25 April 2007, Volume 29 Issue 2
    

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  • Impacts of Alpine Ecosystem and Climate Changes on Surface Runoff in the Headwaters of the Yangtze River
    WANG Gen-xu, LI Yuan-shou, WANG Yi-bo, SHEN Yong-ping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 159-168. https://doi.org/10.7522/j.issn.1000-0240.2007.0026
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    In recent 40 years,the alpine ecosystem and permafrost were continuingly degraded under climate warming.Based on the precipitation-runoff yield tests in permafrost regions with varied vegetation coverage,some sub-experiential methods and multi-factor distinguishing method were used in this paper to analyze the impacts of climate,vegetation and permafrost changes on surface runoff.The results show that the annual average runoff decreased by 15.2%,and the runoff with frequency of more than 20% decreased distinctly.However,the frequency of runoff more than 550 m3/s increased.Changes of climate and alpine vegetation coverage contribute to the runoff decrease by 5.8% and 5.5%,respectively.Whereas,the impacts of permafrost and glacier changes on surface runoff are hard to estimate.It is clear that the impacts of climate and vegetation changes on runoff result from an integrated effect that includes permafrost change.In the headwaters,the ecosystem degradation of alpine meadow and swamp meadow was the key factor to result in variation of runoff,precipitation-runoff coefficient decrease and flood frequency increase.Therefore,to protect the alpine meadow and swamp meadow ecosystem from degradation has an important function in water regulation of the Yangtze River.
  • A Contrast of the Ice Formation Time,Ice Formation Zones and the Stratigraphic Profiles of Snow Pits in Different Time of the Glacier No.1 at the Headwaters of the Ürüqi River,Tianshan Mountains
    LI Chuan-jin, LI Zhong-qin, WANG Fei-teng, YOU Xiao-ni
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 169-175. https://doi.org/10.7522/j.issn.1000-0240.2007.0027
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    With the contrastive analyses of the ice formation time,ice formation zones and the stratigraphic snow profiles,the constitution of the profiles,the distribution and the shift of dust layers and the ice layers within snow layers of the Glacier No.1 at the headwaters of the Ürümqi River,Tianshan Mountains,in different time(the 1960s and the 1980s and the beginning of this century),it is found that: since the 1960s,the snow depth on the glacier has decreased,the number and the buried depth of the dust layers and ice layers have decreased,and the profile constitution has changed with the increase of mean density.Ice formation zones have changed also.All the upper limitations of the zones are rising,and the cold percolation zone disappeared and was replaced by percolation zone.The most interesting thing is that the top of the east branch was replaced by an ablation area.With a new method——tracking the marks buried in snow profiles,the ice formation time was determined to be 3.5～4 years.The change of heat state in the snow profiles caused by climate change,especially the temperature rising,is the main reason for the changes.Temperature rising results in more snow melted,and causes the decrease of snow depth,decrease or disappearance of dust layers and ice layers.
  • Spatial and Temporal Variations and Scaling of Precipitation over Northwest China during 1960-2004
    SU Bu-da, WANG Guo-jie, JIANG Tong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 176-182. https://doi.org/10.7522/j.issn.1000-0240.2007.0028
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    Based on precipitation data from 157 meteorological observation stations from 1960 to 2004 in Northwest China(73°~113°E,30°~50°N),Sen’s Slope and Mann-Kendall non-parametric methods are applied to detect the long term trend,and Rotated Empirical Orthogonal Functions analysis is used to get six main spatial modes of normalized precipitation over Northwest China.They are the northeast region,southeast region,northwest region,southwest region,central north region and central south region.Annual precipitation decreased generally from the southeast region to the northwest region.In the last 45 years,decreasing precipitation trend was detected in the southeast region,but a significant increasing precipitation trend was detected in the northwest region.Of note,the decreasing amount was greater than the increasing amount.According to the scaling features obtained by Detrended Fluctuation Analysis,spatial and temporal variations of dynamic mechanism which affect the precipitation process of sub-dividing areas in the last 45 years were analysed.The contributions of regional climatic system and local factors to the precipitation change were quantified.
  • Climate Change and Its Impact on Snow Cover Area in the Tarim River Basin over the Last 45 Years
    XU Chang-chun, CHEN Ya-ning, LI Wei-hong, CHEN Ya-peng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 183-190. https://doi.org/10.7522/j.issn.1000-0240.2007.0029
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    In this paper,the series of annual mean temperature and precipitation at 19 observation stations during 1958-2002 were investigated by non-parametric test in order to find their trends and features of climate change.Based on the investigation,the trend and correlation analyses of snow cover area from 1982 to 2001 were further made in this paper to reveal the effect of climate change on snow.The results showed that both temperature and precipitation had a jump in the mid 1980s.Temperature and precipitation significantly increased in winter and summer,respectively.The SCA of the entire basin showed a slow increasing trend,with a stable increasing in the northern part and the western part and a relatively unstable increasing in the southern part.In the vertical direction,the SCA in the zone below 2 500 m a.s.l increased slowly,and that in the zone above 2 500 m a.s.l decreased.It was easy to be control by precipitation in the zone at low altitude,and to be control by temperature in the zone at high altitude.The zone from 2500 m to 5000 m was most sensitive to climate change.The speeds of snowfall and snowmelt were higher in the 1990s than that in the 1980s.The SCA had positive correlation with precipitation in cold season,but no pronounced correlation with temperature in cold season.
  • Major Ions in Ice Cores and Snowpits from the Himalayas:Temporal and Spatial Variations and Their Sources
    GENG Zhi-xin, HOU Shu-gui, ZHANG Dong-qi, KANG Shi-chang, WANG Ye-tang, LIU Ya-ping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 191-200. https://doi.org/10.7522/j.issn.1000-0240.2007.0030
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    In this paper,the major ion records from three snowpits(two from the East Rongbuk Glacier,situated at 28°01′ N,86°58′ E and 6 500 m a.s.l.,and one from Mount Qowowuyag Snowpit,situated at 28°03′ N,86°39′E and 5 700 m a.s.l.),two low ice cores(one from Nun Kun,situated 33°59′ N,75°58′ E and 4 908 m a.s.l.,and another from Dasuopu Glacier,situated at 28°33′ N,85°44′ E and 7 000 m a.s.l.),and an 80.36 m ice core from East Rongbuk Glacier(situated at 27°59′ N,86°55′ E and 6 450 m a.s.l)are analyzed.It is found that the major ion concentrations are characterized by seasonal change,mainly with high concentration in the non-monsoon seasons and low concentration in the summer monsoon seasons,occasionally with a high Cl-,Na+,and K+ concentrations.The unusual result is presumably due to the import of the regional dust in the summer season,like the dried sedimentation influence from the regional dust.The Na+,K+ and Cl- concentrations from the East Rongbuk Glacier snowpits and the Dasuopu ice core much higher than that from the Mount Qowowuyag Snowpit and the Nun Kun ice core,around several times much higher,which suggests that the Na+,K+ and Cl- concentrations are significantly affected by the local geography.Ammonium concentration of the Mount Qowowuyag Snowpit is much higher than that of other sonwpits and ice cores on the northern slopes.The conclusion can be drawn that the Himalayas notably sets as a barrier against the spread of the ammonium.But the Himalayas appear otherwise for the spread of the dust source ions(like Ca2+ and Mg2+).The air track simulated from the HYSPLIT_4 Model represents a fact that the major ions of the ice cores and snowpits in the winter and spring season in the Himalayas comes mainly from the Thar Desert in south Asia,as well as the dry and rainless plateau regions in west Asia,or more distant,from the Sahara Desert in west African,rather than from Central Asia and the arid and semi-arid Northwest of China as a general knowledge.
  • Glacier Dynamic Models and Their Applicability for the Glaciers in China
    LI Hui-lin, LI Zhong-qin, SHEN Yong-ping, WANG Fei-teng, WANG Wen-bin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 201-208. https://doi.org/10.7522/j.issn.1000-0240.2007.0031
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    Alpine glaciers are sensitive to changes in temperature and precipitation.The shrinkage of alpine glaciers in the twentieth century is on a global scale.For a number of glaciers,the rate of shrinkage appears to have accelerated toward the end of the century.However,the current acceleration of glacier melting apparently has not been predicted by most glacier models.As glacier dynamic models perform satisfactorily for describing physical processes and long-term evolution of glaciers,they likely become a potential tool to reveal the current changes of Alpine glaciers.In this paper,developing history,application conditions,advantages and disadvantages of three dynamic models(frequencyresponse model,factor of profile model,and ice flow model) are discussed.The particular focus is on theirapplicability for the glaciers in China.It indicates that these models may be effective if more data,e.g.glacier mass balance,thickness,surface velocity,and temperature etc.are observed,especially on different kind of glaciers.GIS and remote sensing data can also be employed as supplementary.In addition,as a case study,different models have been applied to Glacier No.1 at headwater of Ürüqi River for its future variation predication.The result indicates that the response time of the glacier is in a magnitude of over one hundred year.The parameter optimizing,modeling processes and all outcomes are presented and discussed in this paper.
  • Variation of the Dryness in the Recent 200a Derived from Tree-Rings Width Records in the East Tianshan Mountains
    WANG Jin-song, LI Jin-bao, CHEN Fa-hu, GOU Xiao-hua, PENG Jian-feng, LIU Pu-xing, JIN Li-ya
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 209-216. https://doi.org/10.7522/j.issn.1000-0240.2007.0032
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    Tree ring width chronologies are constructed by using the tree ring cores of Larix sibirica Ledb.from four sites in eastern Tianshan Mountains.Correlation census and response functions show that the tree ring index closely relates to both precipitation and temperature in March-June(spring to early summer) at forest lower limit.The moisture index(P/T) during spring to early summer is reconstructed by using tree ring width at Barkol area in East Tianshan Mountains in the recent 200 years,with an explanation variance of 42%.Many statistical methods,such as sign test,one order difference sign test and error test,have shown that the reconstructed equation of the moisture index is reliable.It is found that the significant positive correlation between the reconstructed moisture index and the moisture index calculated from the observed data of the nearest meteorological stations,with a coefficient of 0.648.According to the definition of the moisture index,the change of the reconstructed moisture index sequence can be used to describe the change of dryness in the East Tianshan Mountains in the recent 200 years.In this area,there are 6 and 7 remarkable moist and dry periods,respectively.The reconstructed moisture index from March to June in the recent 200 years has stable periods of 11,16,5,8,3 and 32 a.
  • The Impact of Land Use Change on Soil Organic Matter Turnover of Alpine Meadow in the Tibetan Plateau
    TAO Zhen, SHEN Cheng-de, GAO Quan-zhou, SUN Yan-min, YI Wei-xi, LI Ying-nian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 217-225. https://doi.org/10.7522/j.issn.1000-0240.2007.0033
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    High-resolution sampling,measurements of root contents,organic carbon contents and 14C contents,and 14C tracing of the selected disturbed and undisturbed soils in the Haibei Prefecture were made,in order to investigate the effects of land use change on soil organic matter turnover of alpine meadow in the Tibetan Plateau.The results demonstrated that land use change has significant impact on soil C cycle.The increase in soil organic carbon storage is about 29.35% for the disturbed soil after 25-year cultivation;the 14C contents of organic matter in the upper soil horizons of the disturbed soil are lower than those of the undisturbed counterparts.However,organic matter in subsoil horizons(from10 to 50 cm) is relatively enriched in 14C in the disturbed soil.In the undisturbed soil,most of the organic carbon in the surface is resident in "active" C pool with a turnover time of less than 50 years.In the disturbed soil,turnover time significantly increases(to 171-294 a),as compared to its undisturbed counterparts.At deeper depths(below 10 cm in the undisturbed soil,and below 40 cm in the disturbed soil),the organic carbon is dominated by passive C pool with a turnover time greater than 1000 years.The CO2 flux due to organic matter turnover of the soil is 48.7 gC·m-2·a-1 for the disturbed soil and 114 gC·m-2·a-1 for the undisturbed soil.
  • The Chinese Terrestrial NPP Simulation from 1971 to 2000
    HE Yong, DONG Wen-jie, GUO Xiao-yin, JI Jin-jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 226-232. https://doi.org/10.7522/j.issn.1000-0240.2007.0034
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    Based on the meteorological station data we used an Atmosphere-Vegetation Interaction Model(AVIM) that has been validated at regional and global scales to estimate the NPP(net primary production) variation of Chinese terrestrial ecosystems from 1971 to 2000 and its responses to the climate change.The Chinese terrestrial NPP variation from 0 to 987.67 gC·m-2·a-1,averaging from 340.78 to 367.38 gC·m-2·a-1,showing the increase tendency.For the different vegetation the tropical rain forest has the highest NPP values,average is 912.94 gC·m-2·a-1,and the lowest is Sparse shrub,averaging 230.99 gC·m-2·a-1.Our simulation results are consistent with other results of the Chinese terrestrial vegetation.During the 30 years the NPP of vegetation distributing in the southern China,such as tropical rain forest,Broad leaf deciduous trees and broadleaf trees with ground cover decrease and the Needle leaf trees in the northeastern China increases because of the regional climate change.Comparing with the cropland variation under the natural condition owing adopting the modern agriculture technology the actual crop productivity increases significantly from 1971 to 1998,reflecting the human activity influence on the Chinese terrestrial NPP variation.
  • A Preliminary Study of the Glacier Advance in MIS3b in the Western Regions of China
    ZHAO Jing-dong, ZHOU Shang-zhe, LIU Shi-yin, HE Yuan-qing, XU Liu-bing, WANG Jie
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 233-241. https://doi.org/10.7522/j.issn.1000-0240.2007.0035
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    Environmental variations in the Late Pleistocene are hot topics in the research fields of Quaternary environment and global change,including difficulties about the glaciations since the Late Pleistocene.In recent years,the Quaternary glaciations research has entered an accurate dating stage owing to the development and application of dating techniques and a new academic theory that a great glacier advance occurred in marine isotopic stage 3(MIS 3) has been proposed.In the last several years,a research group has carried out further studies in relation to glaciations in Shaluli Mountains which belongs to the Hengduan Mountains,Lenglongling in the eastern segment of the Qilian Mountains and the Ateaoyinake River Valley on the south slopes of the Tomur Peak in the western segment of the Tianshan Mountains,including 3 different areas and 7 sites.ESR dating technique was applied to determine these glacial tills that were collected from above areas and Ge centers in quartz grains were chosen.12 dating results(33~56 ka) dealing with MIS 3 were obtained and ten of these ages are corresponding to MIS 3b(54～44 ka BP).Combining the previous studies and analyzing the climate characteristics of the MIS 3 synthetically,a preliminary conclusion could be drawn: the MIS 3b glacier advance in Shaluli Mountains and Lenglongling was caused by the abundant precipitation carried by the strong monsoon circulation in MIS 3 and cold period of MIS 3b,the glacier advance in the Tianshan Mountains was also a result of the abundant precipitation produced by the unstable westerly and cold period of MIS 3b.The glacial tills formed in MIS 3b were reserved in the three areas.
  • The Elements of the Prophase Atmospheric Indexes Which Influence the Annual Runoff in the Aksu River
    MAO Wei-yi, WANG Tie, JIANG Yuan-an, WANG Jin, LI Hong-de
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 242-249. https://doi.org/10.7522/j.issn.1000-0240.2007.0036
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    The relationships are analyzed between the annual runoff of two embranchments of the Aksu River and all 74 circulation indexes of the former year published by the Climate Diagnostics and Prediction Division of the National Climate Center.Thirty-four sets of initial factor database are constructed separately by moving-correlation method and regression model,and two assembling-regression models are constructed by stepwise regression method.The correlation coefficient is 0.8766 between the measured and simulated annual runoff in the Toxkan River,and 0.8122 in the Kumarik River.There are six atmospheric circulation indexes which have notable correlation with annual runoff of the Toxkan River,one of the two embranchments of the Aksu River.The six indexes belong to six of all the 74 circulation indexes.They are mainly in middle-latitude areas,appearing mainly in February,March,April,and their duration is mainly one month.There are 11 atmospheric indexes which have notable correlation with annual runoff of the Kumarik Rriver,another embranchment of the Aksu River.The 11 indexes belong to seven of all the 74 circulation indexes.They are mainly in low-middle-latitude and high-latitude areas,appearing mainly in August,September and October,and their duration is mainly 2 months.The differences of the spatial-temporal distributions and duration of prophase circulation indexes,which have notable correlation with the annual runoff between the two embranchments of the Aksu River,are obvious.
  • The Conversion Rates of Perturbation Kinetic Energy into Mean Kinetic Energy and Angular Momentum Vortex Transferring in Relation to Snowstorm Processes in Xinjiang Region
    YANG Lian-mei, YANG Tao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 250-257. https://doi.org/10.7522/j.issn.1000-0240.2007.0037
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    Based on the 500 hPa height data of the Northern Hemisphere from 25° to 80° and from May 1995 to April 1999,the daily angular momentum vortex transferring data(RM) and the conversion rate(E)of perturbation kinetic energy into mean kinetic energy are calculated at an interval of five degrees of latitude.The relationship are studied between both the E and RM and the snowstorm weather process in Xinjiang Region.The result shows: E and RM have obvious cycles,seasonal variations and periodicity;the positive high value center of E and low value center of RM have good response to the snowstorm weather process in Xinjiang Region.At the same time the weather process will occur 3 to 6 days later in the region when the positive high value center or low value center appears and the day is regarded as an index date.The forecast accuracy of the snowstorm in Xinjiang Region will be raised when the positive high value center of E and the negative angular momentum vortex transfer center take place simultaneously.
  • Snowmelt Process on the Xiao Dongkemadi Glacier in the Source Region of the Yangtze River and Its Responses to Meteorological Factors
    YANG Jian-ping, DING Yong-jian, YE Baisheng, WANG Qiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 258-264. https://doi.org/10.7522/j.issn.1000-0240.2007.0038
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    Snowmelt was observed in the Xiao Dongkemadi Glacier in the source region of the Yangtze River using flag rod from June 18 to 30 and from July 5 to 9,2005.The results show that snowmelt coincided basically with air temperature variation on the glacier basin from June 18 to 30.Features of snowmelt from July 5 to 9 was that the initial time of snowmelt moved up two hours,from 14:00(from June 18 to 30) to 12:00,that daily average snowmelt amount was about 0.71 mm water equivalent more than that from June 18 to 30,and that the time of maximal snowmelt,appearing at 18:00,was about two hours later than that of maximal air temperature.The profiles of snow pits recorded truly the processes of snow accumulation and ablation.Besides,temperature,snowmelt has close relations to radiation,wind,and other factors.The high the temperature is,the large the snowmelt is.The relation between snowmelt and wind speed is relatively complicated.The amount of snowmelt has correlation only with wind speed at 1.5 m height above land surface.On two-hour time scale,snowmelt was great when wind speed near surface is high.On daily time scale,the correlation of snowmelt and wind speed was good.However,the correlation was reverse from June 18 to 30 and from July 5 to 9.Snow cover is few in the Dongkemadi River basin.Snowmelt water almost cannot generate runoff and then has little impact on the streamflow of Dongkemadi River.This is due to the daily air temperature variation and the alpine meadow vegetation.
  • The State of the Art in Water Resources Utilization in Shiyang River Basin and the Countermeasures for Sustainable Utilization
    XU Wen-hai, ZHANG Yong-ming, CHEN Gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 265-271. https://doi.org/10.7522/j.issn.1000-0240.2007.0039
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    In this paper,the state of the art in the utilization and the problems of exploitation in water resources in the Shiyang River Basin are analyzed.It is believed hat it is imperative to take some measures to correct synthetically the overload of water resources.A resolution is suggested to solve the severe problems of water resources and ecological environment.The resolution is subdivided into two stages.The first stage,a top-priority one,is to rescue water resources and to solve ecological-environmental problems of Shiyang River Basin.According to the ideas of protecting water sources in the south part of basin,developing oasis of the middle part,and controlling sandstorm in the north part,taking comprehensive measures of ecological and environmental conservation in the upper reaches,reforming oasis in the middle reaches,restoring ecological environment in the lower reaches,keeping an ecological environment within a worsening limits as target,centering on improving water-utilization efficiency,taking integrated management of water resources in the river basin,sustainable use of water resources,sustainable development of economy and society,and harmonious coexistence of human being and the nature will come true.
  • The Fluctuation of Admission Fees of Some World Heritage Sites in West China and Its Impact on the Tourism Market——A Case Study of Gansu and Sichuan Provinces
    SHI Hui-chun, YANG Er-jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 272-278. https://doi.org/10.7522/j.issn.1000-0240.2007.0040
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    In 1985,China joined the UNWSCO World Heritage Convention.Up to July of 2006,China had owned 33 World Heritages,include 22 Cultural Heritages,4 Natural Heritages,4 Cultural and Natural Heritages,1 cultural landscape,and 2 Representative of Human Oral and Intangible Heritages.The quantity of China’s World Heritage Sites ranks the third in the world.The admission fees of many China’s World Heritage Sites are increasing.For example,the admission fee of Huangshan Mountain increased 270 times from 1980 to 2002,and that of Mount Emei increased 300 times from 1980 to 2001.In November 30,2004,admission fees hearings about six China’s World Heritage Sites had been held.Since then,most other famous China’s World Heritage Sites held their hearings in order to offer proposals for an increase in admission fees.The admission fees of China’s World Heritage Sites are increasing.This is so frightening that drew attention extensively and aroused controversy intensely,reflecting the problem between world heritage protection and tour management having not been resolved for a long time.As a matter of fact,it is a problem of researching the quantity of tourism marketing under the influence of admission fees change.Because this study is limited in theoretic analysis,a quantitative study is needed in detail.The quantitative study includes the tourism marketing under the influence of admission fee change and the instructional purpose about China’s World Heritage Sites development and management.In this paper,the influence of the tourism marketing on admission fees is discussed,and the influence characteristics of tourist market(including seasonal structure and year structure) is analyzed by the time structure model.It is concluded that raising the admission fees a certain extent can help gaining the goals to limit large quantity of the tourism marketing in a few months,but not in a few years.The following five measures should be taken: establishing a building capacity evaluation system,limiting tickets on sale,time-opening rotation and develop the inactive tourism season,decentralizing tourists quantity of the core area in World Heritage Sites with functional zones,and promoting eco-tourism for reduce the adverse impact and damage to world heritage sites.
  • Microbial Adaptation to the Habitat of Permafrost and Their Responses to Global Change and Engineering Disturbance in Cold Regions: Advances and Prospects
    YANG Si-zhong, JIN Hui-jun, WEI Zhi, JI Yan-jun, HE Rui-xia
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 279-285. https://doi.org/10.7522/j.issn.1000-0240.2007.0041
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    As an extreme habitat,subzero temperatures,composition and availability of nutrients,and freeze-thaw processes in permafrost strongly impact the survival and physiological states,as well as metabolic processes of microorganisms.Microbes in permafrost have successfully adapted to cryogenic stress in morphologic,physiological and biochemical levels.Freeze-thaw processes exert both a direct stress to cells,and indirect restriction to the microbial environment.The microhabitat of microorganisms inside permafrost will be altered as the water-heat balances and dynamics of permafrost being disturbed under the influence of engineering activity.Recently,interferences of infrastructures and pollutants from oil pipeline have affected permafrost and organisms’ dwelling.The fluctuations of microbial numbers and biodiversities were closely related to the epigenetic permafrost and its cryogenesis and the biogeochemical cycles,which may provide proxy records for permafrost development,global climatic and eco-environmental changes.Under a warming climate,microorganisms play important roles in the sequestration,absorption,transportation and emissions of organic carbon and greenhouse gases to the atmosphere in permafrost regions.
  • Diversity of Extremophilic Miroorganisms and Their Applications
    ZHOU Jing, SHENG Hong-mei, AN Li-zhe
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 286-291. https://doi.org/10.7522/j.issn.1000-0240.2007.0042
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    Extremophilic microorganisms are special kinds of beings adapted to extreme environment with isolated evolution relevantly.Their ecology environment is nearly extreme.They have special of structure,physiology traits and molecular evolution mechanisms.Studying the diversity of extremophiles,including thermophiles,psychrophiles,acidophiles,alkaliphiles,barophiles and halophiles,were summarized in this paper.Extremophiles can produce extre-condition enzymes and new biological activated products.Many enzymes have been produced in industrial and applied in practice.
  • Cooling Effect of Crushed Rock Revetment in Permafrost Regions
    SUN Zhi-zhong, MA Wei, LI Dong-qing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 292-298. https://doi.org/10.7522/j.issn.1000-0240.2007.0043
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    During the year of 2003-2005,an experimental embankment was constructed in Beiluhe of the Tibetan Plateau,using the fill material of coarse(7-12 cm) and poorly graded crushed rock on the slopes of embankment on the permafrost foundation with thick ground ice,which should be called the crushed rock revetment embankment(CRRE).The highly permeable CRRE was designed to test the cooling effect of CRRE as compared with conventional embankment.By means of thermistor sensors,ground temperatures in the test sections were monitored.Analyzing the ground temperature data measured in the boreholes within the CRRE and conventional embankments,it is found that crushed rock can effectively reduce annual mean temperature and annual range of temperature on slope surfaces.Comparing with the conventional embankment,one can see that the crushed rock revetment has the effect of heat insulation in summer but is disadvantageous to heat losing in winter.According to the rising of artificial permafrost table and the decreasing of ground temperature range and difference of deformation,the heat stability of CRRE is more than that of the conventional embankment.It will be a long term process for crushed rock revetment to adjust the interior temperature field,so it should be cautious when using the measure in the Qinghai-Tibet Railway.
  • Experimental Study on the Cooling Process of Shading Board Put on an Embankment Slope in Permafrost Regions
    YU Qi-hao, PAN Xi-cai, CHENG Guo-dong, HE Nai-wu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 299-305. https://doi.org/10.7522/j.issn.1000-0240.2007.0044
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    As one of the active cooling measures in permafrost road engineering,shading board(SB) was tested in the Qinghai-Tibet railway and highway.The study about the cooling mechanism of this measure will be helpful for its better use in practice.A series of tests were firstly conducted in laboratory.From the test results it can be found that the cooling effect of the SB mainly consists of two parts: shading the radiation and taking away the heat produced by the secondary radiation.Shading the radiation is most important for relieving the slope surface warming.An indoor test shows that the radiation intensity with SB can decrease by 85.5%.The air convection under a SB can further take away the heat produced by the secondary radiation by the board backside.An indoor test shows that the temperature on the slope surface with SB can be 91% lower than that without SB."Chimney effect" is triggered by the existing SB,then the air velocity under the board greatly increases and the air convective intensity is obviously improved.At the same time,with air in rapid flow under SB,temperature of the slope surface can approximate the environmental air temperature,which is lower than that of the natural ground surface.There exists an optimized height for the SB to keep a maximum of the air flow velocity and quantity,which means that in practice the installed SB height should be taken into account.At the same time,the free flow of the air under the SB should be guaranteed by an unblocked space between the SB and the protected surface.The engineering practices in the Qinghai-Tibet highway showed that SB could reduce the annual average temperature of embankment slope by about 3.2℃ as compared with the common embankment slope,and the annual average temperature under SB is lower than that of the natural ground by about 1.5℃.
  • Nonlinear Analysis of the Temperature Field of the Embankment with Crushed-Rock Revetment and Insulation along the Qinghai-Tibetan Railway
    ZHANG Ming-yi, LI Shuang-yang, GAO Zhi-hua, ZHANG Shu-juan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 306-314. https://doi.org/10.7522/j.issn.1000-0240.2007.0045
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    The embankment with crushed-rock revetment has been widely used in the construction of Qinghai-Tibetan railway.In order to sufficiently protect the underlying permafrost,based on the temperature and geology conditions of the Qinghai-Tibetan railway,a numerical representation of the unsteady two-dimensional continuity,momentum and energy equations of thermal convection for incompressible fluid in porous media is used to analyze and compare temperature characteristics of the embankments with crushed-rock revetment,with and without insulation.The calculated results indicate that in the area where the mean annual air temperature is-4.0℃ and under the assumption that the air temperature will rise by 2.6℃ in the future 50 years,the embankment with crushed-rock revetment and without insulation can protect the underlying permafrost to a certain extent.However,because of the influence of global warming,a residual thawed layer will occur in the middle of roadbed.Furthermore,when the revetment thickness reaches a certain value,the cooling effect of the crushed-rock revetment on the middle part of roadbed can not effectively increase by adding its thickness only.But the embankment with crushed-rock revetment and insulation can effectively reduce the residual thawed layer in roadbed and ensure the stability of permafrost roadbed.Therefore,it is proposed that in warmer permafrost regions,the insulation should be used to increase the cooling effect of embankment with crushed-rock revetment.
  • Heat Transfer Characteristics of the Embankment with Crushed-Rock Slope Protection in Permafrost Regions along the Qinghai-Tibet Railway
    LI Guo-yu, LI Ning, KANG Jia-mei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 315-321. https://doi.org/10.7522/j.issn.1000-0240.2007.0046
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    The embankment with crushed-rock slope protection is a main measure for cooling the permafrost under the Qinghai-Tibet railway.Considering the nocturnal cooling effect on the Qinghai-Tibet railway embankment in summer,numerical analyses about the temperature field,heat flux and thermal flow of the railway embankment with crushed-rock slope protection were conducted.The results show the embankment absorbing heat during daytime and releasing some heat during nighttime under the influence of cool wind.These indicate that the embankment with crushed-rock slope protection has some cooling effect on permafrost during nighttime.In addition,considering the difference of the heat transfer during cold season and warm season,the year-round characteristics of heat transfer was studied.The results show that the embankment keeps in a status of absorbing heat during warm season and releasing heat during cold season.The annual released heat in cold reason is larger than the absorbed heat in warm season,which is helpful for protecting permafrost.
  • Viscoelastic Plastic Model of Frozen Soil and Numerical Calculation Soft Matrix Applied
    LI Dong-wei, WANG Ren-he, LIN Bin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 322-326. https://doi.org/10.7522/j.issn.1000-0240.2007.0047
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    With the development of industry and agriculture in cold regions and spread of the construction technology of artificial freezing,study on the rheology of frozen soil becomes very important.In this paper,Lots of frozen clay specimens are used for the long-term creep tests under single-axial stress states.In order to replace the linear Newtonian body with non-linear Newtonian body,Nishihara Model must be improved.The improved Nishihara Model is proposed to describe the triaxial nonlinear creep constitutive function.Adopting Drucker-Prager(DP) yield model,a soft matrix is derived for numerically calculating.The improved Nishihara Model is added to ADINA FEM,through a secondary developing of finite element program.The improved Nishihara Model is verified by triaxial experiment.The final fitting curves and the theory calculation indicate that the calculated results coincide with the experimental ones very well.The model is able to describe the features of non-linear accelerative creep of frozen soil.
  • The Construction Techniques of Air-Convection Embankment with Crushed Rock in the Permafrost Regions of Qinghai-Tibet Railway
    WANG Gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2007, 29(2): 327-332. https://doi.org/10.7522/j.issn.1000-0240.2007.0048
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    In this paper,through engineering examples,the preferences,construction methods and safeguard measures of the crushed-rock embankment in the permafrost regions of Qinghai-Tibet railway are described in detail.Applying those engineering techniques,at present,the following results are obtained: the ground temperatures on the top and at the bottom of an embankment made of crushed rock are all lower than those of common embankment,so the crushed rock embankment is of great advantage of decreasing embankment temperature,and becomes an effective and initiative engineering measure to protect permafrost;the crushed rock embankment can actively adjust the temperature difference between south slop and north slop,and mitigate the asymmetry of ground temperature;the deformation of the crushed rock embankment is less than that of common embankment.
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