syr Darya, Tarim Interior) were supplied with >50% sustainable glacier ablation but will see long-term reductions in ice mass and glacier meltwater supply regardless of the Karakoram Anomaly.

scholarly journals A simple model to estimate ice ablation under a thick debris layer

2006 ◽  
Vol 52 (179) ◽  
pp. 528-536 ◽  
Author(s):  
Han Haidong ◽  
Ding Yongjing ◽  
Liu Shiyin
Keyword(s):  
Heat Flux ◽  
Simple Model ◽  
Iterative Procedure ◽  
Indirect Comparison ◽  
Tien Shan ◽  
Balance Model ◽  
Complex Phase ◽  
Proposed Model ◽  
Koxkar Glacier

AbstractThis paper presents a simple model to estimate ice ablation under a thick supraglacial debris cover. The key method employed in the model is to establish a link between the debris heat flux and the debris temperature at a certain depth when the heat transfer in the debris is described by a diffusion process. Given surface temperature, debris thermal properties and relevant boundary conditions, the proposed model can estimate mean debris temperature at interfaces of different debris layers using an iterative procedure, and then the heat flux for ice ablation. The advantage of the proposed model is that it only requires a few parameters to conduct the modeling, which is simpler and more applicable than others. The case study on Koxkar glacier, west Tien Shan, China, shows, in general, that the proposed model gives good results for the prediction of debris temperatures, except for an apparent phase shift between modeled and observed values. We suggest that this error is mainly due to complex phase relations between debris temperature and debris heat flux. The modeled ablation rates at three experimental sites also show good results, using a direct comparison with observed data and an indirect comparison with a commonly used energy-balance model.

scholarly journals Mass-balance variability as a base for interpreting ice-core data

1995 ◽  
Vol 21 ◽  
pp. 201-205
Author(s):  
V. N. Mikhalenko
Keyword(s):  
Mass Balance ◽  
Extreme Values ◽  
Ice Core ◽  
Ice Cores ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Similarity Type ◽  
Glacier System ◽  
Point Analysis ◽  
Drilling Site

The spatial extrapolation of data from ice cores depends on the complexity of the glacier system where the drilling site is located. The correlation between net mass balance, bn, of a specific point and of the whole glacier is different for each point. Analysis of net mass balance of Tuyuksu glacier in the Tien Shan, central Asia, confirms that the distribution of mass balance with height is more-or-less constant from year to year except in years with extreme values bn. Two types of “similarity” are described, additive and multiplicative. The “similarity” changes gradually from additive at the peripheral parts of the Tien Shan to multiplicative in the most continental central and eastern parts. Glacier mass-balance fluctuations of the frontal ridges are connected to the oscillations of accumulation and consequently to precipitation. Where the climate is more continental the mass-balance variability depends much more on the melting conditions than on accumulation. For the spatial interpretation of ice-core drilling results, a special analysis of “similarity type” is necessary. It allows the fixing of the spatial borders of the glacier system for which the dhilling site is representative.

scholarly journals An experimental study of the water and heat balance in the source area of the Ürümqi River in the Tien Shan mountains

1992 ◽  
Vol 16 ◽  
pp. 55-66 ◽  
Author(s):  
Kang Ersi ◽  
Yang Daqing ◽  
Zhang Yinsheng ◽  
Yang Xinyuan ◽  
Shi Yafeng
Keyword(s):  
Heat Input ◽  
Source Area ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Equilibrium Line Altitude ◽  
Glacier Melt ◽  
Annual Total ◽  
Almost All ◽  
Glacier Ablation ◽  
Tien Shan Mountains

In the source area of the Ürümqi River, during the glacier ablation season, net radiation is the only heat input to the tundra, averaging 119W m−2 in July and August, more than twice that to the glacier, where additional heat input is contributed by sensible heat. The heat input to the tundra is mostly lost by evaporation, which accounts for 86%, while the input to the glacier is mostly lost by melting. The relatively small heat input to the glacier and the large evaporation rate of its surroundings favour the glacier’s existence. Most precipitation occurs between June and August, accounting for 66% of the annual total. Precipitation increases with altitude in average conditions during the ablation season; the annual precipitation is estimated to be about 650 mm at the mean equilibrium line altitude of 4030 m. This amount is considerably larger than that of the surrounding area. Evaporation is estimated at 270 mm a−1 on the tundra, reducing the runofTin a rather large proportion, and 120 mm a−1 on the glacier. Almost all runoff takes place between May and September, and is mostly concentrated in July and August when the glacier melt is the most intense. When air temperature is high during the ablation period, although the precipitation is less, runoff could peak because of the glacier melt. Based on the measured runoff and estimated regional precipitation and evaporation, the glacier mass balance is calculated and discussed.

Glacial regime of the highest Tien Shan mountain, Pobeda-Khan Tengry massif

1997 ◽  
Vol 43 (145) ◽  
pp. 503-512 ◽  
Author(s):  
Vladimir B. Aizen ◽  
Elena M. Aizen ◽  
Jeff Dozier ◽  
John M. Melack ◽  
David D. Sexton ◽  
...  
Keyword(s):  
Solar Radiation ◽  
Heat Balance ◽  
Tien Shan ◽  
Ice Formation ◽  
Evaporation And Condensation ◽  
Glacier System ◽  
Isotopic Analyses ◽  
Term Data ◽  
Upper Boundary

AbstractMajor processes controlling the existence of a large sub-continental glacier system were identified on the basis of glaciological, meteorological and isotopic analyses using expeditionary and long-term data. Observations were made on the southern Inylchek glacier located in the Pobeda-Khan Tengry massif, the largest sub-continental glacier system on the northern periphery of central Asia. More than 1200 glaciers with a total area of about 4320 km2comprise the massif. Melt is for the most part caused by radiation and is most intensive during periods of anticyclonic weather with fohn development. The proportion of solar radiation input in relation to heat balance is more than 90%. Evaporation and condensation are negligible during most times and comprise 7% of heat expenditure. Accumulation was associated with cold cyclonic weather. Four ice-formation zones were identified, the upper boundary of liquid runoff is at 5200 m and the recryslallization zone is above 5900 m. The calculated net glacier mass is negative, −318 kg m−2a−1, and indicates the degradation of modern Pobeda-Khan Tengry glaciers.

Mathematical simulation of melting mountain glaciers

2020 ◽  
Author(s):  
Egor Belozerov ◽  
Ekaterina Rets ◽  
Viktor Popovnin
Keyword(s):  
Mathematical Simulation ◽  
Warm Season ◽  
Weather Conditions ◽  
Tien Shan ◽  
Ice Melting ◽  
Mountain Areas ◽  
Glacier Surface ◽  
Mountain Glaciers ◽  
The Republic ◽  
Snow And Ice

<p>Freshwater shortage is one of the global problems of our time. Glaciers contain a large amount of freshwater on the Earth. Nowadays mountain glaciation is decreasing almost throughout the world (Panov, 1993; Duethmann et al., 2016; Fausto et al. 2016). This effect leads to an increase in the water content of mountain rivers, but also cause a decrease in glaciers freshwater reserves (Trenberth et al., 2007; Sorg et al., 2012). This impact is already felt in the arid regions of our planet. Recently in Central Asia was observed a shortage of water resources. According to the estimates, the total area and mass decrease of the Tien Shan glaciers, from 1961 to 2012, amountes to 18 ± 6% and 27 ± 15% (Farinotti et al., 2015). The degradation of the area and volume of the Tien Shan glaciers, in the period from 1961 to 2012, was 18 ± 6% and 27 ± 15% (Farinotti et al., 2015). About 15% of the runoff in the Republic of Kyrgyzstan is fed by glacial nutrition, but this contribution may even be 1.5-3 times greater during the warm season (Dikikh et al., 1995; Kemmerikh, 1972). The average annual rivers runoff in the Republic of Kyrgyzstan increased from 47.1 km3 (~ 1947–1972) to 50 km3 (1973–2000) (Mamatkanov et al., 2006). The representative glacier of the Central Caucasus - Dzhankuat can serve as an example of depletion of freshwater in the glaciers of the Caucasus. Over the past decades, since 1974, the Dzhankuat glacier has lost large volumes - almost twice, and at the time of 2013 it is equal to 0.077 ± 0.002 km<sup>3</sup>. From 2006 to 2015 the volume of the Dzhankuat glacier decreased by 25%, as a consequence, there is an increase in the rate of degradation (Lavrentiev et al., 2014).</p><p>In this article is presented mathematical simulation, which allows to solve a number of problems. One of the most important problem is the calculation of the water supply into the river network because of snow and ice melting in mountain areas. Weather conditions are taken into account in the simulation calculation of snow and ice melting over the entire glacier surface.</p><p>This work is supported by the Presidential Russian Federation grant №MK-2936.2019.5</p>

The challenge of non-stationary feedbacks within the response of debris-covered glaciers to climate forcing

2020 ◽  
Author(s):  
Anna Wirbel ◽  
Lindsey Nicholson ◽  
Christoph Mayer ◽  
Astrid Lambrecht
Keyword(s):  
Steady State ◽  
Climate Forcing ◽  
Dynamic Component ◽  
Mountain Ranges ◽  
Glacier System ◽  
Ablation Regime ◽  
Debris Cover ◽  
Glacier Ablation ◽  
The Impact ◽  
Development And Evolution

<p><strong>The challenge of non-stationary feedbacks within the response of debris-covered glaciers to climate forcing</strong></p><p>Debris-covered glaciers are a feature of many mountain ranges around the world and their proportion is expected to increase under continued climate warming.</p><p>The impact of debris cover on glacier behavior, via its profound modification of the glacier ablation regime, causes debris-covered glaciers to respond to the same climate forcing in a markedly different way to clean ice glaciers. In order to better understand how debris cover impacts the glacier’s response to climate forcing, we revisit the concept of steady state and examine it for a debris-covered glacier system. We present simple modeling results to explore how the development and evolution of debris cover affects the potential for steady-state and how feedbacks instigated by supraglacial debris cover complicate the glacier’s response to a prescribed steady climate. These investigations highlight the non-stationarity induced by the presence of debris and as a result, that debris cannot be considered as a static component, as it is a highly dynamic component which affects the glacier system in different ways.</p><p><br><br></p>

scholarly journals Modeling the response of glacier systems to climate warming in China

2006 ◽  
Vol 43 ◽  
pp. 313-316 ◽  
Author(s):  
Zi-Chu Xie ◽  
Xin Wang ◽  
Qing-Hua Feng ◽  
Er’si Kang ◽  
Chao-Hai Liu ◽  
...  
Keyword(s):  
Steady State ◽  
Climate Warming ◽  
Temperature Increase ◽  
Summer Temperature ◽  
Equilibrium Line ◽  
Glacier System ◽  
Median Size ◽  
Functional Models ◽  
Climatic Scenarios ◽  
Glacier Ablation

AbstractA glacier system is regarded as the ensemble of many glaciers sharing the same region, influenced by a similar climate and organized by certain intrinsic laws. It can be either ‘sensitive’ or ‘steady’. On the basis of the structure of the glacier system and the nature of the equilibrium-line altitudes at the steady state, functional models of a glacier system responding to climate warming were established, using the Kotlyakov–Krenke equation relating annual glacier ablation and mean summer temperature and the glacier system’s median size. The modeling results under the climatic scenarios with a rate of temperature increase of 0.01, 0.03 and 0.05 K a-1 indicate that by the end of this century the glacial area of China will be reduced by –14%, –40%and –60% respectively. However, model results show distinct differences between the sensitive glacier system and the steady glacier system.

scholarly journals Mass-balance variability as a base for interpreting ice-core data

1995 ◽  
Vol 21 ◽  
pp. 201-205
Author(s):  
V. N. Mikhalenko
Keyword(s):  
Mass Balance ◽  
Extreme Values ◽  
Ice Core ◽  
Ice Cores ◽  
Tien Shan ◽  
Glacier Mass Balance ◽  
Similarity Type ◽  
Glacier System ◽  
Point Analysis ◽  
Drilling Site

The spatial extrapolation of data from ice cores depends on the complexity of the glacier system where the drilling site is located. The correlation between net mass balance, b n, of a specific point and of the whole glacier is different for each point. Analysis of net mass balance of Tuyuksu glacier in the Tien Shan, central Asia, confirms that the distribution of mass balance with height is more-or-less constant from year to year except in years with extreme values b n. Two types of “similarity” are described, additive and multiplicative. The “similarity” changes gradually from additive at the peripheral parts of the Tien Shan to multiplicative in the most continental central and eastern parts. Glacier mass-balance fluctuations of the frontal ridges are connected to the oscillations of accumulation and consequently to precipitation. Where the climate is more continental the mass-balance variability depends much more on the melting conditions than on accumulation. For the spatial interpretation of ice-core drilling results, a special analysis of “similarity type” is necessary. It allows the fixing of the spatial borders of the glacier system for which the dhilling site is representative.

scholarly journals Mass Balance Study of a Glacier System from Hydrological Observations in Langtang Valley, Nepal Himalaya

1985 ◽  
Vol 6 ◽  
pp. 318-320
Author(s):  
Tomom Yamaha ◽  
Hideako Motoyama ◽  
Kadcha Bdr. Thapa
Keyword(s):  
Mass Balance ◽  
Monthly Precipitation ◽  
Balance Study ◽  
Nepal Himalaya ◽  
Degree Day ◽  
Glacier System ◽  
Meteorological Observations ◽  
Mass Balance Study ◽  
Glacier Ablation ◽  
Langtang Valley

Hydrological and meteorological observations of river runoff, precipitation and air temperature were conducted 27 August to 26 October 1982, in Langtang Valley, Nepal Himalaya, whereby the mass balance of the glacier system there was estimated. Observed values suggest that (1) all glacier ablation and rainwater in the subwatershed of Langtang Valley drain into the river with the runoff coefficient of 1; (2) ablation of the glacier system can be estimated simply using a degree-day factor of 10 mm/degree-day; and (3) precipitation is considered uniform over the whole watershed. Assuming that the suggested phenomena persist throughout the year, records of monthly precipitation and monthly mean temperature in this valley, indicate that annual accumulation and ablation in the glacier system amount to 2000 ± 200 mm, respectively.

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