Review of climate and cryospheric change in the Tibetan Plateau
TL;DR: In this article, the authors summarize the recent changes observed in climate elements and cryospheric indicators on the Tibetan 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.
Abstract: The Tibetan Plateau (TP), with an average elevation of over 4000 m asl and an area of approximately 2.5 × 10 6 km 2 , 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.
Citations
More filters
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
Cites background from "Review of climate and cryospheric c..."
...Over thepast three decades, the Plateau experienced evident climate changes (Kang et al., 2010), which have changed atmospheric and hydrological cycles and thus reshaped the local environment....
[...]
TL;DR: To reduce the uncertainties and to improve the precision of the predictions of the impacts of climate change and human activities on biogeochemical cycles, efforts should focus on conducting more field observation studies, integrating data within improved models, and developing new knowledge about coupling among carbon, nitrogen, and phosphorus bioge biochemical cycles.
Abstract: With a pace of about twice the observed rate of global warming, the temperature on the Qinghai-Tibetan Plateau (Earth's third pole') has increased by 0.2 degrees C per decade over the past 50years, which results in significant permafrost thawing and glacier retreat. Our review suggested that warming enhanced net primary production and soil respiration, decreased methane (CH4) emissions from wetlands and increased CH4 consumption of meadows, but might increase CH4 emissions from lakes. Warming-induced permafrost thawing and glaciers melting would also result in substantial emission of old carbon dioxide (CO2) and CH4. Nitrous oxide (N2O) emission was not stimulated by warming itself, but might be slightly enhanced by wetting. However, there are many uncertainties in such biogeochemical cycles under climate change. Human activities (e.g. grazing, land cover changes) further modified the biogeochemical cycles and amplified such uncertainties on the plateau. If the projected warming and wetting continues, the future biogeochemical cycles will be more complicated. So facing research in this field is an ongoing challenge of integrating field observations with process-based ecosystem models to predict the impacts of future climate change and human activities at various temporal and spatial scales. To reduce the uncertainties and to improve the precision of the predictions of the impacts of climate change and human activities on biogeochemical cycles, efforts should focus on conducting more field observation studies, integrating data within improved models, and developing new knowledge about coupling among carbon, nitrogen, and phosphorus biogeochemical cycles as well as about the role of microbes in these cycles.
615 citations
Cites background from "Review of climate and cryospheric c..."
...The glacial retreat has caused hydrological changes on the plateau, including increased river discharge and rising lake water levels (Kang et al., 2010)....
[...]
...2b) (Xu et al., 2008; Kang et al., 2010; Li et al., 2010)....
[...]
TL;DR: In this article, the authors established a database of precipitation δ18O and used different models to evaluate the climatic controls of precipitation over the Tibetan Plateau (TP), revealing three distinct domains associated with the influence of the westerlies (northern TP), Indian monsoon (southern TP), and transition in between.
Abstract: The stable oxygen isotope ratio (δ18O) in precipitation is an integrated tracer of atmospheric processes worldwide. Since the 1990s, an intensive effort has been dedicated to studying precipitation isotopic composition at more than 20 stations in the Tibetan Plateau (TP) located at the convergence of air masses between the westerlies and Indian monsoon. In this paper, we establish a database of precipitation δ18O and use different models to evaluate the climatic controls of precipitation δ18O over the TP. The spatial and temporal patterns of precipitation δ18O and their relationships with temperature and precipitation reveal three distinct domains, respectively associated with the influence of the westerlies (northern TP), Indian monsoon (southern TP), and transition in between. Precipitation δ18O in the monsoon domain experiences an abrupt decrease in May and most depletion in August, attributable to the shifting moisture origin between Bay of Bengal (BOB) and southern Indian Ocean. High-resolution atmospheric models capture the spatial and temporal patterns of precipitation δ18O and their relationships with moisture transport from the westerlies and Indian monsoon. Only in the westerlies domain are atmospheric models able to represent the relationships between climate and precipitation δ18O. More significant temperature effect exists when either the westerlies or Indian monsoon is the sole dominant atmospheric process. The observed and simulated altitude-δ18O relationships strongly depend on the season and the domain (Indian monsoon or westerlies). Our results have crucial implications for the interpretation of paleoclimate records and for the application of atmospheric simulations to quantifying paleoclimate and paleo-elevation changes.
604 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
Chinese Academy of Sciences1, University of California, Los Angeles2, University of Gothenburg3, Ohio State University4, University of Maryland, College Park5, Fudan University6, University of California, Santa Barbara7, Peking University8, Japan Agency for Marine-Earth Science and Technology9, University of Tsukuba10, Nanjing University11, San Diego State University12, University of Twente13, National Center for Atmospheric Research14, Texas A&M University15, Pacific Northwest National Laboratory16, Chengdu University of Information Technology17
TL;DR: The Third Pole (TP) is experiencing rapid warming and is currently in its warmest period in the past 2,000 years as mentioned in this paper, and the latest development in multidisciplinary TP research is reviewed in this paper.
Abstract: The Third Pole (TP) is experiencing rapid warming and is currently in its warmest period in the past 2,000 years. This paper reviews the latest development in multidisciplinary TP research ...
530 citations
Cites background from "Review of climate and cryospheric c..."
...Long-term dust variation from ice core records suggested that the TP is also a region suffering from frequent dust storms and blowing dust (Kang et al. 2010b; R. Zhang et al. 2015)....
[...]
...Climate warming brought remarkable changes to the cryosphere on the TP, including glacier retreat and variations in snow amount and cover, as well as increase in temperature, degradation of permafrost, and thickening of the active layer (Kang et al. 2010a ; Bibi et al. 2018)....
[...]
...…general retreat, which breeds and feeds the glacial lakes and leads to their ultimate outbursts (Bolch et al. 2012; Yao et al. 2012b), and made permafrost structure vulnerable, which causes the unstable slopes and erosion and leads to more frequent landslides and debris f lows (Kang et al. 2010a)....
[...]
References
More filters
TL;DR: The NCEP/NCAR 40-yr reanalysis uses a frozen state-of-the-art global data assimilation system and a database as complete as possible, except that the horizontal resolution is T62 (about 210 km) as discussed by the authors.
Abstract: The NCEP and NCAR are cooperating in a project (denoted “reanalysis”) to produce a 40-year record of global analyses of atmospheric fields in support of the needs of the research and climate monitoring communities. This effort involves the recovery of land surface, ship, rawinsonde, pibal, aircraft, satellite, and other data; quality controlling and assimilating these data with a data assimilation system that is kept unchanged over the reanalysis period 1957–96. This eliminates perceived climate jumps associated with changes in the data assimilation system. The NCEP/NCAR 40-yr reanalysis uses a frozen state-of-the-art global data assimilation system and a database as complete as possible. The data assimilation and the model used are identical to the global system implemented operationally at the NCEP on 11 January 1995, except that the horizontal resolution is T62 (about 210 km). The database has been enhanced with many sources of observations not available in real time for operations, provided b...
28,145 citations
11,070 citations
Book•
01 Jan 2007
9,884 citations
European Centre for Medium-Range Weather Forecasts1, Lawrence Livermore National Laboratory2, Chinese Academy of Sciences3, Japan Meteorological Agency4, Met Office5, University of Reading6, Max Planck Society7, Royal Netherlands Meteorological Institute8, National Center for Atmospheric Research9, National Oceanic and Atmospheric Administration10
TL;DR: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions as mentioned in this paper.
Abstract: ERA-40 is a re-analysis of meteorological observations from September 1957 to August 2002 produced by the European Centre for Medium-Range Weather Forecasts (ECMWF) in collaboration with many institutions. The observing system changed considerably over this re-analysis period, with assimilable data provided by a succession of satellite-borne instruments from the 1970s onwards, supplemented by increasing numbers of observations from aircraft, ocean-buoys and other surface platforms, but with a declining number of radiosonde ascents since the late 1980s. The observations used in ERA-40 were accumulated from many sources. The first part of this paper describes the data acquisition and the principal changes in data type and coverage over the period. It also describes the data assimilation system used for ERA-40. This benefited from many of the changes introduced into operational forecasting since the mid-1990s, when the systems used for the 15-year ECMWF re-analysis (ERA-15) and the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) re-analysis were implemented. Several of the improvements are discussed. General aspects of the production of the analyses are also summarized.
A number of results indicative of the overall performance of the data assimilation system, and implicitly of the observing system, are presented and discussed. The comparison of background (short-range) forecasts and analyses with observations, the consistency of the global mass budget, the magnitude of differences between analysis and background fields and the accuracy of medium-range forecasts run from the ERA-40 analyses are illustrated. Several results demonstrate the marked improvement that was made to the observing system for the southern hemisphere in the 1970s, particularly towards the end of the decade. In contrast, the synoptic quality of the analysis for the northern hemisphere is sufficient to provide forecasts that remain skilful well into the medium range for all years. Two particular problems are also examined: excessive precipitation over tropical oceans and a too strong Brewer-Dobson circulation, both of which are pronounced in later years. Several other aspects of the quality of the re-analyses revealed by monitoring and validation studies are summarized. Expectations that the ‘second-generation’ ERA-40 re-analysis would provide products that are better than those from the firstgeneration ERA-15 and NCEP/NCAR re-analyses are found to have been met in most cases. © Royal Meteorological Society, 2005. The contributions of N. A. Rayner and R. W. Saunders are Crown copyright.
7,110 citations
Additional excerpts
...Some researchers also extend use of ERA-40 reanalysis to analyze the climate change in the TP (Frauenfeld et al 2005), indicating that ERA-40 captures the inter-annual variability very well....
[...]
...Using temperature trend magnitudes at 71 surface stations with elevations above 2000 m asl in the eastern and central TP (You et al 2008b) fails to find an elevation dependency in the trends of temperature extremes in the eastern and central TP. Temperature trend magnitudes at the same stations compared with 56 grid points from ‘surface’ NCEP and ERA-40 reanalyses in the TP also show no relationships with elevation (not shown)....
[...]
...We extend the data periods and compare temperatures and their trends from 71 homogenized surface stations (Li et al 2004) with NCEP (Kalnay et al 1996) and ERA-40 (Uppala et al 2005) reanalyses in the eastern and central TP for 1961– 2004 (not shown)....
[...]
...However, no dramatic warming trends are observed in ERA-40....
[...]
...ERA-40 has lower temperature trend magnitudes than surface stations, and NCEP fails to capture warming at all....
[...]