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Processes and modes of permafrost degradation on the Qinghai-Tibet Plateau

Science china Earth sciences 2010年第11期53卷 150-158页

作者： WU JiChun,SHENG Yu,WU QingBai & WEN Zhi State key laboratory of Frozen Soil engineering,{3.,chinese academy of sciences,lanzhou 73.000,china 1. State key laboratory of Frozen Soil engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

Climate warming must lead the mainly air temperature controlled permafrost to *** on the numerical simulation,the process of permafrost degradation can be divided into five stages,i.e.,starting stage,temperature rising stage,zero geothermal gradient stage,talic layers stage,and disappearing stage,according to the shape of ground temperature *** on the Qinghai-Tibet Plateau (QTP) is generally considered a relic from late Pleistocene,and has been degenerating as a whole during *** to spatial-temporal compensation,the present thermal state discrepancy of permafrost in different areas on the QTP may correspond with their degradation *** the QTP,permafrost in the high and middle mountains belongs to temperature rising stage,the permafrost thermal state is transiting from late rising temperature stage to zero geothermal gradient stage that is distributed in the *** that is in a zero gradient stage mainly appears in the high plateau and valley,whereas the transition from zero gradient stage to talic layers stage of permafrost is located in the vicinity of the lower limit of permafrost,and permafrost is disappearing from margin of perennially frozen *** are two modes of perennially frozen ground thawing,thawing from top to bottom and thawing from bottom to top *** the temperature rising stage,when the heat flux in the perennially frozen soil layer is less than that in the unfrozen soil underlying frozen soil layer,the geothermal flux is partly used to thaw the base of permafrost,and permafrost thaws from bottom to *** the decrease of thermal gradient in the perennially frozen ground,the heat that is used to thaw permafrost base increases,and geothermal heat will be entirely consumed to thaw the base of permafrost until the temperature gradient reaches zero thermal gradient *** the other hand,the disappearance of permafrost may be delayed by "thermal offset" and "seas

关键词： Qinghai-Tibet Plateau permafrost degradation process degradation stage degradation mode

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Study of spatial distribution of sandy desertification in North china in recent 10 years

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Science china Earth sciences 2004年第z1期47卷 78-88页

作者： WANG Tao, WU Wei, XUE Xian, SUN Qingwei & CHEN Guangtingkey laboratory of Desert and Desertification, cold and arid regions environmental and engineering research institute, {3., lanzhou 73.000, china Department of Environment engineering, Peking University, Beijing 100871, china chinese Acad Sci Cold & Arid Reg Environm & Engn Res Inst Key Lab Desert & Desertificat Lanzhou 730000 Peoples R China Peking Univ Dept Environm Engn Beijing 100871 Peoples R China

Sandy desertification is a land degradation characterized by wind erosion, mainly resulted from the excessive human activities in arid, semiarid and part of sub-humid regions in North {3.. It is one of main kinds of desertification/land degradation as well as water-soil erosion and salinization in {3.. Rapid and continuous spread of sandy desertification during last 50 years has created a major environmental and socio-economic problem in North {3.. Remote sensing monitored results in 2000 showed that the sandy desertified land area has been 3..57× 104 km2. The area of potential to slightly sandy desertified land is 13.93. 104 km2, moderately land 9.977×104 km2, severely land 7.909 ×104 km2 and very severely land 6.756×104 km2. Sandy desertification mainly occurs in the semi-arid mixed farming-grazing zone and its northern rangeland zone, semi-arid dryland rainfed cropping zone and arid oasis-desert margin zone. The average annually developmental rate of sandy desertified land increased from 2,100 km2 ·a-1 in 1976-1988 to 3.600 km2 · a-1 in 1988-2000. The basic status of sandy desertification in North {3. is 'overall deterioration, while local rehabilitation'. Already achieved rehabilitation results and monitoring assessment show that about 60% of desertified land in North {3. can be restored under the conditions of rational land-use ways and intensity.

关键词： sandy desertified land, spatial distribution, remote sensing monitoring, last 10 years, North china.

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Adaptation Management of Mountain Tourism Service: The Case of the Source regions of the Yangtze and Yellow River

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Journal of Mountain Science 2009年第3期6卷 299-310页

作者： FANG Yiping QIN Dahe DING Yongjian YANG Jianping institute of Mountain Hazards & Environment Chinese Academy of Sciences 610041 Chengdu China cold and arid regions environmental and engineering research institute Chinese Academy of Sciences 730000 Lanzhou China

Mountain areas are often rich in ecological diversity and recreational opportunities. Mountain tourism is thought to be an effective and important means for maintaining and expanding rural economies and, thus, improving the living conditions of rural societies. As mountain tourism service research is a professional field with several disciplines involved, a multi-disciplinary management pIatform is needed and it facilitates participation in sustainable mountain development by diverse stakeholders. With the source regions of the Yangtze and the Yellow River as a case study, this paper presents a conceptual framework for an adaptation management of mountain tourism services according to technical, policy, social and economic dimensions. The framework is based on a vulnerability assessment of mountain ecosystems, and can serve as a reference for the development of tourism service in other mountain areas.

关键词： adaptation management mountain tourism service (MTS) source regions of Yangtze and Yellow Rivers china

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Characteristics of ^(13.)Cs deposition in steppe area

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chinese Science Bulletin 2002年第10期47卷 848-853页

作者： ZHANG Chunlai, ZOU Xueyong,DONG Guangrong, ZHANG Xinbao & QIN Zhilaboratory of Blown Sand Physics and engineering, cold and arid regions environmental and engineering research institute, {3., lanzhou 73.000, china china Center of D laboratory of Blown Sand Physics and engineering Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou China china Center of Desert research at Beijing Normal University Key Laboratory of Environmental Change and Natural Disaster of the Ministry of Education of China Beijing Normal University Beijing China institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu China institute of Modern Physics Chinese Academy of Sciences Lanzhou China

Soil wind erosion in the semiarid steppe area was studied using the 13.Cs tracing technique. Comparisons of 13.Cs deposition characteristics between different soil profiles indicated that slight aeolian activities occurred on sandy grasslands and semi-fixed dunes with erosion/deposition rates of less than 0.108 cm/a, whereas they were intense on semi-shifting dunes with erosion/deposition rates of higher than 1.3. cm/a.

关键词： 13.Cs steppe soil wind erosion.

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On the sand surface stability in the southern part of Gurbantünggüt Desert

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中国科学：地球科学英文版 2005年第6期48卷 778-785页

作者： WANG Xueqin1,2, WANG Tao1, JIANG Jin2 & ZHAO Congju2 1. laboratory of Blown Sand Physics and Desert Environment, cold and arid {3. of environmental and engineering research In-stitute, chinese academy of sciences, lanzhou 73.000, china 2. Xinjiang institute of Ecology and Geography, chinese academy of sciences, Urmqi 83.011, china Correspondence should be addressed to Wang Xueqin 1. laboratory of Blown Sand Physics and Desert Environment Cold and Arid Regions of Environmental and Engineering Research In-stitute Chinese Academy of Sciences 730000 Lanzhou China 2. Xinjiang institute of Ecology and Geography Chinese Academy of Sciences 830011 Urümqi China

Longitudinal dunes are the most widespread dune types in the world sand seas but comprehensive study on the sand surface stability is scarce. The southern part of Gurbantnggt Desert is mainly covered by longitudinal dune in which fixed and semi-fixed dunes occupy over 80% of the total area. Systematic analysis on the climatic conditions, the soil moisture and vegetation distributions, and the sand surface activities showed that the fixed and semi-fixed dunes are in a comprehensive low-energy wind environment. Snow cover and frozen soil provide a good protection to the ground surface in winter. The temporal distribution of precipitation and corresponding variation of temperature create a favorable condition for the desert plants growth, especially for the ephemeral plants. The occurrence of effective winds for sand moving in April to June coincides with the stage of relatively wet sand surface and good vegetation cover, which effectively keep the sand surface stable at the interdune and the plinth of the dunes. Activity sand surface appears only at the crest and the upper part of the sand dunes.

关键词： Gurbantünggüt Desert, longitudinal dune, sand surface stability.

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Development of a chinese land data assimilation system:its progress and prospects

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Progress in Natural Science:Materials International 2007年第8期17卷 881-892页

作者： Li Xin~(1**) Huang Chunlin~1 Che Tao~1 Jin Rui~1 Wang Shugong~l Wang Jiemin~1 Gao Feng~1 Zhang Shuwen~2 Qiu Chongjian~2 Wang Chenghai~2 (1.cold and arid regions environmental and engineering research institute,chinese academy of sciences,lanzhou 73.000,{3. 2.College of Atmospheric sciences,lanzhou University,lanzhou 73.000,{3.) [a]cold and arid regions environmental and engineering research institute Chinese Academy of Sciences Lanzhou China [b]College of Atmospheric sciences Lanzhou University Lanzhou China

The objective of land data assimilation is to merge multi-source observations into the dynamics of land surface model for improving the estimation of land surface *** have developed a land data assimilation system for china's land *** this sys- tem,the Common Land Model and Simple Biosphere Model 2 are used to simulate land surface *** radiative transfer models of thawed and frozen soil,snow,lake,and vegetation are used as observation operators to transfer model predictions into estimated bright- ness temperatures.A Monte-Carlo based sequential filter,the ensemble Kalman filter,is implemented as data assimilation method to inte- grate modeling and *** system is capable of assimilating passive microwave remotely sensed data such as special sensor mi- crowave/imager (SSM/I),TRMM microwave imager (TMI),and advanced microwave scanning radiometer enhanced for EOS (AMSR- E) and the conventional in situ measurements of soil and snow.A spatiotemporally consistent assimilated dataset for soil moisture,soil temperature,snow and frozen soil,with a spatial resolution of 0.25 degree and temporal resolution of one hour,has been *** paper introduces the development of chinese land data assimilation system and the progress made on data assimilation algorithms,land sur- face modeling,microwave remote sensing of land surface hydrological variables,and the preparation of atmospheric forcing *** dis- tinct characteristics and challenges of developing land data assimilation system and the perspectives for future development are also dis- cussed.

关键词： land data assimilation land surface model passive microwave remote sensing Kalman filter

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Losses of Soil Organic Carbon and Nitrogen and Their Mechanisms in the Desertification Process of Sandy Farmlands inHorqin Sandy Land

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Agricultural sciences in china 2003年第8期2卷 890-897页

作者： SU Yong-zhong and ZHAO Ha-lin(cold and arid regions environmental and engineering research institute, chinese academy of sciences,lanzhou 73.000 , P. R. {3.) cold and arid regions environmental and engineering research institute Chinese Academy of Sciences Lanzhou 730000 P.R. China

Soil organic carbon(SOC)and total nitrogen(N)concentrations from bulk soils and soil particle size fractions in the different extent of desertified farmlands(potential, light, medium, severe, and most severe desertified farmlands)were examined to quantitatively elucidate losses of carbon and nitrogen and its mechanisms in the desertification process. Particle size fractions(2 -0.1 mm, 0.1 - 0.05 mm, 3. sandy soils(0 - 15cm depth)of different desertified extent. It was shown that soil physical stability index(St)in most severe desertified farmlands was 5 -7% and St in other farmlands was less than 5 %, which contributed to very low soil organic matter content. This was the intrinsic cause that sandy farmlands in Horqin sandy land was subject to risk of desertification. Desertification resulted in considerable losses of SOC and N. Regression analysis indicated that SOC and N content reduced 0.169 g kg-1 and 0.0215 g kg-1 respectively with one percent loss of soil silt and clay content. Losses of SOC and N were mostly the removal of fine particle size fractions(silt and clay, and a less extent very fine sand)from the farmlands by wind erosion, which were rich in organic matter and nutrients, as well as the depletion of organic C and N associated with coarse particles(>0. 05 mm)in desertification process. The concentrations of C and N associated with sand(2 - 0.1 mm and 0.1 - 0.05 mm)significantly decreased with increase of desertified extent. Silt and clay associated C and N concentrations, however, were less changed, and in contrast, were higher in soils under most severe desertified extent than in soils under potential and severe desertified extent. The percentage of distribution in sand(>0.05 mm)associated C and N significantly increased with increase of desertified extent, suggesting that stability of SOC decreased in the desertification process.

关键词： Farmland desertification Soil organic carbon Total nitrogen Mechanisms of losses

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Physico-chemical Characteristics and environmental Significance of Snow Deposition on Haxilegen Glacier No.51 in Tian Shan,china

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Journal of Mountain Science 2011年第3期8卷 484-494页

作者： DONG Zhiwen LI Zhongqin ZHANG Mingjun WANG Feiteng WU Lihua State key laboratory of cryospheric {3. Cold and Arid Regions Environmental and Engineering Research Institute /Tianshan Glaeiological Station CAS Lanzhou 730000 China College of Geography and Environment Science Northwest Normal University Lanzhou 730070 China Graduate University of chinese academy of sciences Beijing 100049 China

Snow chemistry on the glaciers of alpine regions is a good indicator of atmospheric environmental *** examine snow chemistry in three snowpits at different altitudes on the Haxilegen Glacier No.51,in the Kuitun River source,Tian Shan,china,during July-September 2004 to *** use correlation analysis,factor analysis and sea-salt tracing methods to examine the characteristics and sources of major ions and mineral dust particles in the *** show that mineral dust particles and major ions in the snow pits vary *** the Asian dust period in springtime,the concentration of mineral dust particles and major ions deposited in snow is high,while the concentration is relatively low during the non-dust period of summer and *** may be caused by dust storm activity in central *** order of major ionic concentrations in the snow packs was determined to be Ca2+ > SO42-> NH4+ > NO3.> Cl-> Na+ > Mg2+ > K+.Ca2+ was the dominant cation;SO42- was the dominant *** find,with the exception of NO3.,that the variabilities of ionic concentrations are highly *** show that the glacier region was significantly affected by dust activity and anthropogenic *** major ions,especially Na+,originate from dust sources of central Asia and from the Ocean,transported by the westerly winds.

关键词： Snow chemistry Mineral dust environmental significance Haxilegen glacier No. 51 Tian Shan

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Origin of summer monsoon rainfall identified by δ18O inprecipitation

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Science Bulletin 2005年第23期50卷 2761-2764页

作者： PANG Hongxi1, HE Yuanqing1, 2, ZHANG Zhonglin1, LU Aigang1, GU Juan1 & ZHAO Jingdong1 1. key laboratory of Cryosphere and Environment, cold and {3. Re-gions environmental and engineering research institute, chinese academy of sciences, lanzhou 73.000, china 2. institute of Tibetan Plateau research, chinese academy of sciences, Beijing 100085, china key laboratory of Cryosphere and Environment Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China

A negative correlation between δ 18O in mon-soon precipitation and f, the ratio of precipitable water in monsoon region to that in water source area, is hypothesized. Using the Rayleigh model, a new method for identifying ori-gin of summer monsoon rainfall is developed based on the hypothesis. In order to validate the method, the isotopic data at New Delhi, a typical station in the southwest monsoon region, and Hong Kong, a typical station in the southeast monsoon region, were collected and analyzed for case studies. The case studies indicate that the water source areas of the monsoon rainfall at the two stations identified by the method are accordant with the general atmosphere circulation pat-terns. The method developed in this paper is significantly important for tracing the origin of summer monsoon pre-cipitation.

关键词： monsoon stable isotopes origin of monsoon precipita-tion.

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Influence of Degree-Day Factor Variation on the Mass Balance of Glacier No. 1 at the Headwaters of ürümqi River,china

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Journal of Earth Science 2013年第6期24卷 1008-1022页

作者：崔玉环叶柏生王杰刘友存 State key laboratory of cryospheric {3. Cold and Arid Regions Environment and Engineering Research InstituteChinese Academy of Sciences School of Resources and environmental engineering Anhui University key laboratory of Water Resources and Environment Tianjin Normal University

The degree-day factor （DDF） is a key parameter in the degree-day model, and the varia- tions in DDF have the significant effects on the accuracy of glacier mass balance modeling. In this study, Glacier No. 1 at the headwaters of Uriimqi （-~O）~Z~=） River in china was selected, and the estimated DDF by stakes-observed mass balance and meteorological data from 1983.2006 was used to analyze the spatio-temporal variability of DDF and its influencing factors, such as climate condition, surface fea- ture, and topography. Then, the ablations from the 1980s to 2000s were estimated using the degree-day modei, and the ablation change from the 1980s to 2000s was divided into the changes caused by climate change and by the ice-surface feature. The following results were obtained：（1） The annual change in DDF for snow was not obvious, whereas that for ice increased, and the increasing trend on the lower glacier was more significant than that on the upper glacier because of decreased albedo caused by vari- ations in ice-surface feature; （2） The DDF for ice clearly decreased with altitude by approximately 0.046 and 0.043.mm.＇C-l-d-Lm-1 on the east and west branches, respectively, and the DDF of the west branch was obviously larger than that of the east branch in the same altitude belt; （3. the changes in mass balance in the summers from the 1980s to 2000s were -3.1 and -467 mm on the east and west branches, respectively. Among the total changes, the components directly caused by climate change were -193.and -198 mm, whereas those indirectly caused by ice-surface feature change were -198 and -269 mm on the east and west branches, respectively.

关键词： degree-day factor mass balance,Glacier No. 1 climate change.

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