Different glacier status with atmospheric circulations in Tibetan Plateau and surroundings
01 Dec 2013-Vol. 2013
TL;DR: This paper found that the most intensive glacier shrinkage is in the Himalayan region, whereas glacial retreat in the Pamir Plateau region is less apparent, due to changes in atmospheric circulations and precipitation patterns.
Abstract: Glacial melting in the Tibetan Plateau affects the water resources of millions of people. This study finds that—partly owing to changes in atmospheric circulations and precipitation patterns—the most intensive glacier shrinkage is in the Himalayan region, whereas glacial retreat in the Pamir Plateau region is less apparent.
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TL;DR: In this paper, the authors reviewed recent research progress in the climate changes and explored their impacts on the Plateau energy and water cycle, based on which a conceptualmodeltosynthesize these changes was proposed andurgent issues to be explored were summarized.
775 citations
TL;DR: In this paper, the authors used a large-scale, high-resolution cryospheric hydrological model to quantify the upstream hydrologogical regimes of the Indus, Ganges, Brahmaputra, Salween and Mekong rivers and analyzed the impacts of climate change on future water availability in these basins using the latest climate model ensemble.
Abstract: Riv ers originating in the high mountains of Asia are among the most meltwater-dependent river systems on Earth, yet large human populations depend on their resources downstream 1 . Across High Asia’s river basins, there is large variation in the contribution of glacier and snow melt to total runo 2 , which is poorlyquantified.Thelackofunderstandingofthehydrological regimes of High Asia’s rivers is one of the main sources of uncertainty in assessing the regional hydrological impacts of climate change 3 . Here we use a large-scale, high-resolution cryospheric‐hydrological model to quantify the upstream hydrological regimes of the Indus, Ganges, Brahmaputra, Salween and Mekong rivers. Subsequently, we analyse the impacts of climate change on future water availability in these basins using the latest climate model ensemble. Despite large dierences in runo composition and regimes between basins and between tributaries within basins, we project an increase in runo at least until 2050 caused primarily by an increase in precipitation in the upper Ganges, Brahmaputra, Salween and Mekong basins and from accelerated melt in the upper Indus Basin. These findings have immediate consequences for climatechangepolicieswhereatransitiontowardscopingwith intra-annual shifts in water availability is desirable. In general, the climate in the eastern part of the Himalayas is characterized by the East-Asian and Indian monsoon systems, causing the bulk of precipitation to occur during JuneSeptember (Supplementary Fig. 4). The precipitation intensity shows a strong northsouth gradient caused by orographic eects 4 . Precipitation patterns in the Hindu Kush and Karakoram ranges in the west are characterized by westerly and southwesterly flows, causing the precipitation to fall more equally distributed over the year 5 (Supplementary Fig. 4). In the Karakoram, up to two-thirds of the annual high-altitude precipitation occurs during the winter months 6,7 . In addition, basin hypsometry determines the ratio of solid and liquid precipitation within a basin. Solid precipitation can be stored long-term as perennial snow, and ice or short-term as seasonal snow before turning into runo by melting, whereas liquid
774 citations
TL;DR: In this paper, the authors compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008-2011) DEMs derived from SPOT5 stereo imagery.
Abstract: The recent evolution of Pamir-Karakoram-Himalaya (PKH) glaciers, widely acknowledged as valuable high-altitude as well as mid-latitude climatic indicators, remains poorly known. To estimate the region-wide glacier mass balance for 9 study sites spread from the Pamir to the Hengduan Shan (eastern Himalaya), we compared the 2000 Shuttle Radar Topography Mission (SRTM) digital elevation model (DEM) to recent (2008-2011) DEMs derived from SPOT5 stereo imagery. During the last decade, the region-wide glacier mass balances were contrasted with moderate mass losses in the eastern and central Himalaya (-0.22 ± 0.12 m w.e./yr to -0.33 ± 0.14 m w.e./yr) and larger losses in the western Himalaya (-0.45 ± 0.13 m w.e./yr). Recently reported slight mass gain or balanced mass budget of glaciers in the central Karakoram is confirmed for a larger area (+0.10 ± 0.16 m w.e./yr) and also observed for glaciers in the western Pamir (+0.14 ± 0.13 m w.e./yr). Thus, the "Karakoram anomaly" should be renamed the "Pamir-Karakoram anomaly", at least for the last decade. The overall mass balance of PKH glaciers, -0.14 ± 0.08 m w.e./yr, is two to three times less negative than the global average for glaciers distinct from the Greenland and Antarctic ice sheets. Together with recent studies using ICESat and GRACE data, DEM differencing confirms a contrasted pattern of glacier mass change in the PKH during the first decade of the 21st century.
715 citations
TL;DR: The results shed light on the Nyainqentanglha and Pamir glacier mass changes, for which contradictory estimates exist in the literature, and provide crucial information for the calibration of the models used for projections of future glacier response to climatic changes.
Abstract: Glacier mass balances in High Mountain Asia are uncertain. Satellite stereo-imagery allows a spatially resolved estimate for about 92% of the glacierized area and yields a region-wide average of about 16 Gt yr−1 for 2000 to 2016.
614 citations
TL;DR: The Third Pole Environment (TPE) program as mentioned in this paper aims to attract relevant research institutions and academic talents to focus on a theme of water-ice-air-ecosystem-human interactions, to reveal environmental change processes and mechanisms on the Third Pole and their influences on and responses to global changes, and thus to serve for enhancement of human adaptation to the changing environment and realization of human nature harmony.
Abstract: The Tibetan Plateau and surrounding mountains represent one of the largest ice masses of the Earth. The region, referred to by scientists as the Third Pole, covering 5 million km2 with an average elevation of >4000 m and including more than 100,000 km2 of glaciers, is the most sensitive and readily visible indicator of climate change. The area also demonstrates considerable feedbacks to global environmental changes. The unique interactions among the atmosphere, cryosphere, hydrosphere and biosphere on the Third Pole ensure permanent flow of Asia's major rivers, thus significantly influencing social and economic development of China, India, Nepal, Tajikistan, Pakistan, Afghanistan and Bhutan where a fifth of the world's population lives. Like Antarctica and the Arctic, a series of observations and monitoring activities in the Third Pole region have been widely implemented. Yet for a comprehensive understanding of the Third Pole, current observational resources need to be integrated and perfected, and research goals and approaches need to be updated and identified. The Third Pole Environment (TPE) program aims to attract relevant research institutions and academic talents to focus on a theme of ‘water–ice–air–ecosystem–human’ interactions, to reveal environmental change processes and mechanisms on the Third Pole and their influences on and responses to global changes, and thus to serve for enhancement of human adaptation to the changing environment and realization of human–nature harmony.
583 citations
References
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TL;DR: It is shown that meltwater is extremely important in the Indus basin and important for the Brahmaputra basin, but plays only a modest role for the Ganges, Yangtze, and Yellow rivers, indicating a huge difference in the extent to which climate change is predicted to affect water availability and food security.
Abstract: More than 1.4 billion people depend on water from the Indus, Ganges, Brahmaputra, Yangtze, and Yellow rivers. Upstream snow and ice reserves of these basins, important in sustaining seasonal water availability, are likely to be affected substantially by climate change, but to what extent is yet unclear. Here, we show that meltwater is extremely important in the Indus basin and important for the Brahmaputra basin, but plays only a modest role for the Ganges, Yangtze, and Yellow rivers. A huge difference also exists between basins in the extent to which climate change is predicted to affect water availability and food security. The Brahmaputra and Indus basins are most susceptible to reductions of flow, threatening the food security of an estimated 60 million people.
2,754 citations
TL;DR: The contemporary evolution of glaciers in the Himalayan region is reviewed, including those of the less well sampled region of the Karakoram to the Northwest, in order to provide a current, comprehensive picture of how they are changing.
Abstract: 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.
1,561 citations
TL;DR: In this paper, the authors collected monthly surface air temperature data from almost every meteorological station on the Tibetan Plateau (TP) since their establishment, and analyzed the temperature series to show that the main portion of the TP has experienced statistically significant warming since the mid-1950s, especially in winter, but the recent warming in the central and eastern TP did not reach the level of the 1940s warm period until the late 1990s.
Abstract: Adequate knowledge of climatic change over the Tibetan Plateau (TP) with an average elevation of more than 4000 m above sea level (a.s.l.) has been insufficient for a long time owing to the lack of sufficient observational data. In the present study, monthly surface air temperature data were collected from almost every meteorological station on the TP since their establishment. There are 97 stations located above 2000 m a.s.l. on the TP; the longest records at five stations began before the 1930s, but most records date from the mid-1950s. Analyses of the temperature series show that the main portion of the TP has experienced statistically significant warming since the mid-1950s, especially in winter, but the recent warming in the central and eastern TP did not reach the level of the 1940s warm period until the late 1990s. Compared with the Northern Hemisphere and the global average, the warming of the TP occurred early. The linear rates of temperature increase over the TP during the period 1955‐1996 are about 0.16°C:decade for the annual mean and 0.32°C:decade for the winter mean, which exceed those for the Northern Hemisphere and the same latitudinal zone in the same period. Furthermore, there is also a tendency for the warming trend to increase with the elevation in the TP and its surrounding areas. This suggests that the TP is one of the most sensitive areas to respond to global climate change. Copyright © 2000 Royal Meteorological Society.
1,532 citations
TL;DR: In this article, a 50-year NCEP-NCAR reanalysis data reveal remarkably different interannual variability between the Indian summer monsoon (ISM) and western North Pacific summer (WNPSM) in their temporal- spatial structures, relationships to El Nino, and teleconnections with midlatitude circulations.
Abstract: Analyses of 50-yr NCEP-NCAR reanalysis data reveal remarkably different interannual variability between the Indian summer monsoon (ISM) and western North Pacific summer monsoon (WNPSM) in their temporal- spatial structures, relationships to El Nino, and teleconnections with midlatitude circulations. Thus, two circulation indices are necessary, which measure the variability of the ISM and WNPSM, respectively. A weak WNPSM features suppressed convection along 108-208N and enhanced rainfall along the mei-yu/baiu front. So the WNPSM index also provides a measure for the east Asian summer monsoon. An anomalous WNPSM exhibits a prominent meridional coupling among the Australian high, cross-equatorial flows, WNP monsoon trough, WNP subtropical high, east Asian subtropical front, and Okhotsk high. The WNP monsoon has leading spectral peaks at 50 and 16 months, whereas the Indian monsoon displays a primary peak around 30 months. The WNPSM is weak during the decay of an El Nino, whereas the ISM tends to abate when an El Nino develops. Since the late 1970s, the WNPSM has become more variable, but its relationship with El Nino remained steady; in contrast, the ISM has become less variable and its linkage with El Nino has dramatically declined. These contrasting features are in part attributed to the differing processes of monsoon-ocean interaction. Also found is a teleconnection between a suppressed WNPSM and deficient summer rainfall over the Great Plains of the United States. This boreal summer teleconnection is forced by the heat source fluctuation associated with the WNPSM and appears to be established through excitation of Rossby wave trains and perturbation of the jet stream that further excites downstream optimum unstable modes.
956 citations
TL;DR: Glaciers and ice caps, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010, contributing 0.41±0.081 to sea level rise, which agrees well with independent estimates ofSea level rise originating from land ice loss and other terrestrial sources.
Abstract: Satellite measurements of Earth’s gravity field show that the mass loss of glaciers and ice caps contributed to sea level rise by approximately 0.4 millimetres per year between 2003 and 2010. The extent to which mass loss from ice-covered land areas contributes to sea-level rise is not known accurately, in part because previous global estimates use different techniques for glaciers, ice caps and ice sheets. The Gravity Recovery and Climate Experiment (GRACE) satellite has provided monthly measurements of the global gravity field since 2002. Using GRACE data, Jacob et al. assess regional mass loss between 2003 and 2010, and conclude that mass loss from ice-covered land areas contributed almost 1.5 mm per year to the sea-level rise. Estimated mass loss from the high mountains of Asia was negligible, in contrast to some other reports. Glaciers and ice caps (GICs) are important contributors to present-day global mean sea level rise1,2,3,4. Most previous global mass balance estimates for GICs rely on extrapolation of sparse mass balance measurements1,2,4 representing only a small fraction of the GIC area, leaving their overall contribution to sea level rise unclear. Here we show that GICs, excluding the Greenland and Antarctic peripheral GICs, lost mass at a rate of 148 ± 30 Gt yr−1 from January 2003 to December 2010, contributing 0.41 ± 0.08 mm yr−1 to sea level rise. Our results are based on a global, simultaneous inversion of monthly GRACE-derived satellite gravity fields, from which we calculate the mass change over all ice-covered regions greater in area than 100 km2. The GIC rate for 2003–2010 is about 30 per cent smaller than the previous mass balance estimate that most closely matches our study period2. The high mountains of Asia, in particular, show a mass loss of only 4 ± 20 Gt yr−1 for 2003–2010, compared with 47–55 Gt yr−1 in previously published estimates2,5. For completeness, we also estimate that the Greenland and Antarctic ice sheets, including their peripheral GICs, contributed 1.06 ± 0.19 mm yr−1 to sea level rise over the same time period. The total contribution to sea level rise from all ice-covered regions is thus 1.48 ± 0.26 mm −1, which agrees well with independent estimates of sea level rise originating from land ice loss and other terrestrial sources6.
895 citations