25 May 1992, Volume 14 Issue 2
    

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  • JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 97-100. https://doi.org/10.7522/j.issn.1000-0240.1992.0015
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  • Wang Jiacheng, Cheng Guodong, Zhang Hongding, Liu Jimin
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 101-106,191. https://doi.org/10.7522/j.issn.1000-0240.1992.0016
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    To study the conditions of ice formation during soil freezing and thawing, the controlled freezing and thawing test on the saturated sand was conducted in the laboratory. The results have shown that the temperatue at the end of the soil column changing periodically, which induces the freezing-thawing surface in the soil column moving up and down, is the necessary condition for ice formation. By the mechanism of vacuum and permeableness water is adsorbed to the place nearby the freezing-thawing surface and ice formed. Having water supply from the outside of the soil column is the ample condition for ice formation. It results the thickness of ice layer continuously increasing in freezing and thawing cycles. The location and the thickness of ice layer depend on the location of freezing-thawing surface and the times of freezing and thawing cycles. If the freezing-thawing surface keeps constant after each freezing and thawing cycle, then the thicker ice layer will be formed. In each freezing and thawing cycle, if the thaw depth is greater than the frost depth, then only one thin ice layer can be formed and contrarily, if the thaw depth is less than the frost depth, then multiple thin ice layers will be formed after many times of freezing and thawing cycles.
  • Ding Yongqin, Chen Xiaobai
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 107-114. https://doi.org/10.7522/j.issn.1000-0240.1992.0017
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    The salt-frost susceptibility tests of Lanzhou loess mixed with different percentages of Na2SO4 and NaCl by weight were conducted. The mechanism of salt-frost heave was explained by the isothermal phase diagrams. Some new results, could be concluded as follows:(1) The total heave of saline soil increases with the enlargement of Na2SO4 · 10H2O crystallized during cooling from 25℃ down to -15℃. Additional content of NaCl in the soil could restrain the crystallization of Na2SO4, which will reduce heave amount. However, while the ratio of NaCl to Na2SO4 by weight exceeds a critical value, the crystallized amount of Na2SO4 · 10H2O and NaCl · 2H2O will grow with the increase of NaCl. Consequently, the salt heave will be getting stronger.(2) An additional amount of NaCl mixed in the soil will restrain Na2SO4 · 10H2O crystallized during cooling from 25℃ down to 15℃. While the ratio of NaCl to Na2SO4 exceeds a critical one, both crystallized Na2SO4· 10H2O and heave will disappear.(3) As the ratio of NaCl to Na2SO4 exceeds the critical value, there are two salt-frost heave peaks in the temperature zones of 15℃ to 13℃ and -5℃ to - 12℃ respectively.
  • Wang Guangyu, Zeng Qunzhu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 115-121. https://doi.org/10.7522/j.issn.1000-0240.1992.0018
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    The variation features and their correlations of snow cover area in three regions of North America, Eurasian continents and Tibet plateau in Northern Hemisphere were analyzed using NOAA/National Enviromental Satellite snow cover data of Northern Hemisphere from 1967 to 1983. The results show that there were different developing rules in the three regions. The annual variation of Eurasian snow cover was the most obvious in the three regions, the interannual change of Tibet plateau was the most obvious in the three regions. There were about 3 months, 6 months and 10 months periodic peaks in the changes of snow cover areas of North America and Eurasian, and 1.5 years, 3 years periodic peaks in Tibet plateau. There was a notable condensation in the changes of snow cover area of three regions on 6 years periodic oscillation, nevertheless Eurasian snowcovar falls behind North America about 2 months, falls backward Tibet plateau about 10.58 months.
  • Yang Daqing, Zhang Yinsheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 122-128. https://doi.org/10.7522/j.issn.1000-0240.1992.0019
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    According to the evaporation pan measurements, the daytime snow surface sublimation rate and night-time condensition rate are 0.012 mm/h and 0.005-0.010 mm/h, respectively, in the mid-alpine area of the river basin during midlle winter mounths. The daily sublimation from the snow pack reachs to 0.03 mm in January and 0.16 mm in February in the mid-alpine area. Since the climate in the high alpine area is drier in the winter, the average daily sublimation increases to 0.21 mm in February and 0.54 mm in March, which is close to the daily sublimation from snow surface of the Glacier No.1 in the summer of July and August. Snow surface sublimation in the high alpine area mainly depends on the thermal condition, that is, it changes proportionally along with the daily maximum air temperature. The monthly sublimation ranges from 4.6-5.5 mm in February and 7.9-9.5 mm in March, respectively, in the river source area, accounting for 55-100 percent of the monthly precipitation.
  • Zhang Zhizhong, Yang Daqing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 129-133. https://doi.org/10.7522/j.issn.1000-0240.1992.0020
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    The seasonal snow cover in Urumqi River Basin varies temperally, influenced by air temperature, precipitation, moisture source, slope direction, elevation and ground surface condition. Snow cover is divided, by its duration, into four classes as the new snow, short term snow cover, long term snow cover and permenent snow cover. The snow cover is characterized by shallow snowpack, less snow density and high evaporation rate in the winter.
  • Liang Linheng, Zhou Youwu
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 134-140. https://doi.org/10.7522/j.issn.1000-0240.1992.0021
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    Through the investigation of the thickness and density of snow cover in winter at different geomorphologic positions and vegetation zones in Amue forest fire area of Da Hinggan Ling, northeastern China, the snow thickness on swamp-land is thicker than on slope, and that on burned site is 3 cm thicker than on unburned site in the same forest zone. The maximum accumulated snow cover in this region is about 60 cm. The snow density on burned site is bigger than on unburned site, it is the biggest on uncovered site. According to calculation, the increased amount of mean annual ground surface temperature by snow cover with about 30 cm thickness is 2.8-5.0℃.
  • Kang Xingcheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 141-152. https://doi.org/10.7522/j.issn.1000-0240.1992.0022
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    Based on measuring data from Chongce ice cap area of West Kunlun Mountains, the daily variation of wind direction, wind speed and air temperature in the glacial and non-glacierized area as well as their variation of temperature on horizontal and vertical direction were revealed. The results show that the wind from the glacier region is prevailing and there are wind shear, convergence and divergence zones between the glacial and the non-glacierized area. The atmospheric-superadiabatic stable state occurred in the glacial region for all day, but in the non-glacierized area the atmospheric superadiabatic unstable state occurred in daytime, and a phenomen on of inverse temperature in nighttime. Therefore, the variation of temperature on horizontal direction occurred mainly in the front of the ice/snow region. So we suggest a specific phenome on "the glacier front" in the glacial area.
  • Deng Xiaofeng, Zhang Wenjing
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 153-160. https://doi.org/10.7522/j.issn.1000-0240.1992.0023
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    Based on the field investigation and sample analyses, three glaciations on the eastern side of the Geladandong Peak since middle Pleistocene have been recognized. Their scales, types are mainly discussed as follows: (1) the glacial characteristics of the last Glacial maximum dated back to 18010±386 a B.P., was of monsoonal continent type. The glacier terminal reached 5120 m a.s.l., The snow line elevation was about 5533 m a.s.l.; (2) the glacier of the penultimate glaciation was of transition features between the monsoonal and the maritime glaciers, the age is suggested to a cold period in middle Pleistocene, the altitude of terminals 4950 m a.s.l., the altitude of snowline 5238 m a.s.l., and the lower trough was formed in this period; (3) the glacier of the pre-penultimate glaciation was a maritime ice cap, the glacial thickness reached 200-300 m, the U-shaped valley was sculptured and the upper till sheet deposited in this stage. It is the earliest and greatest glaciation in this area.
  • Zhu Cheng
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 161-167. https://doi.org/10.7522/j.issn.1000-0240.1992.0024
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    This paper deals with the comprehensive division of the global periglacial geomorphology for showing the significance on the entire features of the global periglacial processes and their environment. Author absorbed predecessors essence on periglacio-climatic classified principle, and divided the global periglacial landfrom into 4 types and 11 subtypes based on domestic colleagues 5 years fixed position observational data, and foreign colleagues recent studying results.
  • Xie Yonggang
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 168-173. https://doi.org/10.7522/j.issn.1000-0240.1992.0025
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    The freeze-up and break-up of ice cover on the reservoir is a popular natural phenomenon in cold region. Movement of the ice cover can damage the slope protection of the dam, causing losses in economics. Based on calculating and analyzing to the data of a decade observation on the ice cover formation and break-up on the shengli Reservoir, Heilongjiang Province, auther points out the characteristics of the ice cover movement and the distribution of peach-like pattern pressure field, and states the process of the ice thickening and vanishing, as well as the regularity of the ice cover activity. It can provide the scientific basis for the Shengli Reservoir engineering design and its ice-hazard protection.
  • Lu Ruren
    JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 174-177. https://doi.org/10.7522/j.issn.1000-0240.1992.0026
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    A catastrophic debris flow of meitwater-rain type occurred in the Nanguan gully on the left bank of the middle reaches in ihe Yunzi Valley of the east slope in Mt. Gongga at 15-18 h, on 26 July, 1989. It destroyed a large highway bridge, blocked up the Dadu River and forced main flow line of the Dadu River towards the left bank. The Luding-Shimian Highway was washed out a length of 820 m, and the road had been closed for 9 months. The economy loss of 2.45 millions Yuan was estimated.The Nanguan gully, located at 101 ° 54 ’ 37.1 " -101 ° 59 ’ 11.3 "E, 29° 41 ’ 23.9 " -29 ° 44 ’ 39.5 " N, has an area of 19.8 km2 large with a glacier area of 0.84 km2. The elevation range is 3988 m, average longitudinal gradient of main gully bed is 215.7‰.A length of flow way of the debris flow is above 30 km, it appears in gustiness lasting 3 hours. The fluid appears in viscousness. The maximum weight of the unit volume is from 2.0 to 2.4 t/m3. The velosity changes from 8.2 to 11.7 m/s. The peak flood changes from 2336.0 to 6775.2 m3/s. The total runoff into the Dadu River is about 1 716.4 × 104 m3, with the mud, sand and stone of 627.0 × 104 m3. The height creeping up of debris flow on the bend way is 15.5 to 16.5 m. A total of remaining sediments in the gully bed is 310.4 × 104 m3. The debris flow body filled all the gully bed on its flow way, made sedimentation of overflowing, decelerating and back flowing.
  • JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 178-183,192. https://doi.org/10.7522/j.issn.1000-0240.1992.0027
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  • JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1992, 14(2): 184-186. https://doi.org/10.7522/j.issn.1000-0240.1992.0028
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