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Contemporary glacier systems of continental Eurasia
... The mountain ranges of the Tien Shan are surrounded by densely populated arid lowlands with little summer precipitation, where glacier-fed rivers are the major source for freshwater (Sorg et al. 2012). Despite a dry climate, the Tien Shan holds one of the greatest concentrations of glacial ice in mid-latitude Eurasia (Kotlyakov et al. 2012), while Kyrgyzstan has the largest number of glaciers in the mountain range. Our study region, the Sary-Jaz River Basin ('SJRB'), is the main glacierized region of the Tien-Shan. ...
The water discharge from the heavily glacierized Sary-Jaz River Basin (Eastern Kyrgyzstan) is of high importance for the very arid Tarim Basin located in Xinjiang (north-western China). We investigated glacier changes in the entire Sary-Jaz River Basin, which covers a large part of the Central Tien Shan, for the period from 1990 to 2010 based on Landsat ‘TM’/‘ETM+’data. We found 1310 glaciers (>0.1 km2), which covered 2055 ± 41.1 km2 (∼18% of the entire basin) in 1990. The glaciers shrank by 77.1 ± 57.1 km2 (3.7 ± 2.7%) until 2010. This is considerably lower than in most other ranges of the Tien Shan. The lowest insignificant area loss (−1.5 ± 2.7%) was found in the eastern part of the basin where the largest glaciers and highest peaks are situated. Debris-covered glaciers shrank significantly less than clean-ice glaciers of comparable size. We also identified a few advancing glaciers which show surge characteristics. Climate data from the Tien Shan weather station (3614 m asl.) close to the study region showed no significant long-term trend.
... The TP is characterized by extensive snow cover, glaciers, permafrost, and mountain lakes. About 67% of the plateau is covered by permafrost [Zhou et al., 2000], and the glacier area (about 91,822 km 2 ) [Kotlyakov et al., 2012] over the TP is the third largest on the earth, after the Arctic/Greenland and Antarctic regions (1.7 Â 10 6 -12.3 Â 10 6 km 2 ) [Lemke et al., 2007]. As a unique geological and geographical unit, the TP exerts a profound influence on the East Asian and global climate through mechanical and thermal forcing mechanisms [Kutzbach et al., 1993;Yanai et al., 1992;Zheng and Li, 1999]. ...
The hydrological regimes for the major river basins in the Tibetan
Plateau (TP), including the source regions of the Yellow (UYE), Yangtze
(UYA), Mekong (UM), Salween (US), Brahmaputra (UB), and Indus (UI)
rivers, were investigated through a land surface model and regression
analyses between climate variables and runoff data. A hydrologic
modeling framework was established across the TP to link the Variable
Infiltration Capacity (VIC) land surface hydrology model with a
degree-day glacier-melt scheme (VIC-glacier model) at a 1/12°
× 1/12°. The model performance was evaluated over the upper
basins of the six rivers. The heterogeneity and scarcity of the
meteorological stations are the major limitation for hydrological
modeling over the TP. The relative contributions to streamflow from
rainfall, snowmelt, and glacier melt for the six basins were quantified
via the model framework and simulation. The results suggest that monsoon
precipitation has a dominant role in sustaining seasonal streamflow over
southeastern regions, contributing 65-78% of annual runoff among the
UYE, UYA, UM, US, and UB basins. For the UI, the runoff regime is
largely controlled by the glacier melt and snow cover in spring and
summer. The contribution of glacier runoff is minor for the UYE and UM
(less than 2% of total annual flow), and moderate for the UYA and US
basins (5-7% of yearly flow), while glacier melt makes up about 12% and
48% of annual flow for the UB and UI basins, respectively.
... The TP is characterized by extensive snow cover, glaciers, permafrost, and mountain lakes. About 67% of the plateau is covered by permafrost [Zhou et al., 2000], and the glacier area (about 91,822 km 2 ) [Kotlyakov et al., 2012] over the TP is the third largest on the earth, after the Arctic/Greenland and Antarctic regions (1.7 Â 10 6 –12.3 Â 10 6 km 2 ) [Lemke et al., 2007]. As a unique geological and geographical unit, the TP exerts a profound influence on the East Asian and global climate through mechanical and thermal forcing mechanisms [Kutzbach et al., 1993; Yanai et al., 1992; Zheng and Li, 1999]. ...
The Tibetan plateau (TP) is often considered to be the water tower of Asia being the source of many major Asian rivers such as the Yellow River, Yangtze River, Mekong, Salween, and Brahmaputra. These rivers support hundreds of millions of people downstream. The TP is characterized by a variety of elevations (with the average of above 4000m), large area of snow mountains, glaciers, permafrost, and mountain lakes. Studies have suggested that the surface temperature on the TP has increased about 1.8 degree over the past 50 years, and major climate-induced changes have occurred, such as glacier melting, permafrost degradation, drying of wetlands, and lakes shrinking/ extending. Changes of meteorological factors and the induced changes may have significant impacts on the hydrological cycle and runoff of the source regions of those rivers. Hydrological models provide a useful approach for understanding and evaluating the impact of these changes on runoff. We describe an application of the Variable Infiltration Capacity (VIC) macroscale hydrology model to simulate the land surface water process over the upstream of major rivers in the TP. The VIC model is setup at a 10km spatial resolution over the entire TP. A 10km×10km river network based on 1 km DEM is the basis for routing VIC surface and subsurface runoff to produce simulated streamflow. The modeled water balance is evaluated with streamflow records from the upstream of the Yellow River, Yangtze River, Mekong River, and Brahmaputra. This work is the our step for the climate change impacts assessments on the hydrology and water resources of the major rivers in the Tibetan Plateau.
As the highest peak on the earth, Mt. Qomolangma provides an unparalleled platform to study glacier‐atmosphere interaction. Although glacier surface energy balance (SEB) on Mt. Qomolangma was examined during warm season, relevant knowledge during cold season is still unknown, which prevents a complete understanding of all‐season glacier SEB on it. Based on an in‐situ observation from October 2007 to January 2008, this study presents a cold‐season glacier SEB result at 6,523 m above sea level on Mt. Qomolangma and identifies its atmospheric control. Our results show that the observational period experienced strong winds and deficient clouds. Near‐surface wind speeds usually exceeded 10 m s⁻¹, resulting in a substantial sensible heat transport toward glacier and thus enhancing outgoing longwave radiation, which, under the combined effect of deficient clouds, eventually caused an increase in longwave radiative loss. The large solar zenith angle and relatively high albedo of the glacier surface led to a small absorption of solar irradiance, which, in combination with the strong longwave radiation loss, resulted in a semi‐permanent surface radiative loss. Uncommon over the highly reflective glacier surface, clouds decreased the incident solar radiation more than increased the longwave radiation, demonstrating that the clouds' shading effect surpassed its greenhouse effect. As a vital heat sink, the turbulent latent heat induced an average sublimation rate of 0.8 mm water equivalent per day. This study provides valuable insights into the atmospheric control on the cold‐season glacier‐atmosphere interaction at high altitudes on Mt. Qomolangma when meteorological variables are subject to the westerlies.
Located in the Tibetan Plateau, the upstream regions of the Mekong River (UM) and the Salween River (US) are very sensitive to climate change. The ‘VIC-glacier‘ model, which links a degree-day glacier algorithm with variable infiltration capacity (VIC) model, was employed and the model parameters were calibrated on observed streamflow, glacier mass balance and MODIS snowcover data. Results indicate that: (1) glacier-melt runoff exhibits a significant increase in both areas by the Mann–Kendall test. Snowmelt runoff shows an increasing trend in the UM while the US is characterized by a decreasing tendency. In the UM, the snowmelt runoff peak shifts from June in the baseline period 1964–1990 to May for both the 1990s and 2000s; (2) rainfall runoff was considered as the first dominant factor driving changes of river discharge, which can be responsible for over 84% in total runoff’ trend over the two regions. The glacial runoff illustrates the secondary influence on the total runoff tendency; (3) although the hydrological regime is rain dominated in these two basins, the glacier compensation effect in these regions is obvious, especially in dry years.
The spatial-temporal changes in terrestrial water storage (TWS) over the Tibetan Plateau (TP) and six selected basins during 2003–2014 were analyzed by applying the Gravity Recovery and Climate Experiment data and the extended Variable Infiltration Capacity-glacier model, including the upstream of Yangtze (UYA), Yellow (UYE), Brahmaputra (UB), and Indus river basins and the Inner TP and the Qaidam Basin. The possible causes of TWS changes were investigated from the perspective of surface water balance and TWS components through multisource data and the Variable Infiltration Capacity-glacier model. There was a strong spatial heterogeneity in changes of Gravity Recovery and Climate Experiment TWS in the TP—with apparent mass accumulation in central and northern TP and a sharp decreasing trend in southern and northwestern TP. The TWS changes in the TP were mostly attributed to variations in precipitation and evapotranspiration from the perspective of land-surface water balance. Precipitation played a dominant role on the TWS accumulation in the UYA and UYE, while evapotranspiration had a more important role than precipitation in TWS depletion in the UB. From the perspective of TWS components, the TWS increase in the UYA and UYE was mainly caused by an increase in soil moisture, whereas the decrease in TWS in the UB was mostly due to glacier mass loss. TWS was accumulating from March through August in southeastern TP while from November to April/May in northwestern TP. The seasonal variations of TWS are highly modulated by the large-scale climate system, atmospheric moisture flux, and precipitation regime over the TP.
Himalayan glaciers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some
projections of their future have serious implications for water resources. Most Himalayan glaciers are losing mass at rates
similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding
of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief
within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will
occur soon, although continuing shrinkage outside the Karakoram will increase the seasonality of runoff, affect irrigation
and hydropower, and alter hazards.
Glacier area changes in the Qangtang Plateau are analyzed during 1970–2000 using air photos, relevant photogrammetric maps and satellite images based on the multi-temporal grid method. The results indicate that the melting of glaciers accelerated, only a few of glaciers in an advancing state during 1970–2000 in the whole Qangtang Plateau. However, the glaciers seemed still more stable in the study area than in most areas of western China. We estimate that glacier retreat was likely due to air temperature warming during 1970–2000 in the Qangtang Plateau. Furthermore, the functional model of glacier system is applied to study climate sensitivity of glacier area changes, which indicates that glacier lifespan mainly depends on the heating rate, secondly the precipitation, and precipitation increasing can slow down glacier retreat and make glacier lifespan prolonged.
Osipova, Glaciers (Mysl
- G L D B Dolgushin