25 February 1998, Volume 20 Issue 1
    

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  • ZHANG Yin-Sheng, YAO Tan-Dong, PU Jian-Cheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 3-8. https://doi.org/10.7522/j.issn.1000-0240.1998.0002
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    This paper takes the Dongkemadi Glacier in the Tanggula Mts., the Glacier No. 1 in the headwarters of the Urumqi River in the Tianshan Mts. and the July First Glacier in the Qilian Mts. as studying objects. The energy mechanisms for glacier fluctuation are discussed. As an indictor of climatic change, the ELA has linear correlation with mass blance. A model is established to study and forecast the ELA. From this model, it can be obtained the ELA responding to climatic factors under different future climatic scenarios. Meaewhile, the future effects of climate change on mass balance were also forecasted. Among the three glaciers, the Glacier No. 1 is more sensitive to climate fluctuation, and the July first Glacier, with its especial features of energy exchange, is quite sluggish to climate fluctuation so that the glacier is almost stationary under the background of most glaciers all over the word in retreat.
  • LIU Shi-Yin, DING Yong-Jian, WANG Ning-Lian, XIE Zi-Chu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 9-13. https://doi.org/10.7522/j.issn.1000-0240.1998.0003
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    In this paper the degree-day mass balance model is applied to the sensitivity test of mass balance /ELA to climate change of the Glacier No.1 at the Urumqi river head, Tianshan Mts. Results demonstrate that mass balance of a continental type glacier with warm season accumulation as the Glacier No.1 is less sensitive than that of a maritime type glacier. On the glacier air temperature rise of 1℃ or precipitation increase by 20% can cause the ELA shifting 81 m up or 31 m down. Air temperature and precipitation play different roles in mass balance, i.e. elevation-dependent mass balance follows the temperature variation by means of rotation against the elevation axis and it shifts parallel to precipitation change. Assuming a future temperature rise of 2 ℃ the minus mass balance trend of the glacier can not be reversed even if precipitation increases by 30%.
  • WANG Ning-Lian, YAO Tan-Dong, L. G. THOMPSON
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 14-20. https://doi.org/10.7522/j.issn.1000-0240.1998.0004
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    Nitrate(NO3-) in precipitation comes from various sources, which cause many difficulties in understanding its environmental implication. Nevertheless, study of the major sources of NO3- in an ice core can not only recognize its environmental implication, but also interpret its secular variation. By analyses, it is found that solar activity, oxidation of nitrous oxide in the stratosphere and continental air mass (mainly including crustal dust and content of soluble materials in vapour in air mass) are the major sources of NO3- in the Guliya ice core. Spectral analysis of the variation of NO3- concentration in the recent 1 500 years shows strong periodicities of 23.3 a, 88.1 a, 30 a, 5.5 a and 10.4 a. Nearly all the periodicities are close to or consistent with solar activity periodicities of 22 a, 80~100 a, 5~6 a and 11 a, except the periodicity at 30 a, which is close to the periodicity of water level variations of lakes in the central Asia, about 31~34 a. Solar activity is a major factor in controlling the variation of NO3- concentration in the ice core. The secular variation of solar activity and NO3- concentration show a remarkable positive correlationship. The Maunder Minimum, Sporer Minimum, Medieval Maximum and Medieval Minimum of solar activity can be seen obviously in the curve of the variation of NO3- concentration in the Guliya ice core in the recent 1 500 years. By cross spectral analysis, it is found that there is a phase lag, about 1.5 a, between the variation of NO3- concentration in the ice core and solar activity at the periodicity of 11 a, and the variation of sunspot numbers are in advance.
  • LIU Guang-Xiu, WANG Rui, LI Shi-Jie, LI Bing-Yuan, ZHU Zhao-Yu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 21-24. https://doi.org/10.7522/j.issn.1000-0240.1998.0005
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    Pollen record from a drilling core 56.32 m in depth in the Tianshuihai Lake, West Kunlun Mountains, indicates that alpine desert vegetation is dominant since 240 ka BP in this region, but there are several fluctuations of Artemisia which is main component of steppe, reflecting that there exist several warmer and weter intervals under the cold and dry climate background. According to the changes of pollen kinds and the ratio of Artemisia and Chenopodiaceae (A/C), the pollen record can be divided into 10 zones, showing 10 climatic fluctuations and an ecological environment fragitity in this area.
  • JIN Hui-Jun, LIU Zong-Xiang, Toshio SONE
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 25-29. https://doi.org/10.7522/j.issn.1000-0240.1998.0006
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    Permafrost temperature was measured in Borehole No. 5 in the Ice Pass at the source of the Urumqi River, the highest (3 900 m a.s.l.) borehole in the Tianshan Mountains, since September 1991. The results of the temperature measurements indicate significant diurnal, seasonal and annual variations. Strong influences from flowing water and percolation have been detected in a coarse gravel layer at a depth of about 2 m during autumn each year. A zero curtain (0℃) extends from late August until October. The mean annual ground temperature and the thickness of permafrost are estimated as -5.0℃ and 240 m, respectively. The annual range of ground (rock) temperature at the depth of 18 m is less than 0.6℃; the depth of annual temperature change is estimated down to 25~30 m. The ground temperature indicates a rising trend at the active layer and a cooling one at 10 and 18 m in the permafrost during the 5 observation years. This can be attributed to the high temperature during the summer of 1995, the low temperature during the winter of 1994~1995, and to the heavy rainfall during the autumn of 1994.
  • LIU Shi-Yin, CHENG Guo-Dong, LIU Jing-Shi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 30-35. https://doi.org/10.7522/j.issn.1000-0240.1998.0007
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    The relationship between jokulhlaup from the Lake Mertzbakher in the Tianshan Mts. and climatic parameters, esp. air temperatures, is analysed based on the long-term records of the outburst floods since 1956. It can be concluded that monthly air temperature variation, which gives rise to the change of ablation duration and rate of the South and North Inilchek Glaciers, play an important role in the fluctuations of the water level and the drainage of the Lake Mertzbakher. A general increasing trend has been prevailed in the temporal variation of peak and total discharges of the jokulhlaup floods of the lake. Such an increasing trend is well coincided with the regional warming in the Tianshan Mountains during the last few decades.
  • WU Zi-Wang, ZHU Lin-Nan, GUO Xin-Ming, WANG Xiao-Yang, FANG Jian-Hong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 36-41. https://doi.org/10.7522/j.issn.1000-0240.1998.0008
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    The survey and drilling investigation in the permafrost regions along the Qinghai-Kangding Highway, which has been operated for 35 years, indicate that the line where the height of the embankment is lower than 0.8 m suffers from frost boiling and thermokast to different extent every year, and that the line where the height of embankment was over 0.8 m maintains a steady state. Based on an overall analysis on the change in permafrost table under the embankment, after considering the fact that the permafrost in the area is degrading and the requirement of the deformation of the road surface of high quality, it is suggested that the height of embankment is 1.6 m for the gravel road, and 2.0 m for cement concrete road in the plateau permafrost regions.
  • SHEN Zhong-Yan, ZHANG Jia-Yi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 42-45. https://doi.org/10.7522/j.issn.1000-0240.1998.0009
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    The dependence of dynamic strength of frozen silt on loading effect under constant strain rate are discussed in this paper. Losding effect consists of rate effect and fatigue effect. Dynamic strength and unloaded dynamic elastic modulus increase with increasing strain rate. However dynamic strength of frozen silt decreases due to fatigue effect, except for low strain rate. In high strain rate the dynamic strength is larger than the static strength of frozen soil, and in low strain rate the former is less than the later. There is a critical strain rate in between. Limit of long-term dynamic strength can be derived from the relationship between the dynamic strength and the vibratory number to failure.
  • LIU Hong-Xu, SUN Yan-Fu, CHEN Ya-Ming, XU Xue-Yan, YIN Yan-Hua
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 46-50. https://doi.org/10.7522/j.issn.1000-0240.1998.0010
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    In winter, a stiff layer of seasonally frozen ground is formed on the upper part of the ground surface. The dynamic properties of foudation soil then change to some extent, so do the brilliant periods of foundations. From the investigation on the seismic damages due to the two earthquakes in the summer and winter of 1986 in Dedu Prefecture, Heilongjiang, it is found that for the winter earthquake, the buildings with more rigidity are damaged more seriously, and for the summer earthquake the characteristics of seismic damages are just the contrary, i.e., the more flexible structures are damaged seriously. This is also supported by analyzing calculation and observation in situ.
  • LEI Zhi-Dong, SHANG Song-Hao, YANG Shi-Xiu, WANG Yi
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 51-54. https://doi.org/10.7522/j.issn.1000-0240.1998.0011
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    Using the model of simultaneo us moisture and heat transfer during soil freezing and thawing, a numerical sumulation is carried out to the whole course of freezing and thawing in Hetao irrigation areas in Inner Mongolia Autonomous Region. Moisture and heat transfer is analyzed based on the simulation. The result shows that freezing speed decreases linearly with soil depth. The increment of water content during soil freezing at a certain depth correlates with freezing speed in hyperbolic style. A concept of typical water content during soil freezing and thawing is proposed to describe the change of water content.
  • Ma Qin-Yong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 55-59. https://doi.org/10.7522/j.issn.1000-0240.1998.0012
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    The wave velocity and blastability are theoretically analysed. The longitudinal wave velocity, transversal wave velocity and blastability are measured in samples of frozen clay and sand under the temperature of -7℃, -12℃ and -17℃ respectively. The results show that the longitudinal wave velocity is closely correlated to strain energy factor and exhibits the blastability of frozen soil.
  • ZONG Qi, MA Qin-Yong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 60-63. https://doi.org/10.7522/j.issn.1000-0240.1998.0013
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    Model experiments on paramenters of frozen soil smooth blasting are conducted. The effect of model experiments shows that smooth blasting technology may be used in frozen soil blasting and that for hole diameter of 35~50 mm, more reasonable smooth blasting paramenters are coefficient of hole-spasing m=0.8~1.2 and hole interval E=500~700 mm,and more reasonable charge structure is air decoupling and air cushion charge.
  • KEChang-Qing, LI Pei-Ji
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 64-67. https://doi.org/10.7522/j.issn.1000-0240.1998.0014
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    The snow depth data of SMMR (1978~1987) and daily snow depth data at 55 primary meteorological stations covering the period of 1963~1992 were used to analyse the spatial and temporal characteristics of snow cover over the Tibetan Plateau by using EOF method. The results show that the spatial distribution of snow cover over the Plateau is very inhomogeneous. It is found that heavy snow cover appears in the periphery, especially in the western and eastern parts of the plateau, while light snow cover appears in the vast interior of the plateau. The heavy snow cover region in the east of the plateau is also the region where the most significant interannual variation of snow cover occurs, and dominates the interannual variation of snow cover in the whole plateau. There is an opposite phase relation between the western parts and the eastern parts of the plateau in the interannual fluctuation of snow cover. There is an increasing trend of interannual fluctuation amplitude of snow cover over the plateau from the 1960s to the 1980s.
  • WANG Shi-Jie
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 68-73. https://doi.org/10.7522/j.issn.1000-0240.1998.0015
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    Snowpack volume in the Urumqi District and the mid-section of the Tianshan Mountains etc. is estimated from the NOAA/AVHRR data. Rectification of orientation, regional automatic windowing, zonal altitute superposition and measurement of snow depth and volume are suggested in this paper, along with their verification, supplementation and modification. The followings are mainly discussed: 1) Every step of comprehensive analysis on snowpack volume;2) Conversion formulas among snow area, depth and volume; 3) Error treatment; 4) Interannual difference in snowpack volume in the same season. For error treatment, some correction coefficients are presented.
  • JIANG Feng-Qing, WEI Wen-Shou, LIU Ming-Zhe, LI Wei-Hong, WANG Xin-Jun
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 74-78. https://doi.org/10.7522/j.issn.1000-0240.1998.0016
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    Kunnes River is one of the tributaries of the Yili River in Xinjiang. Tianshan Station for Snow and Avalanche Research, Chinese Academy of Sciences, stands at its upper reaches. Snow chemical surveys were carried out in spring of 1996 and winter of 1996/1997. About 100 snow and river water samples were collected along the river. Then, the samples were analyzed by methods of common chemical analysis and IDMS in our institute. The results show that concentration of Ca2+ varies in a range from 2 to 12 mg/L, and that of Mg2+ is between 0.9 and 2.5 mg/L. The concentration of K+and Na+ changes from 4.4 to 8.76 mg/L. There are obvious influences of anthropogenic factors on the snow chemistry. A relative high concentration of sulphate is found within the snow. The sulphate is mainly from the dried lakes and desert in central Asia. In regard to heavy metals, the concentration of Zn varies in a range from 0.01 to 0.05 mg/L, and Pb is lower than 0.1 mg/L. The concentrationsof Cu and Cd in the snow samples are very low, lower than 0.005 mg/L.
  • LIU Yong, DENG Xiao-Feng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 79-84. https://doi.org/10.7522/j.issn.1000-0240.1998.0017
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    The Xixiabangma-Qomolangma area has uplifted rapidly since Neocene, under the geological background of collision of the Eurasia Plate with the Indean Plate. With the dramatical tectonic uplift in Quaternary, advance/retreat of glaciers, development of rivers and change of lakes all underwent dramatic shifts, and induced the entire change of geomorphological pattern. In the Penultimate Glaciation, i. e. the maximum Nieniexiongla Glaciation, large scale of glaciers or small ice sheet developed in this area, covering all the area. The glaciers in the Last Glaciation were mainly large and long valley glaciers and small ice sheet. In the Last Interglaciation, the erosion ability of rivers enhanced, the rivers in the south side of the Himalayas made strong backward erosion, cut into the core of the mountains, destroyed their entirety, captured rivers in the north side, and changed fundamentally geomorphological pattern in this area. In the Climatic Optimum of middle Holocene, the Peiku Lake got the highest water level and the widest area in its geological history, when the water level was just 100 m higher than that at present. Afterward, water supply became less and less, water area shrinked rapidly, and water level reduced with the backward erosion and capture of the Pengqu River.
  • DENG Xiao-Feng, LIU Yong
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 85-87. https://doi.org/10.7522/j.issn.1000-0240.1998.0018
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    Based on in situ investigation on elevation variation of palaeo-lake bank of the Peikucuo Lake, river valley terraces and glacio-fluvial terraces of the Menqu River in the north slope of Mt. Xixiabangma, and combined with interpretation of topographic map, satellite and air photoes, this paper refers and confirms the uplifting scale in different period, variation of palaeo-geographic environment, change of glaciation and inter-glaciation, evolution of animals and plants since the Quaternary. During the Quaternary, the glacio-fluvial deposits in the north slope of Mt. Xixiabangma has blocked the Menqu River valley and formed Peikucuo barrier lake. Evolution of the lake corresponded to the change processes of glacier types from valley glacier, piedmont glacier to valley glacier.
  • WANG Guo-Shang, JIN Hui-Jun, LIN Qing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1998, 20(1): 88-92. https://doi.org/10.7522/j.issn.1000-0240.1998.0019
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    In recent two decades or so, time-domain reflectometer (TDR) have greatly developed in soil parameter measurement. Especially in soil water content determination, it has great practical application and developing potentiality. This paper briefly introduces recent progresses of TDR. In the mean time, its determining items and precision are also presented. Now, it is expected to use TDR in China.