25 December 2004, Volume 26 Issue 6
    

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  • KANG Er-si, LI Xin, ZHANG Ji-shi, HU Xing-lin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 657-667. https://doi.org/10.7522/j.issn.1000-0240.2004.0106
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    In the arid regions of Northwest China, water resources are distributed in various relatively independent inland river basins. They originate from mountain areas, are consumed and distributed in plains, artificial oases at the middle streams and natural oases at the down streams. In the basins of the three inland rivers in the Hexi Corridor of Gansu province, i.e., the Sule River Basin, the Heihe River Basin and the Shiyang River Basin, where water resources are very limited, exploitation and utilization of water resources are mainly concentrated in artificial oases with very vulnerable ecological environment. Over exploitation and utilization of water resources in the artificial oases at the middle streams cause a degradation of ecological environment, and then cause desertification of the natural oases at the down stream of the three inland river. Desertification of the Shiyang River Basin is the most serious among the three basins. The water resource problems related to desertification in the Shiyang River Basin is mainly analyzed and studied in this paper. Competition of exploitation and utilization of water resources among the upper, middle and down streams has enhanced the degradation of natural oases and desertification at the down streams. Therefore, it is necessary to carry out a comprehensive authorized management of basin water resources and rational utilization and allocation of water resources among the upper, middle and down streams and among different sectors and stakeholders. Emphasis of comprehensive management should be put on the water saving irrigation and construction of water saving society in the artificial oases at the middle streams. Sustainable economic and social development, protection of ecological environment, and desertification prevention should be simultaneously integrated.
  • LAN Yong-chao, DING Yong-jian, ZHU Yun-tong, MA Jian-hua, WEI Zhi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 668-673. https://doi.org/10.7522/j.issn.1000-0240.2004.0107
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    Characteristics, possible causes and trends of variations of temperature, precipitation and runoff in the upper Yellow River basin above Tangnag were analyzed, based on the hydrological and meteorological data for about 50-year at some observation stations. The results indicate that the variations of temperature in the basin possess an obvious relationship corresponding with global warming and temperature. Runoff in the upper Yellow River has been decreasing continually since the end of 1980s due to the rising temperature and the decreasing precipitation in the main areas of runoff formation. In the future decades, the runoff in the basin will largely decrease under the conditions of temperature rising obviously and precipitation decreasing greatly, whereas it will increase under the condition of temperature immovability and a great increase in precipitation, and the increase range of runoff may be more than that of precipitation because of the synchronously increasing supply of meltwater from snow, glacier and frozen soils.
  • JIANG Feng-qing, HU Ru-ji, YANG Yue-hui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 674-681. https://doi.org/10.7522/j.issn.1000-0240.2004.0108
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    Based on the flood damaged area, the annual number of the flood-disasters, and the value of financial loss in historical documents from 1950 to 2001, it is found that there is an increasing tendency in flood disasters in Xinjiang in recent 50 years, especially after the 1980s. A non-parameter test (Mann-Kendall test) is employed to survey the abrupt change year for the time series of flooded index, which is derived from the flood-affected area divided by the cultivated land, from 1950 to 2001 and the time series of annual number of flood disasters from 1950 to 1993 in Xinjiang. The years 1986/1987 and 1988 are hence checked out as the abrupt change points with the confidence interval of 95% for the two time series, respectively. Examining the yearly frequency and damages caused by floods indicates a relative increase in loss since the 1980s. It is found that there are three periods when the direct economic loss due to numerous flood catastrophes was different, i.e., a high damaged period from the mid-1980s to the 1990s, a low damaged period from the early 1960s to the early 1980s, and a medium damaged period in 1950s. The reason of abnormal change of the flood disasters in Xinjiang is discussed from viewpoint of climate variability, by correlating the time series of flood-damaged area to the annual precipitation. The analysis shows that there is a linear correlation between the series of the flood damaged area and precipitation in Xinjiang during 1961-1998, with a correlation coefficient of 0.608. The correlation, however, is relatively low with a correlation coefficient of 0.196 for the period 1961-1986 and becomes much close during the period 1987-1998, with a correlation coefficient of 0.68. Evidence shows that the number of heavy rainfall, together with the frequency of floods, has increased in Xinjiang since the 1980s. Therefore, the abrupt increase in flood disasters can be attributed mainly to the increase of precipitation in Xinjiang since the mid 1980s.
  • FENG Qi, LIU Wei, SI Jian-hua, SU Yong-hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 682-690. https://doi.org/10.7522/j.issn.1000-0240.2004.0109
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    Increases in exploitation and utilization of water resources over the last thirty years have led to significant environmental and hydrological degradation of the Tarim River basin. Water of the lower reaches has been seriously compromised. The lower reaches, 300 km in total, have dried up since the 1950s-1970s. The water table decreased from 2~3 m to 4~10 m from 1960 to 1980, and the decreasing rate of the water table is 20 cm per year from 1980 to the present. Populus euphtatica declined by two-thirds and the biomass decreased by one-half from 1958 to 1978 in the basin. From the 1950s to the 1990s, the forest area of P. euphratica and E. angustifolia, the main tree species in the basin, declined by 3820 km2 in the lower reaches in the basin, and the shrub and meadow area declined by 200 km2. The hydrological change results in a marked degradation of aquatic habitats, and causes substantial land desertification. A total of 12300 km2 of desertified lands formed from the 1960s to the 1990s. During the past 30 years, the salt content of the Tarim River increased gradually according to the observation in the Alar Hydrological Station. The maximum salt content was 1.28 g·L-1 in 1960, but reached 4.0 g·L-1 in 1981-1984 and 7.8 g·L-1 in 1998. Based on the present organic carbon content in desertified lands, it is calculated that the total emission of C into atmosphere in the last 30 years reached 112.2 Tg due to the hydrological degradation, of which 28.3% came from the surface layers, 0~1.0 m in depth. Among the factors contributing to these problems, human activities are foremost. Solving these problems will require raising the level of scientific and technological expertise in the monitoring, conservation, protection, and rehabilitation of water resources and associated habitats. Presently, the greatest priority is to expand and improve the conservation and optimal allocation of soil-water resources in the basin.
  • ZHANG Qiang, JIANG Tong, WU Yi-jin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 691-696. https://doi.org/10.7522/j.issn.1000-0240.2004.0110
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    Climatic indicators based on proxy historical flood/drought index series (1470-2003) in the Yangtze River and ENSO (El Nio/Southern Oscillation) index series (1868-2003) are statistically analyzed to detect a long-term variability of the floods/droughts and ENSO events and to identify the tele-connections between ENSO and flood/drought series in the upper reaches of the Yangtze River. The results show that the main flood variation cycle is longer than that of ENSO events. The former shows the periods of 16.69, 5.09 a and 10.47 a (over confidence level of 99%), while the latter shows the periods of 5 a, ~10~12 a and ~10 a. Cross-spectral analysis results indicate the ENSO change and flood/drought variation are significantly correlated at ~5-year period and ~10~12 years period. Therefore, based on the correlation analysis, spectral analysis and cross-spectral analysis, it can be concluded that the response of the floods/droughts along the middle Yangtze River to the effects of ENSO events is not only immediately occurred (about 3 a), but also can be somewhat long-lived (about 5 a or 10~12 a). The results also explicate that the shorter the interval of ENSO event, the sooner the following flood/drought respond and vice versa. Flood could delay if the survival of ENSO event is longer. Eastern Asian summer and winter monsoons are influenced by ENSO through the strength of the subtropical high in the western Pacific region, which can possibly serve as the physical mechanism of the phenomenon mentioned above.
  • MAO Wei-yi, WU Jun, CHEN Chun-yan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 697-704. https://doi.org/10.7522/j.issn.1000-0240.2004.0111
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    Using the data of daily discharge from Shaliguilanke and Shehel Hydrological Gauges of Aksu River and three 0℃ level height data from Aksu, Kuqa and Kashgar Sounding Stations on southern slope of Tianshan Mountains, a relation of 0℃ level height and daily discharge in extreme flooding period of Aksu River, Tarim basin during the summer of 1999 are analyzed. The result shows that daily 0℃ level height data have good correlation with daily discharge of Aksu River, and can be expressed as an exponent function of daily 0℃ level height and daily discharge in 1999 extreme flood The four non-lineal multi-regression forecast models are built from the a relation of 0℃ level height and daily discharge. The statistics of forecast eligibility of excess alertness and excess safety daily discharges and daily peak discharges in different peak discharge stages in Aksu River show good result. The 0℃ level height can be an important factor for forecasting flooding in Aksu River where extending glacier and snow covers have be in headwater region.
  • ZHANG Hong-feng, CHEN Ya-ning, LI Wei-hong, CHEN Ya-peng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 705-712. https://doi.org/10.7522/j.issn.1000-0240.2004.0112
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    The intensive exploitation and utilization of water resources in the upper researches of the Tarim River lead to cutting off of the river from the Daxihaizi Reservoir to the Taitema Nor for 30 years. Without the supply of surface runoff, the groundwater table lowers continuously and vegetation degenerates. Based on the data of stationed plant plots and groundwater table in five sections in the lower reaches of the Tarim River, the features of groundwater table changing and species diversity are analyzed. Before the water conveyance to the lower researches, the depth of groundwater table is below 8 m at Yinsu section, and below 10 m at Yiganbujima section. The coverage of vegetation decreases obviously from upper section to lower section. The distribution features of plant communities in sections of the lower researches of Tarim River are as follow: (1) The community type of Yinsu section and Abudali section is Populus euphratica and Tamarix community. In the constitution of this community, arbor layer is composed of Populus euphratica; shrubbery layer is composed of Tamarix ramosissima, T. hispida, Lycium ruthenicum and Halimodendron halodendron; herbage layer is composed of Glycyrrhiza inflata, Apocynum venetum, Alhagi sparsifolia, Phragmites communis and a litter of Karelinia caspica and Salsola sp. Populus euphratica and Tamarix sp are dominant species among this community. At the angle of vertical structure of community, this community can be divided into arbor layer, shrubbery layer and herbage layer, but relative density and relative coverage of each layer among the whole community are different with each other. At the angle of horizontal structure of community, the distribution of plants is sparse and the distribution of herbage plants takes on fragmentation; the kind and number of species decrease from upper to lower at the lower researches of the Tarim River. (2) The community type of Kardayi section, Alagan section and Yiganbujima section is Populus euphratica and Tamarix community. This community is composed of Populus euphratica, Tamarix accompanied with Lycium ruthenicum and a little of Halimodendron halodendron. Because the groundwater table is too deep to be absorbed by the herbage with shallow root system, there hardly exists herbage except Alhagi sparsifolia with deep root system. Most plants take on degradation. The type of vegetation is mainly desert Tamarix scrub, Tamarix scrub and desert Populus euphratica forest. At the angle of horizontal structure of community, the whole community takes on compound distribution, i.e., three types of Populus euphratica forest, Populus euphratica forest + Tamarix scrub and Tamarix scrub are combined together. (3) The community type of Yiganbujima section and Kaogan section is simple \%Tamarix community. Here Vegetation is more degraded than in other regions for the deeper groundwater table. The vegetation type is desert Tamarix scrub and naked unstable dunes. (4) The region from Kaogan to Taitema Nor has become depositional saline plain, with less vegetation.After 4 times of ecological water conveyance to the lower researches, the groundwater table near the riverbed rises to some extent. The degraded Populus euphratica community and Tamarix community take on rehabilitation. At some washes near the river, Salsola sp, Hexinia polydichotoma and Scorzonera sp grow and thrive. According to an investigation, after 4 times of water conveyance, the kind of herbage species increases at the places where water has overflown, which take on a landscape different from the region away from the river. According to the Grey incidence analysis between species diversity and depth of groundwater, there is close relationship between species diversity and change of depth of groundwater in the lower reaches of the Tarim River: The Grey integrated incidence degrees between species diversity index, including the Shannon-Weiner index, Simpson index, Margalef index, Menhinick index, JSW index and Jsi index, are all above 0.70. The Grey integrated incidence degrees between Simpson index and groundwater level (0.866) is the highest among the species diversity index. The values of the Grey integrated incidence degrees between species diversity and change of groundwater level indicate that groundwater level is the dominant factor in the environmental factors which influenc the change of specie diversity. The aim of ameliorating the ecological environment of the lower reaches of the Tarim River is to increase the coverage of vegetation so as to prevent the environment from deterioration. In view of the effect of water conveyance, the present conveyance along the old river way in the lower reaches of the Tarim River is a way of water conveyance, which can only save Populus euphratica and Tamarix with deep root system. This way has not much significant effect on increasing vegetation coverage and fixing sand. The efficient way is transverse surface conveyance aimed at wakening seed bank, in order to increase species and vegetation coverage for rehabilitating ecological environment.
  • JI Xi-bin, KANG Er-si, ZHAO Wen-zhi, CHEN Ren-sheng, JIN Bo-wen, ZHANG Zhi-hui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 713-719. https://doi.org/10.7522/j.issn.1000-0240.2004.0113
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    Based on Penman-Monteith Equation, the parameters of Shuttleworth-Wallace Model used to calculate the evaporation from sparse crops is modified, a combination equation is derived to calculate the plant transpiration and soil evaporation of agriculture field, and then an one-dimensional soil-vegetation-atmosphere transfer model is employed to simulate the process of soil evaporation, plant transpiration and the total evapotranspiration from irrigational farmlands in the oases in front of the mountains in the Hei River basin during the growing seasons of spring wheat. The modeling relies on the field experiments carried out in the well-irrigated spring wheat lands, and the simulation of evapotranspiration is tested in good fitness with the calculated results from the observation by water balance method. Meanwhile, a sensitivity analysis is also carried out on the net radiation, leaf area index (LAI) and soil water content, to obtain how is their influence to evaporation. Furthermore, the diurnal variation of soil evaporation and crop transpiration shows that two interfaces interact with each other on energy and vapor transition.
  • LIU Pu-xing, GOU Xiao-hua, ZHANG Qi-bin, CHEN Fa-hu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 720-728. https://doi.org/10.7522/j.issn.1000-0240.2004.0114
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    A rich content and system of knowledge, mature research methods in dendrohydrology provide accurate methods for studying long-term hydrologic variability at regional scale. It is valuable in reconstructing hydrology based on tree ring to discern patterns of past long-term nature hydrologic variability and to valid plan and administer water resources. People in the course of hydrology-climate change researches have paid more and more attention to dendrohydrology. In the past several decades, considerable progress has been made in dendrohydrological studies in the world. It turns into another main applied subject following dendroclimatology. Based on scientific understanding to its concept and connotation, the methodology of hydrologic reconstruction with tree ring is introduced. The paper reviews the content and advances from four aspects: streamflow reconstruction, reconstruction of dry and flood, reconstruction precipitation and other reconstructions such as water level of lakes and bogs and so on. The development trend in this field is also briefly summarized.
  • ZHANG Zhong-lin, HE Yuan-qing, PANG Hong-xi, LU Ai-gang, GU Juan
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 729-735. https://doi.org/10.7522/j.issn.1000-0240.2004.0115
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    Using the data of Chinese Glacier Inventory and NCEP/NCAR, the vapor flux and the atmospheric circulations around China, distribution features of glaciers and precipitation patterns in China have been analyzed in this paper. There are various atmospheric circulations controlling the climate in China. Accordingly, the glacier distribution in different regions has been influenced by different climatic conditions. The westerly dominates mainly in Northwest China in the scope of 30° and 100° and carries vapors to the glaciers in this region. Southwest China, east to the Hengduan Mountains and north to 30°, is mainly controlled by the southwest monsoon, which brings moisture to the glaciers there from Indian Ocean, Arabian Sea and the Bay of Bengal. Southeast China, west to the Hengduan Mountains, is influenced mainly by southeast monsoon, where the vapors to the glaciers, especially to those glaciers on the east slopes of the Hengduan Mountains, come from Pacific Ocean and the South China Sea. Both southwest monsoon and southeast monsoon dominate jointly in the Hengduan Mountains, the Nyainqêntanglha Range and the eastern Tibetan Plateau, where the moistures to the glaciers are mainly from the Bay of Bengal and South China Sea. There is a very good accordance between the variations of the accumulation rates and the local summer monsoon indices in various regions.
  • ZHANG Tang-tang, REN Jia-wen, KANG Shi-chang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 736-739. https://doi.org/10.7522/j.issn.1000-0240.2004.0116
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    During the Sino-American Glacier Expedition to Nyainqêntanglha Range in 1999 and 2003, the Lanong Glacier was investigated and its terminus location was measured by means of GPS technique. Compared with the map that was aerial photographed in 1970s, it is found that the glacier has retreated 285 m from 1970 to 1999, and 13 m from 1999 to 2003, equivalent to a retreat speed of 9.8 m·a-1and 3.25 m·a-1respectively. These suggest that climate there has mainly been in warming since the 20 century. Because the response of glaciers to climate change has a retardation, the Lanong Glacier retreat will continue in the future due to climate still being warming in recent years.
  • ZHANG Yu, LIU Gui-min, MA Hai-yan, WANG Gen-xu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 740-746. https://doi.org/10.7522/j.issn.1000-0240.2004.0117
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    Land-use and land-cover change is one of the important issues in global change research because it is not only the significant component but also the major reason of global change. Based on a certain division of land-use and the TM data of the Heihe River basin from 1987 to 2000, and from the changing amplitude, changing rate and spatial dynamic degree of land-use and land-cover, in this paper, the changing characteristics of land-use and land-cover in the Heihe River basin are analyzed, and a contrast among the upper reaches, the middle reaches and the lower reaches is made. In this course, nine quantity indexes that aim at a single land-use type, area land-use type and area integrated land-use type, respectively, are used. From the study, the following conclusions are drawn: (1) The land-use and land-cover change are very serious in the whole river basin, especially in the middle reaches. The plantation, building land, water area and grassplot change most markedly. (2) The plantation, building land and desert land in the upper reaches are changing most rapidly. The plantation, building land, water area and other lands that are difficult to be used are also changing very quick. However, in the middle reaches lands change relatively slowly. (3) Plantation, building land and those lands difficult to be used are relatively stationary, but other lands change quite actively. So, the land-use and land-cover change is very complicated in the middle reaches of the Heihe River.
  • LI Xiao-yu, WU Kai-tuo, XIAO Du-ning
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 747-754. https://doi.org/10.7522/j.issn.1000-0240.2004.0118
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    Using GIS and landscape structure analysis program FRAGSTATES, based on the TM image of Shiyang River watershed in 1986 and 2000, in this paper the landscape metrics of the watershed in 1986 and 2000 are calculated and analyzed at class metrics level and landscape metrics level respectively. The transformation matrix of the landscape mosaics is also got, which is the base for spatial change analysis of the landscape patterns. The results show that: although the landscape patterns have changed at the whole watershed level, the landscape is at a relatively stable status; but at the typical oases level, landscape patterns have changed remarkably. In Minqin oasis, desertification develops evidently, as a result the area of farmland and sandy land increases observably, and the area of woodland and grassland decreases markedly. The sequent of these changes is fragmentation of landscape, simplification of landscape mosaics and decrease in landscape diversity. The reason is over use of the limited water resources in the middle reaches, shortage of surface water, and over pumping groundwater. But in Wuwei oasis, the development trend is different; the result is decrease in sandy land and increase in farmland.
  • GUO Yan-jun, ZHAI Pan-mao, LI Wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 755-760. https://doi.org/10.7522/j.issn.1000-0240.2004.0119
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    Based on NOAA satellite remote sensing data and conventional observations of snow cover in China, a comparison was conducted on snow cover in China is carried out. It is found that correlation between coefficient of monthly number of snow cover days from NOAA satellite data and furfacesurface ground station observations is was significant at 95% level in more than 64% areas of China. In North East (including east of Inner Mongolia) and northern Xinjiang, the correlation coefficient is highly significant. In North China and central middle of Inner Mongolia, the correlation coefficient is more significant in winter. The correlation coefficient in the Tibetan Plateau is lower as compared with other regions. According to NOAAoaa satellite data, the correlation of the regions where there is is no surface observations for ground to the number of snow cover days in the Tibet Plateau is not significant. The relationship between annual spatial mean numbers of snow cover days in the Tibet Plateau derived from satellite remote sensing and from station observations is insignificant. In general, variation of annual number of snow cover days in the Tibetan Plateau derived from NOAA satellite data and ground observation is different.
  • HAN Tian-ding, DING Yong-jian, YE Bai-sheng, XIE Chang-wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 761-766. https://doi.org/10.7522/j.issn.1000-0240.2004.0120
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    Based on monthly and annual precipitation data of the southern and northern slopes of the Tianger Range in Tianshan Mountains, the spatial-temporal variations of precipitation and the major changing trend are analyzed. Monthly precipitation is considered separately. The analyzed Precipitation series ranging from the 1950s to 2002 are collected from nine meteorological and hydrological stations, which scatter all over the southern and northern slopes of the Tianger Range in Tianshan Mountains. A statistical analysis shows that the increasing trend of precipitation is very obvious in the northern and southern slopes. The variable coefficient of precipitation is larger in the southern slope than in the northern slope, as such it is larger in winter and spring than in summer and autumn. There is a decreasing trend of the precipitation at Yingxiongqiao Hydrological Station in the Ürümqi River valley. The trend in March is more distinct, with a trend coefficient of -0.325. There is a significant inverse correlation between April to May and June to August at the Da Xigou Weather Station in the headwaters of the Ürümqi River, with correlation coefficients of -0.475 and -0.376, respectively.
  • CHEN Tuo, CHEN Fa-hu, AN Li-zhe, LIU Xiao-hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 767-771. https://doi.org/10.7522/j.issn.1000-0240.2004.0121
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    Since industrial revolution, a large amount of anthropogenic CO2 from fossil fuel combustion and deforestation has been emitted into atmosphere, and thus, the atmospheric CO2 concentration has increased rapidly, while the (δ13C) in atmospheric CO2 becomes lower and lower due to Suess effect. Therefore, prediction of (δ13C) is crucial for studying global change. In order to make an accurate prediction, it is necessary to understand its historical variation. The dynamics of (δ13C) in plants can sensitively reflect the variation. However, few studies are done of the stable carbon isotopes from high mountain regions, which are considered under ecological influence. In present paper, tree-ring and foliar (δ13C) values at different altitudes, as well as photosynthetic pigments, soluble sugar and nitrogen contents, were measured. The results showed that no strong dependency of (d13C) values on elevation was found both in tree rings and in leaves, but tree-ring (δ13C) values were more negative than foliar (δ13C) values. A significant negative relationship existed between foliar (δ13C) values and photosynthetic pigments; however, foliar (δ13C) values were not associated with leaf nitrogen and soluble sugar contents. During the past 50 years, tree-ring (δ13C) values becomes lower and lower, although the rates of decrease in (δ13C) values at different altitudes were different. The analysis showed thating (δ13C) values, and the decreasing trend of tree-ring (δ13C) values in the past 50 years was due to anthropological activities.
  • DONG An-xiang, LI DONG-liang, GUO Hui
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 772-778. https://doi.org/10.7522/j.issn.1000-0240.2004.0122
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    Impact of astronomical factor on ENSO events in the past 500 years and the possible relationship of El Nio and air temperature and ground temperature in the past 50 years are investigated along the Qinghai-Tibetan Railway. It is revealed that in El Nio years, annual mean temperature, mean annual maximum temperature, mean spring maximum temperature, mean minimum temperatures in the summer and autumn will decrease. But in La Nia years the aforesaid changes will be adverse. Mean annual minimum ground temperature and mean minimum ground surface temperature in the autumn and winter is similar to what above-mentioned. There is no confident connection of ENSO events and ground temperature at the depth below 5 cm. There are quisai-60-year and quisai-19-year periods in El Nio events. Its may be attributed to astronomical factor.
  • YU Xiu-jing, LI Dong-liang, HU Jin-biao
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 779-783. https://doi.org/10.7522/j.issn.1000-0240.2004.0123
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    By using the observational data from 50 stations, inter-decadal climatic variation was statistically analysis for recent 50 years in Jilin Province. It is found that the annual mean temperature gradually decreased in the 1950s and reached a low in the 1960s, and then gradually increased in the 1970s. Precipitation gradually decreased in the 1950s and reached a low in the 1960s and the 1970s, slightly increased in the 1980s, and then gradually decreased in the 1990s. Thus, it is believed that inter-decadal climatic variation over the 50 years in Jilin Province experienced a course of warm and cold-cold and dry-warm and humid-warm and dry. The maximum and minimum temperatures both have an increasing trend for the recent 50 years. However, the increasing rate of the minimum temperature is 2.3 times more than that of the maximum temperature. Finally, detections of climatic abruptness are made on annual mean temperature and annual precipitation by means of linear fitting for time intervals. It is found that precipitation had two abrupt turns in 1977 and 1987, and the annual mean temperature had only an abruptness in 1969.
  • LIU Guang-xiu, PAN You-fu, LU Wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 784-787. https://doi.org/10.7522/j.issn.1000-0240.2004.0124
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    The conductance,pH values, and the concentrations of major ions of glacier water sampled from the Qilian Mountains were measured. A comparison among glacier water, distilled water and tap water was carried out. The conductance of glacier water is 5.22?10-2 (s·m-1), which is only half of the tap water sample. The pH value of glacier water is also between the distilled water and tap water. The results showed that the Na+ concentration of glacier water is very low, and the TDS is only 101.50 mg·L-1. Experiments on plant seeds bourgeoning and plant tissue culture indicated that the glacier water is pure enough to be used in plant tissue culture. These show that the glacier is a very valuable and high quality water resource on the earth.
  • DU Yang, CHEN Xiao-fei, ZHANG Yu-long, MA Wei
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 788-794. https://doi.org/10.7522/j.issn.1000-0240.2004.0125
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    Measuring unfrozen water content in frozen soil by TDR is a new technique. It has many advantages. However, there is less experience in using the technique, and it is necessary to verify its reliability. The NMR is a mature technique in measurement of unfrozen water content in frozen soil. In this study, the freezing and thawing characteristic curves of umber soil with different initial water content were measured by TDR and NMR methods, and the reliability of the calibration curves of TDR method was verified. The result shows that the freezing and thawing characteristic curves measured by NMR and TDR is obviously different. At the same negative temperature, the unfrozen water content measured by TDR is higher than that by NMR, and the difference increases obviously with increase of initial water content. The results measured by NMR show that the initial water content has a little effect on the freezing and thawing characteristic curves. Whereas the results obtained by TDR show that the initial water content has obvious effect on the freezing and thawing characteristic curves, and the unfrozen water content increases apparently with increase of the initial water content. These results show that ice content and temperature have obvious effect on the dielectric property of frozen soil. So the intrinsic calibration curve of TDR for unfrozen soil should not be applied to the measurement of unfrozen water content in frozen soil directly.
  • ZHOU Guo-qing, MA Wei, BIE Xiao-yong, LIU Zhi-qiang, ZHAO Guang-si, SHANG Xiang-yu, WANG Jiang-zhou, DUAN Quan-jiang, XU Jiang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 795-799. https://doi.org/10.7522/j.issn.1000-0240.2004.0126
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    Aimed at the problem of the Qinghai-Tibet Railway embankment stabilization, which goes through the permafrost regions of high-temperature and rich ice, a new method that gathers and controls nature cold energy to keep the frozen soil embankment stabilizing is put forward in this paper. The method gathers the cold energy caused by the temperature difference between air and ground in winter and releases it in summer. Study on the embankment temperature field changing with time and space has been carried out under a typical engineer condition. The result shows that without additional measures, the temperature field in the embankment will not become into negative temperature until the 16th year after the railway construction finished. Thus, to keep the Qinghai-Tibet Railway embankment stabilizing, artificial work must be done to improve the embankment temperature field. This method can effectively keep the Qinghai-Tibet Railway embankment stabilizing.
  • LIU Jian-kun, BAO Wei-meng, HAN Xiao-gang, BAO Li-ming
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 800-805. https://doi.org/10.7522/j.issn.1000-0240.2004.0127
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    A new special structure of embankment-bridge transition section in permafrost regions is presented by modifying the structure of the transition section applicable to ecumenical regions, based on the observations of settlement and thermal state of a modified embankment-bridge transition section in Qingshuihe of the Qinghai-Tibet railway. The principle of permafrost protection is kept. The features of settlement and thermal state are analyzed, and the embankment-abutment transition method in permafrost regions, recommended in this paper, is evaluated.
  • SHEN Yong-ping, LIANG Hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 2004, 26(6): 806-809. https://doi.org/10.7522/j.issn.1000-0240.2004.0128
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Enormous resources of snow and ice are accumulated in the highlands and mountains of High Asia, and is the most concentrated glacier center in the middle and low latitudes on the Earth, covering an area of 104850 km2, including 23000 km2 in India, 16933 km2 in Pakistan, 5322 km2 in Nepal, and 49873 km2 in China. These glaciers receive more abundant precipitation than other regions. Annual precipitation at the equilibrium line varies from 500 to 3000 mm, and a high precipitation zone is in the glacier cover regions, formed a second maximum precipitation with altitude. High mountain massifs are advantageous for catching water vapor and the consequent development of large glaciers. Author sends a possible formation mechanism of high precipitation in glacier zone. Cold ice surface would drive an airflow sinking as the air mass passing, and result in high precipitation in glacier zone of the mountains. Other hand, there are more moisture over glacier than surrounding bar rock slopes, and a strong evaporation from glacier surface make high moisture center in the glacier cover zone. The cold surface and more moisture from glacier zone could be cause of high precipitation zone formation in glacier cover zone of High Asia.