25 August 2006, Volume 28 Issue 4
    

  • Select all
    |
  • Glacial Runoff in China: An Evaluation and Prediction for the Future 50 Years
    XIE Zi-chu, WANG Xin, FENG Qing-hua, KANG Er-si, LI Qiao-yuan, CHENG Lei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 457-466. https://doi.org/10.7522/j.issn.1000-0240.2006.0067
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Functional models of glacier system variation are established,on the basis of the structure of glacier system and the nature of the equilibrium line altitudes at the steady state(ELA0),using Kotlyakov-Krenkes’s equation relating annual ablation of glacier and mean summer temperature.The models are applied to study the response of glacial runoff to climatic change.The effect of decreasing air temperature due to rising of ELA0 and reduction of glacial area were taken into account.Based on the data of glacier inventories of China and the models,glacial runoff in China was calculated and possible variation trend of glacial runoff in the future 50 years was evaluated under different temperature rising rates.It is shown that: 1) The total glacial runoff of China was 615.7×108m3 in 1980,and was 659.66×108m3～682.24×108m3 in 2000,7.13%～10.8% more than that in the 1980s,yet the glacial area and volume decreased by 1.07%～1.62% and 1.14%～1.73%,respectively,from 1980 to 2000;2) The glacial runoff will continuously increase on the average from 2000 to 2030,and reach the maximum,about 675.15×108m3～707.91×108m3,in about 2030,with a rate of 9.6～15.0%;3) After 2030,the glacial runoff will decrease,but until 2050 the total glacial runoff will be 8.6～13.6% more than that in the 1980s on the average.So it is a favorable opportunity to utilize the glacial runoff in the years from 2000 to 2050,but it is also the period with high-frequent hazards from glaciers;4) Under the extremely climate warming scenario,0.05 K·a-1,the glacial runoff increasing rate will amount to 26.5% at the runoff climax and the glacial runoff level will be lower than that of the 1980s and 57% of glacial volume will be lost by the end of this century.
  • Degradation of Permafrost in the Da and Xiao Hinggan Mountains,Northeast China,and Preliminary Assessment of Its Trend
    JIN Hui-jun, YU Shao-peng, GUO Dong-xin, LÜ Lan-zhi, LI Ying-wu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 467-476. https://doi.org/10.7522/j.issn.1000-0240.2006.0068
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In the southern margin of permafrost zone of the Eurasian continent,permafrost in the Da and Xiao Hinggan Mountains is warm,thin,thermally unstable and subsequently sensitive to climatic warming.During the past 40 years,permafrost has been degrading as evidenced by deepening active layer,thinning of permafrost,rising ground temperatures,expansion of taliks,and disappearance of permafrost islands.Detailed analyses indicate that climatic warming and sharp reduction of forest coverage during the past century are the general and basic reasons for the degradation of permafrost,and increasing human activities have been accelerating the retreat of permafrost.Based on the close correlations between the southern limit of permafrost(SLP) and decadal average air temperatures,present positions of the SLP are delineated using the multi-year average air temperature isotherms of-1.0~1.0 ℃ during 1999-2000.The SLP would shift northwards upon a projected warming of 1.0~1.5 ℃ during the next 40~50 years,but with significant uneven variations in different parts.
  • Preliminary Study of Mass Balance on the Keqicar Baxi Glacier on the South Slopes of Tianshan Mountains
    ZHANG Yong, LIU Shi-yin, DING Yong-jian, LI Jing, SHANGGUAN Donghui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 477-484. https://doi.org/10.7522/j.issn.1000-0240.2006.0069
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Since the late 1980s,there is a strong signal of climate shift from warm-dry to warm-humid in Northwest China.The mean air temperature of West China from 1987 to 2000 had increased by 0.7℃ as compared with the that from 1961 to 1986.With the rapid rising of air temperature,the annual mean precipitation during the period from 1987 to 2000 increased by 11% in northern Xinjiang and 32% in southern Xinjiang relative to that from 1960 to 1986 within the Tarim basin.In this paper,mass balance of the Keqicar Baxi Glacier in the Tarim River basin,Northwest China,is simulated under the condition of climate change,using a degree-day glacier mass-balance model.The glacier has detailed mass-balance measurement over the period 2003-2005.The modeling results are in good agreement with the measured variations in the mass balance changing with elevation during 2003-2005.The mean mass balance was-494 and-384 mm in the mass balance year of 2003-2004 and 2004-2005,respectively;compared to that in the 1970s,the equilibrium line altitude shifted up about 300 m.It can be seen that,though precipitation increases significantly,there is in the state of strong mass loss on the Keqicar Baxi Glacier due to the air temperature rising significantly.This study aims at providing a method for modelling the mass balance in the glacierised areas of the Tarim River basin,especially,in the non-monitored glacierised areas of Northwest China,as well as to assess the change in the cryosphere due to climate change.
  • Water Resource of Heihe River and Scientific Utilization at Present Phase
    WEI Yu-guang, BAI Fu, ZHANG Tai-ling
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 485-491. https://doi.org/10.7522/j.issn.1000-0240.2006.0070
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The Heihe River is one of longer inland rivers in West China,in the past 30 years,as the continuous increasing of water resource use at the middle and lower reaches of the Heihe River basin has led to less surface water into the Ejin plain and the ecoenvironmental deterioration of the lower reaches.For maintaining the lower oases,since 1992 the water using of the middle and lower reaches of the river basin had been controlled,and a state quantitative allocation scheme of water resources for middle and lower reaches has been put in practice.The research plan of rational using water started after that.This article referenced the recent fruits of the research,recomputing and reevaluating the total water resources,surface water resources,groundwater resources,the current use situation of the surface water and groundwater and the reserves of the Heihe River basin entirely,basing on the truth,the mode of utilizing surface water and groundwater together that the middle region should strength rebuilding water-transport protects,increase the ratio of surface water using,popularize water-saving irrigation projects,develop utilizing benefit of water resources;the lower region should adopt groundwater reasonably,reinforce comprehesive utilizing of surface water and groundwater,improve eco-environmental.This is scientific basis for water utilization at the present phase.
  • The Regional Environment Conditions Reflected by the Mongolian Folk Landscape Patterns in Ejina Banner,Inner Mongolia
    XIAO Sheng-chun, XIAO Hong-lang, XIAO Du-ning, ZHOU Mao-xian
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 492-499. https://doi.org/10.7522/j.issn.1000-0240.2006.0071
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The folk landscape types are the natural and humanistic landscapes,which are named by the idiom of the aborigines based on appreciating,cognizing and evaluating the local environment condition for a long time of practice and live.The folk landscape types are the base of traditional utilization and management of landscapes.It reflected the eco-environment conditions of the time when the folk landscapes were formed.There have a high consistency between the Mongolian folk landscape classification and the traditional one. In this paper,the Mongolian folk landscape types in Ejina Banner of Inner Mongolia Autonomous Region were studied from the early eighteenth century when the Turhut Branch of Mongolian settled down.The changes of environmental pattern in the Ejina delta were outlined by analyzing the folk landscape types of the water bodies,vegetation and sand dunes.The study on the development of the folk landscape types will be help to further research the regional environmental changes.The folk landscapes pattern in Ejina Banner revealed that the landscape types distributed mainly around the Gurinai Lake and the middle reaches of the West-Ejina-River in the last 300 a.This landscapes pattern also showed that the rangeland had temporal continuity.The landscape pattern of water body showed that there had many pools in the middle reaches of the east-and west-Ejina River before the 20th century,besides the two terminal large lakes.Owing to the feeding of the abundant ground water,many large swamps formed in Gurinai and Wentugole Sumu.The ground water table was very high,and water was in high quality in the Ejina Banner.The rapid increase of landscape number of the well for livestock in 20~th century showed there was a worse trend of water environment in the whole region,because the river had changed into the seasonal one,and the river flow could not satisfy local people and their livestock.The landscape pattern of vegetation showed that the riparian forest(Populus euphratica and Elaeagnus Angustifolia forest) and the meadow was the dominative landscapes along the east-and West-Ejina River,and the shrub(Tamarix spp.) land was not the dominative one.And the reed(Phragmites communis)swamp,precarious(Achnatherum splends)meadow and the riparian shrub land of Haloxylon ammodendro was the dominative landscapes in Gurinai and Wentugole Sumu.The vegetation succession in the whole Ejina Banner was in its early stage.The sand dune landscape pattern in Ejina Oasis represents the basal landscape characteristics in the arid desert regions.
  • Impact of Global Warming on the Water Cycle in Xinjiang Region
    FENG Si, HUANG Yun, XU You-peng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 500-505. https://doi.org/10.7522/j.issn.1000-0240.2006.0072
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Xinjiang Uigur Autonomous Region is located in the northwest of China.The special topographic conditions,which is known as "Two basins lie in between three mountains",and the droughty climate create the unique water cycle in the region.With a large number of mountain glaciers in the middle-latitude regions in the world,Xinjiang has an abundant glacial runoff,which is an important factor of the local water cycle and has significant contribution to the local climate and river runoff.As the global climate is getting warmer and warmer,the precipitation,glaciers,runoff of rivers and underground water in Xinjiang Region have undergone great change since the middle 1980s,with an increasing precipitation and a continuously increasing temperature.As a most sensitive sensor of the climatic changes,the glaciers in mountainous regions of Xinjiang Region are thinning and retreating,while the meltwater is increasing.Statistics show that negative mass balance dominates in the Glacier No.1 at river sources of Ürümqi.There is an obvious increase in the average annual runoff in most rivers of Xinjiang Region.Water level increases and surface area multiplies in many lakes and the underground water level rises in some areas. According to the observations at hydrometeorological stations in Xinjiang Region,surface evaporation,which plays a significant role in the water cycle of Xinjiang Region,is decreasing on the whole.So the import of vapor from other countries has to do with an extra precipitation.The acceleration of global water cycle,which is induced by global warming,causes an increase of vapor content in atmosphere.This accounts for the change of precipitation in the past decade in Xinjiang Region. In the model of internal water cycle of Xinjiang Region,one supreme change is the accelerating melt of glaciers,which is a significant contribution to the increase of runoff of rivers,lakes and underground water.The accelerating melt of glaciers is gradually destroying the vulnerable balance of water cycle in a basin and will cause water deficiency in Xinjiang Region consequently and thus aggravate flood disasters. Through the analysis of the change of water cycle in Xinjiang Region in the recent years,this paper concludes that the growth of precipitation in Xinjiang Region is mainly caused by the acceleration of water cycle in the worldwide range.It is revealed from the analysis that the continuously warming global climate will magnificently impact the water resources in Xinjiang Region.
  • Application of Kengyilia thoroldiana to Vegetation Restoration in Gravel-soil-taken Field along the Qinghai-Tibet Railway
    CHEN Gui-chen, ZHOU Guo-ying, SUN Jing, CHEN Zhi-guo, HAN You-ji, LU Xue-feng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 506-511. https://doi.org/10.7522/j.issn.1000-0240.2006.0073
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Aimed at the ecological protection and vegetation restoration in the Qinghai-Tibet railway construction,an experiment of vegetation restoration in the gravel-soil-taken field of alpine steppe along the Qinghai-Tibet Railway was carried out.The application of Kengyilia thoroldiana(Oliv.) J.L.Yang,Yen et Baum to the vegetation restoration in the Tuotuo River area along the Qinghai-Tibet Railway was also discussed in order to provide a scientific basis for vegetation restoration.The results indicated that the gravel-soil-taken field formed in the process of the Qinghai-Tibet railway construction was the secondary bare land,of which the organic matter was 3.31 g·kg-1,and pH value was 8.84.K.thoroldiana is a perennial native plant in drought area of the Tibetan Plateau and characterized by bearing cold and drought,resisting sandstorm and salinity,etc.Of K.thoroldiana Budding ratio is close to 50% and overwintering ratio exceeds 75%.Coverage,overground biomass and underground biomass of plant community reach 41%,(128.16±41.85)g·m-2 and (266.50±95.69) g·m-2 at the second year in the process of restoration.It is obvious that whether for the seeds germination and seeds living through the winter,or for individual development and artificial plant community characteristics,this species hold better applicability with the cold-arid climate and soil environment along the Qinghai-Tibet railway.As long as a corresponding plateau native plant species is chosen and a corresponding technical measure is taken,rapid restoration of vegetation in the permafrost regions along the Qinghai-Tibet Railway could be achieved for a few years.
  • Analysis of the Terrestrial NPP Based on the MODIS in the Source Regions of Yangtze and Yellow Rivers from 2000 to 2004
    GUO Xiao-yin, HE Yong, SHEN Yong-ping, FENG Ding
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 512-518. https://doi.org/10.7522/j.issn.1000-0240.2006.0074
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based on the MOD17A3 data of NASA EOS/MODIS(Terra),the terrestrial NPP in the source regions of Yangtze and Yellow Rivers during 2000 to 2004 is analyzed.The annual NPP of the regions is 82.04 gC·m-2 during the five years,with the maximum of 85.44 gC·m-2 in 2002,and minimum of 78.04 gC·m-2 in 2001.The NPP in the region of Yellow River is higher than that of Yangtze River,and the maximum,exceeding 250 gC·m-2,occurs in the southeastern area of the source region of Yellow Rivers,and the minimum,less than 50 gC·m-2,appears in the northwest of the source region of Yangtze River.The annual NPP is changing from year to year.The annual NPP of alpine meadow is the highest among all vegetations in the regions,and of course,an annual fluctuation appears.Regression analysis shows that temperature is the key factor controlling the terrestrial NPP in the source regions Yangtze and Yellow Rivers.
  • Effect of Antecedent Soil Water Content on the Uncertainty of Hydrological Simulation
    LIU Jin-tao, ZHANG Jia-bao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 519-525. https://doi.org/10.7522/j.issn.1000-0240.2006.0075
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Antecedent soil water content is an important physical factor for hydrological response at a watershed outlet.In hydrological modeling,initial soil water content is calculated by data.In this paper,uncertainty in hydrological simulation is studied by altering antecedent soil water content parameters of the distributed hydrology model.The initial soil water content has prominent influence on the accuracy of hydrological modeling results,especially for the hydrological processes with rare antecedent rainfall.The relationship between observed soil volume water content and antecedent rainfall is given.The correlation coefficient is high between soil volume water content and 15-day antecedent rainfall.The experiential relationship of the observed soil volume water content,antecedent precipitation and the soil moisture parameters is researched in order to provide a way for combining volume water content with soil water parameters in a conceptual model.This relationship facilitates the combination between traditional model and physical features of the basin,which will improve the accuracy and reliability of hydrological simulation.
  • Change of Annual Runoff Distribution in the Headwaters of the Yangtze River
    YAN Hua-yun, YANG Gui-lin, WANG Qing-chun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 526-529. https://doi.org/10.7522/j.issn.1000-0240.2006.0076
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the impact of climate change and increasing the intensity of human activities,the hydrological regime has changed,including annual runoff distribution,which is relating with water resources management and ecological construction.In this paper,the index of unevenness,concentration,and variation have been defined and calculated according to gauge records of runoff in the 1956-2000.Then the change of annual runoff distribution in the headwaters of the Yangtze River is discussed.It is revealed that: 1) the annual runoff distribution in the 1960s was quite similar to that in the 1988s,while in 1970-1976 it was almost the same to that after 1993.2) In the Tuotuohe Station,which locates at the upper reaches,the unevenness,concentration rate,relative variation rate and absolute variation rate are higher than that in the Zhimenda Station.
  • Snowmelt Floods of the Juntanghu River in Xinjiang Region
    WEI Jing-bin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 530-534. https://doi.org/10.7522/j.issn.1000-0240.2006.0077
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Snowmelt floods in Xinjiang Region are frequent.Spring floods are favorable for mitigating the spring drought,but in some condition it can cause calamity.In this paper,using the methods of formation-cause analysis and correlation analysis,some representative snowmelt-flood processes are analyzed,in order to find out the causes of snowmelt floods,the forming mechanism and the flood characteristics,to meet requirements of flood mitigation and flood water utilization.
  • Asynchronous Response of Droughts to ENSO in China
    LU Ai-gang, GE Jian-ping, PANG De-qian, HE Yuan-qing, PANG Hong-xi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 535-542. https://doi.org/10.7522/j.issn.1000-0240.2006.0078
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    The data set of drought from Chinese Planting Information is used to analyze the correlation between the sub-area droughts of China and ENSO index during 19491990.It is found that there is a close relationship between the droughts of China and ENSO index,indicating that the ENSO event influences most China markedly,especially in northern China,northeastern China,southern China,Mongolia and Sinkiang.By comparing the influence asynchrony of ENSO events on various China,a spatial ENSO influence pattern of China is presented: East China is the latest sub area that has a 5-year(not exactly) delay to ENSO and Inner Mongolia is the earliest sub area that has a 3-year(not exactly) advance of the ENSO.Influenced by global warming,ENSO index increases,resulting in a decrease of drought area in China.
  • Water Balance Model of the Mainstream of Tarim River
    CONG Zhen-tao, NI Guang-heng, LEI Zhi-dong, SHI Feng-jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 543-548. https://doi.org/10.7522/j.issn.1000-0240.2006.0079
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A monthly water balance model of the Tarim River mainstream is established based on the analysis of river discharge,evaporation,seepage and overflow.The model input is the river discharge at Alar,and the output items include the discharges of some stations along the mainstream,and evaporation,seepage and overflow of each river section.The model parameters are calibrated with the data from 1981 to 1995,then the model is validated with the data from 1996 to 2002 and the result indicates the model works well.With the model,the water transportation and consumption along the Tarim River mainstream is analyzed,and overflow is identified as the main consumption item.Finally the model is further modified to estimate the effect of the embankment construction.
  • Characteristics of Radiation Balance on the Alpine Wetland in Haibei Prefecture of the Qilian Mountains in Growing Season
    LI Ying-nian, ZHAO Liang, ZHANG Fa-wei, XU Shi-xiao, ZHAO Xin-quan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 549-555. https://doi.org/10.7522/j.issn.1000-0240.2006.0080
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In this paper,radiation balance and changing characteristics on alpine wetland in Haibei Prefecture of the Qilian Mountains were analyzed according to long-term observation data in growing season.The results showed that there were higher total global solar radiation(DR),lower surface reflected radiation(UR) and lower surface effective radiation for the alpine wetland,as well as higher long-wave radiation(DLR),atmospheric inversion radiation(ULR) and net radiation(Rn).Their diurnal and seasonal variations were pronounced.As regards the diurnal variation during growing season(from May to September),the order was DR>Rn>UR>ULR>DLR>ELR,however,as regards the total quantity,the order was ULR>DLR> DR>Rn>UR>ELR,with the values of 4650.6,4225.5,3058.8,2156.2,477.62 and 425.1 MJ·m-2,respectively.In light of monthly variations,the month maxima of ULR,DLR and DR were in July(950.1 MJ·m-2);those of Rn,UR and ELR were in June,May and August.The values of ULR,DLR,DR,Rn,UR and ELR were 980.3,913.1,721.5,554.9,112.1 and 127.4 MJ·m-2,respectively.
  • Impacts of Climate Change on Ecological Environment in Maqu Grassland,Gansu
    WANG Su-ping, SONG Lian-chun, HAN Yong-xiang, FENG Jian-ying
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 556-561. https://doi.org/10.7522/j.issn.1000-0240.2006.0081
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Based the analysis on the climate,ecology and other economic factors in Maqu grassland,the causes of ecology deterioration are discussed.It is found that: 1) The climate has a trend of warming and drying;2) the rapid decrease of runoff of the Yellow River in Maqu has something to do with evaporation and meat yields of flocks and herds,which is an index reflecting anthropic activities,besides, permafrost thawing,temperature rising and precipitation decreasing also play important roles;3) the rapid decrease of grazing yield is associated closely with the dramatically increasing meat yields of flocks and herds,and also results from climate change,such as evaporation increasing and temperature rising.The conclusion is that climate change and the inconsequential anthropic activities result in the ecology deterioration in Maqu grassland.
  • A Simplified Algorithm for Extracting Subpixel Snow Cover Information from MODIS Data
    CAO Yun-gang, LIU Chuang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 562-567. https://doi.org/10.7522/j.issn.1000-0240.2006.0082
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Recently,remote sensing data become the most popular source for acquiring the snow cover information because of easy operation without in-situ investigation.There are many methods to extract snow cover information for various remote sensing data sources,but the results of them are binary images of snow cover.These methods are not suitable for monitoring snow cover in mountain regions.In this study,a simplified algorithm is put forward for MODIS data to get subpixel snow cover information based on the relationship between snow coverage and normalized difference snow index(NDSI),normalized difference vegetation index(NDVI).Finally,a validation for this algorithm using the result from ETM+ data has been carried out.This study indicates that the fraction of snow cover within a MODIS pixel can be estimate by the algorithm effectively.
  • Progress in Studies on the Younger Dryas Event and Its Trigger Mechanisms
    LI Chao-liu, KANG Shi-chang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 568-576. https://doi.org/10.7522/j.issn.1000-0240.2006.0083
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    As the latest abrupt climate event with temperature decrease from the transition of the last glacial period to the Holocene,the Younger Dryas(YD) event that occurred approximately between 12.9 to 11.6 ka BP at north Atlantic is very important on the study of abrupt climate change,while there are still many debates on its trigger site,trigger time,trigger mechanism,as well as whether it is a global event.Furthermore,study on the trigger mechanism of YD event has important value on forecasting future climate change under the background of a continuous global warming at present time.In this paper the current studies on the YD event around the world are reviewed,and the diversities and similarities of its time and intensity in different regions are analyzed.The records of north hemisphere are consistent at some extent,while those of south hemisphere still have many divaricating.Also the possible trigger mechanisms of YD event suggested in recent years are introduced.Generally there are three kinds of mechanisms: the stagnation of thermohaline circulation(THC),the variations of solar radiation and Equatorial Ocean may also contribute to the occurrence of YD event.At last,the regions which need to be further studied and the future focuses on YD have been discussed.
  • Theory of Cosmogenic Nuclide Surface Exposure Dating and Its Applications in Geosciences
    XU Liu-bing, ZHOU Shang-zhe
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 577-585. https://doi.org/10.7522/j.issn.1000-0240.2006.0084
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Cosmogenic nuclide surface exposure dating is a newly developed isotopic dating technique in the past few years.Cosmogenic nuclides are primarily generated by reaction of target nuclei exposed near earth surface and galactic cosmic radiation.The reactions producing cosmogenic nuclides mainly involve spallation,capture of neutrons and muon reaction.The reacting cosmic particles producing nuclides primarily include secondary fast neutrons,thermal neutrons and slow negative muons.Due to the differential special distribution of these reacting particles,the production rates of cosmogenic nuclides at different latitude,altitude and depth are different.The concentration of cosmogenic nuclides is not only constrained by production rates and exposure time,and also closely related to surface erosion.Furthermore,the concentration is affected by geomagnetic intensity, shielding,chemical weathering,and sample geometry as well.These factors affecting cosmogenic nuclide concentration should be calibrated when surface exposure age is calculated.With the progress of the theory and methodology of cosmogenic surface exposure dating,the technique has been widely used in studies of Quaternary glaciations,impact craters,volcanic surfaces,and fault faces.
  • Analyses of the Temperature Fields within an Air Convective Embankment of Crushed Rock Structure along the Qinghai-Tibet Railway
    MA Wei, WU Qing-bai, CHENG Guo-dong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 586-595. https://doi.org/10.7522/j.issn.1000-0240.2006.0085
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    On the base of in-situ monitoring the air convective embankment of crushed rock structure(included the crushed rock embankment, the embankment with crushed rock slope protection and the crushed rock embankment with crushed rock slope protection) along the Qinghai-Tibet Railway,eight monitoring profiles were chosen to analyze the change of ground temperature within an air convective embankment of crushed rock structure in permafrost region with different temperatures(Region I: Tcp≥-0.5 ℃;Region Ⅱ: -1.0 ℃ ≤Tcp<-0.5 ℃;Region Ⅲ: -2.0 ℃ ≤ Tcp<-1.0 ℃;Region Ⅳ: Tcp<-2.0 ℃,where,Tcp is the annual average ground temperature).After 2~3 freezing-thawing circles,the permafrost tables have risen 1.4~5.3 m,showing a positive effect of adjusting and cooling roadbed due to the building of the air convective embankment with crushed rock structure.Meanwhile,it is also revealed that the ground temperature below the permafrost table increases gradually at the initial stage of construction,along with the permafrost table rising.This process has been restrained by the air convective embankment with crushed rock structure.But the restraining effect is different from region to region,depending on temperature.The cooling effect of the air convective embankment with crushed rock structure in Regions Ⅲ and Ⅳ is stronger than that in Regions Ⅱ and Ⅰ.
  • Engineering Techniques for Bridge Works in Permafrost Regions of the Tibetan Plateau
    YU Ju-zhou
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 596-601. https://doi.org/10.7522/j.issn.1000-0240.2006.0086
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Technology measures and engineering techniques for the bridge works in the high and cold regions of the Tibetan Plateau are presented in this paper,which are based on practice and theoretical analyses,analyzing various kinds of circumstances of the plateau,such as high altitude,oxygen lacking,very low temperature and complicated climate,and considering the particularity and complexity of permafrost along the Qinghai-Tibet railway.In permafrost regions of the plateau,the bridge works will change the temperature field,stress field in permafrost and the exchanges of water and heat within permafrost.So,to select a reasonable work season and construction method,and to adopt some compulsory engineering techniques are necessary for reducing heat disturbance in the permafrost regions.
  • Road Icing in Gansu Province and Its Mitigation
    KANG Jun, YU Wen-bing, GUO Ming, LI Guo-yu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 602-606. https://doi.org/10.7522/j.issn.1000-0240.2006.0087
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In Gansu Province there are many areas in cold regions.From the field investigation and analysis,the distribution,formation mechanism and damages of the icing are revealed.The measures for icing controlling are presented.Icing in Gansu Province is mainly located in the Gannan Plateau,Qilian Mountains,Wusao Mountain and Tianshui Prefecture.The icing damage to road is the human activity-induced one in Gansu Province.The average altitude of the Road G213 from Hezuo to Langmusi is about 2 950~3 620 m a.s.l.The maximum freezing depth in this area is 1.42 m.Designers have adopted some different engineering measures to mitigate the road icing in accordance with the engineering conditions,such as raising the embankment,building drainage ditch,culvert,blind ditch and changing the flow direction of water.It is proved that these measures are efficient to road icing controlling.
  • Application of Artificial Neural Network to Studying Salt Expansion Properties of Saline Soil
    SONG Qi-zhuo, CHEN Long-zhu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 607-612. https://doi.org/10.7522/j.issn.1000-0240.2006.0088
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    A non-linear neural network model is established to study the salt expansion properties of saline soil under the function of the five factors,i.e., water content,NaCl concentration,Na2SO4 concentration,initial dry density and overburden pressure of saline soil,based on the documents mentioned in this paper.As compared with the traditional method of quadratic stepwise regression,it shows much more advantages and creditability in solving the problem of the non-linear interaction of multi influencing factors.At the same time,the formula of counting the expansion rate of saline soil under the function of the five factors is updated and coincided the present understanding of the properties of saline soil.
  • A Simulation Test of the Frost Resistance of Cement-Stabilized Gravel in Permafrost Regions
    MA Biao, WANG Bing-gang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 613-617. https://doi.org/10.7522/j.issn.1000-0240.2006.0089
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    There is still not having a uniform testing method to evaluate the frost resistance of the cement-stabilized gravel.Frost-thaw cycle test was done by controlling the sample moisture to simulate the worst humidity condition of the base in the real in permafrost regions.Influence of the frost-thaw cycle times and the sample humidity on the frost resistance index of the base mixture was analyzed.It is found that the frost resistance index of the cement-stabilized gravel gradually decreases with the cycle times,and the humidity has an evident effect on the evaluating result.The results indicated that the full-water frost-thaw test on cement concrete is not feasible to directly evaluate the frost resistance of cement-stabilized gravel in permafrost regions.Controlling the sample moisture to simulate the worst humidity of the base mixture in the real and taking the frost resistance index of the tenth cycle as the evaluating index can well evaluate the frost resistance.The evaluating result is steady and more accordant with the true.
  • Evaluating Method of Environmental Geological Safety along Niubei-Tianshui Expressway
    WU Min-hui, SHEN Yong-ping
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2006, 28(4): 618-622. https://doi.org/10.7522/j.issn.1000-0240.2006.0090
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    On the basis of the field investigation and analysis of the land damaged of geological hazards by remote sensing and historical documental records,role of geology in engineering,hydrologic influences,geologic exploration of engineering sites,mapping,rock mass classifications,geological engineering aspects of underground excavations,slopes are introduced.Complex geological structure,special geographical setting,various rock and soil types,steep landform and frequent rainfall along highway engineering domain of Niubei-Tianshui Section of Tianshui-Baoji Expressway are risk factors for building engineering and mountainous highway environmental geological safety,and should be deeply attention,and evaluation of natural environment and land use safety by GIS and remote sensing are employed in highway building.The engineering geological investigation of highway engineering can be divided as different phases,the working contents and methods of each investigation phase are also put forward.Field mapping of faults,scarps,mass wasting units,Quaternary deposits,fractures,folds,and bedrock is a first step of evaluation on environmental geological safety.Overseeing the on-site hazard data collection and assessment efforts,by analyzing data,it provides accurate and complete onsite hazard recommendations.The results show that there are 61geological disasters potential risk sites in the highway engineering domain of Niubei-Tianshui Section,including 29landslides,25scarps fallings and 7 debris flows.
Copyright © Journal of Glaciology and Geocryology, All Rights Reserved.
Tel: 0931-8260767　
E-mail：edjgg@lzb.ac.cn
Total visitors: 　 Visitors of today: 　 Now online:
Powered by Beijing Magtech Co. Ltd,.