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Environmental significance of levoglucosan records in a central Tibetan ice core

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Science Bulletin 2019年第2期64卷 122-127页

作者： Chao You tandong yao Chao Xu Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of Sciences

The environmental significance of levoglucosan(LEV) records in Tibetan glacier ice layers on sub-annual to annual scales, in particular their suitability as a specific biomarker for indicating past fire changes, is poorly understood at present. In this work, a continuous LEV record was reconstructed in a central Tibetan ice core for the period 1990–2012. The LEV record was classified into two categories based on its LEV concentrations: background levels and extreme events. Annually-resolved LEV records and background levels in the ice core were strongly correlated with satellite observations of fire occurrence frequency over the northern Indian peninsula between 2003 and 2012, especially for strong fire events during the pre-monsoon season(March–May). In addition, peaks in LEV concentrations may represent extreme fire events in regions around the Tibetan Plateau. LEV records in the ice core reflect a longterm increasing trend in fire background and also an increase in fire extreme events, across the Tibetan Plateau and its surroundings. We therefore conclude that LEV records in Tibetan ice cores can be used as a powerful tool for calibrating and reconstructing past fire changes over subtropical Asia.

关键词： Fire variation Levoglucosan Ice core Tibetan Plateau Subtropical Asia

Preliminary Results on Hydrological and Hydrochemical Features of Kartamak Glacier Area in Mt. Muztag Ata

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Journal of Mountain Science 2007年第1期4卷 77-85页

作者： ZHAO Huabiao yao tandong XU Baiqing Key Laboratory of Cryosphere and Environment CAREERI CAS Lanzhou Gansu 730000 China Institute of Tibetan Plateau Research CAS Bering 100085 China Key Laboratory of Oryosphere and Environment CAREERI CAS Lanzhou Gansu 730000 China

The variations of the meltwater runoff draining from Kartamak Glacier in Mt. Muztag Ata in China were studied by using the measured hydrological data from 1 June to 25 August 2003. The meltwater runoff is mainly affected by ambient temperature and precipitation. Meltwater and precipitation samples were collected from 10 to 23 August 2003. Their pH, EC (electric conductivity) and the major ions (Na^+, K^+, Ca^(2+), Mg^(2+), Cl^-, NO_3^-, SO_~4^(2-)) were determined. pH values showed a positive correlation with EC values for all samples. Meltwater samples were slightly alkaline. Sulfate and calcium were the dominant anion and cation in the measured ions, respectively. All the ion concentrations had inverse relationships with runoff or water level. In order to discuss the origins of dissolved chemical substances in the glacial meltwater, a principal component analysis was carried out. The results showed that water-rock interaction determined the ion components of the meltwater.

关键词： Muztag Ata Kartamak Glacier Meltwater runoff Hydrochemical characteristics

Precipitation variability in central Himalayas and its relation to Northern Hemisphere temperature

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Chinese Science Bulletin 2003年第14期48卷 1480-1482页

作者： DUAN Keqin yao tandong NationalLaboratoryofWesternChina'sEnvironmentalSystems LanzhouUniversity.Lanzhou730000.China

A 149.8-m-long ice core was drilled at theaccumulation area of Dasuopu glacier (28?3′N, 85?3′E, 7100 m a.s.l.) in the central Himalayas in 1997. The ice core was analyzed continuously for stable isotopes (d 18O), cations (Na+, K+, Mg2+, Ca2+) and anions (Cl-, 24SO,-3NO-) throughout the core. Cycles indicated by d 18O, cations and anions were identified and counted as seasonal fluctuations as annual increment from maximum to maximum *** 300-year annual net accumulation from thecore reveals a major precipitation trend for the central Himalayas with an average precipitation 750 mm per year. The trend, separated from the time series, shows a strongcorrelation to global temperature. Generally, as northernglobal temperature increases 0.1℃, the accumulationdecreases about 80mm and vise versa. This may suggests that monsoon precipitation in Himalayas have decreasedcontinuously in past decade as a response to global warming.

关键词：季风降水量喜马拉雅山脉北半球温度全球变暧

Changes in equilibrium-line altitude and implications for glacier evolution in the Asian high mountains in the 21st century

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Science China Earth Sciences 2022年第7期65卷 1308-1316页

作者： Keqin DUAN tandong yao Ninglian WANG Peihong SHI Yali MENG School of Geography and Tourism Shaanxi Normal UniversityXi'an 710062China Institute of Tibetan Plateau Research Chinese Academy of SciencesBeijing 100101China College of Urban and Environmental Sciences Northwest UniversityXi'an 710127China

In the context of global warming,glaciers in the Asian High Mountains(AHMs)are shrinking at an accelerating *** their future change is helpful for understanding the hydrological and climatic effects related to glacier ***,we projected glacier change in the AHMs from 1979 to 2100 under shared socioeconomic pathway(SSP)scenarios from the perspective of temperature,equilibrium-line altitude(ELA),and accumulation *** annual mean temperature in the AHMs increased by 1.26℃ from 1979 to 2014,corresponding to an increase of 210 m in the mean ELA and a decrease of 1.7×10^(4)km^(2) in the glacier accumulation *** the SSP2-4.5(SSP5-8.5)scenario,the annual mean temperature in the AHMs would increase by 2.84℃(3.38℃)in 2040–2060 relative to that in 1850–1900,leading to the mean ELA reaching an elevation of5661 m(5777 m).The accumulation area in the AHMs decreased by 46.3%from 1995 to 2014 and was projected to decrease by60.1%in 2040–***,the annual mean temperature in the AHMs was projected to increase by 3.76℃(6.44℃)in2080–2100 relative to that in 1850–1900,corresponding to the ELA reaching an elevation of 5821 m(6245 m)and the accumulation area decreasing to 1.8×10^(4)km^(2)(0.5×10^(4)km^(2)).These data suggest that the conditions for glacier development will disappear in most of the AHMs,except for extreme high-altitude regions in the Tianshan,Pamir,and Himalaya *** the SSP2-4.5(SSP5-8.5)scenario,when the global mean temperature increases 1.5℃(2℃)above pre-industrial levels,the annual mean temperature will increase by 2.12℃(2.86℃)and the accumulation area will decrease by 15%(48%)in the AHMs compared with that in 1995–***,a 1.5℃ increase in global warming would keep 40%more of the glacial accumulation area(1.5×10^(4)km^(2))in the AHMs compared to a 2℃ increase in global warming.

关键词： Asia High Mountains Glacier Equilibrium-line altitude Accumulation area CMIP6

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Seasonal transition characteristics of the westerly jet: Study based on field observations at an altitude of 6900 m on the Mt. Xixiabangma Dasuopu glacier

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Chinese Science Bulletin 2011年第18期56卷 1912-1920页

作者： LI ShengHai yao tandong TIAN LiDe WANG PengLing Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China State Key Laboratory of Cryosphere Sciences Lanzhou 730000 China Graduate University of Chinese Academy of Sciences Beijing 100049 China National Climate Center China Meteorological Administration Beijing 100081 China

To better understand ultra-high-altitude climate characteristics and their changes, an automatic weather station was installed on August 4, 2005 on the Mt. Xixiabangma Dasuopu glacier (28°23.04′N, 85°43.72′E, 6900 m a.s.l.) in the middle of the Himalayas. Mountain weather conditions were observed continuously and automatically. This paper is the first to publish meteorological data for a whole year for a high-elevation region, and analyze wind direction, wind speed, air temperature, air pressure and humidity. Analysis of the observation data reveals that this region was strongly influenced by the westerly jet from October 10, 2005 to April 21, 2006 and by the Indian monsoon from May to September. The seasonal transitions of the westerly jet were characterized by changes in meteorological elements. In winter, influenced by the westerly jet, the wind speed in the study region was very high and fluctuated violently, gale days were frequent, temperature and air pressure fluctuated dramatically, the diurnal range of temperature decreased and the diurnal range of air pressure increased, relative humidity and specific humidity declined sharply, and air was dry. In summer, influenced by the Indian monsoon, the relative humidity and specific humidity were high. In addition, we analyzed reanalysis data for the location of the automatic weather station. The results confirmed that this region was strongly affected by the westerly jet from October 10, 2005 to April 21, 2006 and the observations that the seasonal transitions of the westerly jet were characterized by changes in meteorological elements.

关键词：高海拔地区西风急流达索普冰川希夏邦马峰季节转换基础研究相对湿度自动气象站

Increasing atmospheric pollution revealed by Pb record of a 7000-m ice core

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Chinese Science Bulletin 1999年第14期44卷 1309-1312页

作者： Wenmian Huo tandong yao Yuefang Li Lanzhou Inst Glaciol & Geocryol Lab Ice Core & Cold Reg Environm Lanzhou 730000 Peoples R China

Concentrations of Pb in Dasuopu ice core in the Qinghai-Tibetan Plateau have been directly measured by ICP-MS at pg/g level. The Pb profile shows a very significant increase in modern times due to anthropogenic input, The use of leaded gasoline in the South Asian countries may be a main source of Pb in this region. The input of Pb to the Dasuopu Glacier is mainly supplied by Indian summer monsoon moisture which traverses the pass at the head of the Dasuopu Glacier.

关键词： Pb pollution Dasuopu ice core.

Impacts of land surface darkening on frozen ground and ecosystems over the Tibetan Plateau

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Science China Earth Sciences 2024年第10期67卷 3213-3225页

作者： Shuchang TANG Tao WANG Dan LIU tandong yao Shilong PIAO Sino-French Institute for Earth System Science College of Urban and Environmental SciencesPeking UniversityBeijing 100101China State Key Laboratory of Tibetan Plateau Earth System Resources and EnvironmentInstitute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Tibetan Plateau(TP) is known as the “Third Pole” of the Earth. Any changes in land surface processes on the TP can have an unneglectable impact on regional and global climate. With the warming and wetting climate, the land surface of the TP saw a darkening trend featured by decreasing surface albedo over the past decades, primarily due to the melting of glaciers, snow,and greening vegetation. Recent studies have investigated the effects of the TP land surface darkening on the field of climate, but these assessments only address one aspect of the feedback loop. How do these darkening-induced climate changes affect the frozen ground and ecosystems on the TP? In this study, we investigated the impact of TP land surface darkening on regional frozen ground and ecosystems using the state-of-the-art land surface model ORCHIDEE-MICT. Our model results show that darkening-induced climate changes on the TP will lead to a reduction in the area of regional frozen ground by 1.1×10~4±0.019×10~4km~2, a deepening of the regional permafrost active layer by 0.06±0.0004 m, and a decrease in the maximum freezing depth of regional seasonal frozen ground by 0.06±0.0016 m compared to the scenario without TP land surface ***, the darkening-induced climate change on the TP will result in an increase in the regional leaf area index and an enhancement in the regional gross primary productivity, ultimately leading to an increase in regional terrestrial carbon stock by0.81±0.001 PgC. This study addresses the remaining piece of the puzzle in the feedback loop of TP land surface darkening, and improves our understanding of interactions across multiple spheres on the TP. The exacerbated regional permafrost degradation and increasing regional terrestrial carbon stock induced by TP land surface darkening should be considered in the development of national ecological security barrier.

关键词： Tibetan Plateau Albedo Land surface darkening Frozen ground Ecosystem

Amplitude of climatic changes in Qinghai-Tibetan Plateau

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Chinese Science Bulletin 2000年第13期45卷 1236-1243页

作者： yao tandong LIU Xiaodong WANG Ninglian SHI Yafeng Lanzhou Institute of Glaciology and Geocryology Chinese Academy of SciencesLanzhou 730000China Lanzhou Institute of Atmospheric Physics Over Highlands Chinese Academy of SciencesLanzhou 73000China

On the basis of ice core and meteorological data from the Qinghai-Tibetan (Q-l) Plateau, this article focuses on the discussion of the problems related to the sensitivity of temporal and spatial changes of the climate in high-altitude regions, particularly in the Q-T Plateau. The features of abrupt climatic changes of the past 100 ka, 2 000 a and recent years indicate that the amplitude of these changes in the Q-T Plateau was obviously larger than that in low-altitude regions. The scope of temperature change above 6 000 m in the Q-T Plateau between glacial and interglacial stages could reach over 10C℃, but only about 4℃ in low-elevation regions close to sea level. During the last 2 000 a, the amplitude of temperature changes at Guliya (over 6 000 m a.s.l.) in the Q-T Plateau reached 7℃, in comparison with 2℃ in eastern China at low altitude. In the present age, apparent differences of climatic warming have been observed in the Q-T Plateau, indicating that the warming in high-elevation regions is

关键词： Qinghai-Tibetan Plateau high elevation region abrupt climatic change amplitude of climatic change climatic sensitivity.

Potentially dangerous glacial lakes across the Tibetan Plateau revealed using a large-scale automated assessment approach

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Science Bulletin 2019年第7期64卷 435-445页

作者： Simon Keith Allen Guoqing Zhang Weicai Wang tandong yao Tobias Bolch Department of Geography University of Zurich Key Laboratory of Tibetan Environmental Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of Sciences School of Geography and Sustainable Development University of St Andrews

Glacial lake outburst floods(GLOFs) are a major concern in the Himalaya and on the Tibetan Plateau(TP),where several disasters occurring over the past century have caused significant loss of life and damage to infrastructure. This study responds directly to the needs of local authorities to provide guidance on the most dangerous glacial lakes across TP where local monitoring and other risk reduction strategies can subsequently be targeted. Specifically, the study aims to establish a first comprehensive prioritisation ranking of lake danger for TP, considering both the likelihood and possible magnitude of any outburst event(hazard), and the exposure of downstream communities. A composite inventory of 1,291 glacial lakes(>0.1 km^2) was derived from recent remote sensing studies, and a fully automated and object assessment scheme was implemented using customised GIS tools. Based on four core determinates of GLOF hazard(lake size, watershed area, topographic potential for ice/rock avalanching, and dam steepness), the scheme accurately distinguishes the high to very high hazard level of 19 out of 20 lakes that have previously generated GLOFs. Notably, 16% of all glacial lakes threaten human settlements, with a hotspot of GLOF danger identified in the central Himalayan counties of Jilong, Nyalam, and Dingri, where the potential trans-boundary threat to communities located downstream in Nepal is also recognised. The results provide an important and object scientific basis for decision-making, and the methodological approach is ideally suited for replication across other mountainous regions where such first-order studies are lacking.

关键词： GLOF Hazard Exposure Danger Tibetan Plateau Himalaya