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Kang, S. C.; Wang, F. Y.; Morgenstern, U.; Zhang, Y. L.; Grigholm, B.; Kaspari, S.; Schwikowski, M.; Ren, J. W.; Yao, T. D.; Qin, D. H.; Mayewski, P. A.
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Kang, S.; Wang, F.; Morgenstern, U.; Zhang, Y.; Grigholm, B.; Kaspari, S.; Schwikowski, M.; Ren, J.; Yao, T.; Qin, D.; Mayewski, P. A.
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Lake level and area variations are sensitive to regional climate changes and can be used to indirectly estimate water balances of lakes
. In this study, 10 of the largest lakes in China, ∼1000 km2 or larger, are examined to determine changes in lake level and area derived respectively from ICESat and Landsat data recorded between 2003 and 2009. The time series of lake level and area of Selin Co, Nam Co, and Qinghai Lake in the Tibetan Plateau (TP) and Xingkai Lake in northeastern China exhibit an increasing trend, with Selin Co showing the fastest rise in lake level (0.69 m/a), area (32.59 km2/a), and volume (1.25 km3/a) among the 10 examined lakes. Bosten and Hulun lakes in the arid and semiarid region of northern China show a decline in both lake level and area, with Bosten Lake showing the largest decrease in lake level (−0.43 m/a) and Hulun Lake showing the largest area shrinkage (−35.56 km2/a). However, Dongting, Poyang, Taihu, and Hongze lakes in the mid-lower reaches of the Yangtze River basin present seasonal variability without any apparent tendencies. The lake level and area show strong correlations for Selin Co, Nam Co, Qinghai, Poyang, Hulun, and Bosten lakes (R 2 >0.80) and for Taihu, Hongze, and Xingkai lakes (∼0.70) and weak correlation for East Dongting Lake (0.37). The lake level changes and water volume changes are in very good agreement for all lakes (R 2 > 0.98). Water balances of the 10 lakes are derived on the basis of both lake level and area changes, with Selin Co, Nam Co, Qinghai, and Xingkai lakes showing positive water budgets of 9.08, 4.07, 2.88, and 1.09 km3, respectively. Bosten and Hulun lakes show negative budgets of −3.01 and −4.73 km3, respectively, and the four lakes along the Yangtze River show no obvious variations. Possible explanations for the lake level and area changes in these four lakes are also discussed. This study suggests that satellite remote sensing could serve as a fast and effective tool for estimating lake water balance
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Yao, T.; Thompson, L.; Yang, W.; Yu, W.; Gao, Y.; Guo, X.; Yang, X.; Duan, K.; Zhao, H.; Xu, B.; Pu, J.; Lu, A.; Xiang, Y.; Kattel, D. B.; Joswiak, D.
The Tibetan Plateau and surroundings contain the largest number of glaciers outside the polar regions1
. These glaciers are at the headwaters of many prominent Asian rivers and are largely experiencing shrinkage2, which affects the water discharge of large rivers such as the Indus3, 4. The resulting potential geohazards5, 6 merit a comprehensive study of glacier status in the Tibetan Plateau and surroundings. Here we report on the glacier status over the past 30 years by investigating the glacial retreat of 82 glaciers, area reduction of 7,090 glaciers and mass-balance change of 15 glaciers. Systematic differences in glacier status are apparent from region to region, with the most intensive shrinkage in the Himalayas (excluding the Karakorum) characterized by the greatest reduction in glacial length and area and the most negative mass balance. The shrinkage generally decreases from the Himalayas to the continental interior and is the least in the eastern Pamir, characterized by the least glacial retreat, area reduction and positive mass balance. In addition to rising temperature, decreased precipitation in the Himalayas and increasing precipitation in the eastern Pamir accompanied by different atmospheric circulation patterns is probably driving these systematic differences
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The Tibetan Plateau (TP), with an average elevation of over 4000 m asl and an area of approximately 2
.5 × 106 km2, is the highest and most extensive highland in the world and has been called the 'Third Pole'. The TP exerts a huge influence on regional and global climate through thermal and mechanical forcing mechanisms. Because the TP has the largest cryospheric extent outside the polar region and is the source region of all the large rivers in Asia, it is widely recognized to be the driving force for both regional environmental change and amplification of environmental changes on a global scale. Within China it is recognized as the 'Asian water tower'. In this letter, we summarize the recent changes observed in climate elements and cryospheric indicators on the plateau before discussing current unresolved issues concerning climate change in the TP, including the temporal and spatial components of this change, and the consistency of change as represented by different data sources. Based on meteorological station data, reanalyses and remote sensing, the TP has shown significant warming during the last decades and will continue to warm in the future. While the warming is predominantly caused by increased greenhouse gas emissions, changes in cloud amount, snow-albedo feedback, the Asian brown clouds and land use changes also partly contribute. The cryosphere in the TP is undergoing rapid change, including glacier retreat, inconsistent snow cover change, increasing permafrost temperatures and degradation, and thickening of the active layer. Hydrological processes impacted by glacial retreat have received much attention in recent years. Future attention should be paid to additional perspectives on climate change in the TP, such as the variations of climate extremes, the reliability of reanalyses and more detailed comparisons of reanalyses with surface observations. Spatial issues include the identification of whether an elevational dependency and weekend effect exist, and the identification of spatial contrasts in temperature change, along with their causes. These issues are uncertain because of a lack of reliable data above 5000 m asl
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Xu, B.; Cao, J.; Hansen, J.; Yao, T.; Joswia, D. R.; Wang, N.; Wu, G.; Wang, M.; Zhao, H.; Yang, W.; Liu, X.; He, J.
We find evidence that black soot aerosols deposited on Tibetan glaciers have been a significant contributing factor to observed rapid glacier retreat
. Reduced black soot emissions, in addition to reduced greenhouse gases, may be required to avoid demise of Himalayan glaciers and retain the benefits of glaciers for seasonal fresh water supplies
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