25 August 1991, Volume 13 Issue 3

    

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  Greenhouse Effect and Climate Change

  Li Peiji

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 189-200. https://doi.org/10.7522/j.issn.1000-0240.1991.0028

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  It is now generally recognized that anomalies in radiative forcing Induced by trace gases of anthropogenic origin can become the dominant factor governing climate change on decadal to longer time scales. Some time in the next century the earth’s climate is expected to undergo a major warming as a result of greenhouse effect.Non-CO₂ greenhouse gases in the atmosphere are now adding the greenhouse effect by an amount comparable to the effect of CO₂. The problem concerning the greenhouse effects has broadened in scope from the CO₂-climate problem to the trace gas-climate problem.The new models behave more like the real world than earlier one’s in two ways. They simulate the effects of gradual, rather than instantaneous, increases of greenhouse gases and transient response to the climate system. They transfer heat from the atmosphere into the deep ocean and carry it in surface water toward the poles, all in currents that can vary in response to climate change. But they are still not running a realistic ocean. The new modles do not include in a physical way the horizonal transports of heat, momentum, and salinity and could not therefore correctly simulate the regional distribution of climate.Recent simulations suggest that global greenhouse warming will soon rise above the level of natural climate variability. The greenhouse theory of climate change has reached the crucial stage of verification. While the evidences for climate change are meaningful, no one is claiming a certain identification of the greenhouse signal. Any intensification of the greenhouse is not yet detectable above the background of natural climatic noise. To say that the greenhouse is here now is just a logical, well-reasoned conclusion.
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  Research on Glaciers and Climate Fluctuation in Turgen-Asu Valley, Terskey Ata-Too Range

  O. Solomina, N. Melnikova

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 201-212. https://doi.org/10.7522/j.issn.1000-0240.1991.0029

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  Reconstruction of Turgen-Aksu valley glacial history and precipitation regime is made using methods of moraine lichenometry and dendroindication. Cores of Picea Shrenkiniana were sampled at the upper forests line at the height about 2 900 m. After the correlation analysis of ring-width indices and meteoparametrs obtained on meteostation Krasny Oktiabr we decided the precipitation to be the limiting factor of Picea growth. Equations of line regression for year and cold period precipitation and row of ring-width indices (mean for 5 trees) were calculated using 5-year smoothing of data. Then the year amounts of precipitation for the period 1600-1983 were calculated according to the equation. Coefficient of correlation between row of ring-width indices and observational data on meteostation Krasny Oktiabr 0.83.Another part of this paper is devoted to the moraine age indication. The following forms of licheons were used for evaluation of the moraine age of three glaciers in Turgen-Aksu value Caloplaca elegans, Placonlecanora muralis, Aspicilia sp., Rhizocarpon geographicum. All the moranies were formed in the XIX-XX centuries, the previous didn’t survive.According to the reconstruction, the most moist period of recent 380 years was from the end of XVII to the end of XVIII century. The maximums precipitation occurred in the decades of 1670-th, 1720-th, 1750-th, 1770-1990-th, and 1830-th. One of the strongest glacier’s advance which occurred in the latest of these periods had left its traces in the moraine. Periods of high precipitation in the XX century also coincide with periods of glaciers advance. That’s why we make a proposal that advances of glaciers in this region were occurring during all of the main maximums of reconstructed precipitations, even in the case we don’t find moraine as their trace.
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  A Simple Method on Estimating Glacial Mass Balance

  Ding Yongjian, Xie Zichu

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 213-218. https://doi.org/10.7522/j.issn.1000-0240.1991.0030

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  It has been mathematically proved that mean gross accumulation or ablation in a whole glacier is equal to that at equilibrium line as the glacier is in zero balance. On the basis of this result, the relationship is discussed between the gross accumulation in a whole glacier and that at the equilibrium line undr general circumstances. When a glacial mass balance (B) is negative, its mean gross ablation (A) is greater than that (A_H) at the equilibrium line. When B is positive, A is smaller than A_HH. According to the mentioned results, a new conception of "relative mass balance" that can be estimated by difference between A and A_H was advanced. Glacial mass balance and relative mass balance are of the same significance in a judgement of profit and loss of mass on a glacier. Lastly, a method to calculate relative mass balance was put forward through examples. By this work information on glacial mass balance that must be obtained from long time measurement could be got only from climatic element which is just mean summer air temperature (June to August) obtained from meteorological stations.
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  A Preliminary Study on the Drainage System in the Ablation Area of the Glacier No.1 at the Source of Urumqi River

  Kang Ersi

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 219-228. https://doi.org/10.7522/j.issn.1000-0240.1991.0031

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  The water channels are developed on the glacial surface and at the glacial sides, some meltwater runs into or under the glacier throuth the crevasses, the moulins and the glacial sides, through the englacial-subglacial water channels and finally out off the glacier, forming the glacial drainage system. The salt tracer experiment was conducted at the Glacier No.1, 7 injection points of which were distributed on the ablation area and the accumulation areaimmediatly above the equilibrum line, the one dimensional dispersion equation is employed to calculate the curves of the salt condensation versus time and the dispersion coefficient. The observation and calculation show that the confluence of meltwater is rather rapid in the ablation area. It only takes 1-2 hours for the meltwater to run to the glacial gauge station during the period of complete development of the glacial drainage system, but in the accumulation area, the retardation of the snow and firn layers to meltwater runoff should be considered. The storage function of the glacier to meltwater runoff is weak, it makes the meltwater runoff nearly all drained out off the glacier, after a short time stay in the drainage system. The anabranches, flow eddies and the retardation of sediments to runoff exist in the drainage system, it makes the observed curves of the salt condensation versus time lower and extending time longer than that of calculated curves, but the prolonged time is generally only in several to 15 minutes, even in the accumulation area hear the equilibrium line is only in about 60 minutes. The dispersion equation can basically be applied to simulate the curves of salt condensation versus time of the salt tracer experiment, this clarifies that the englacial-subglacial water channels are rather unitary, instead of complex divergence. The dispersion coefficient of the drainage system in the ablation area is calculated generally to be 0.5-1.5 m²/ s.
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  Analysis of Recent Change on Runoff of Melt Ice and Snow in Head of Urumqi River

  Zhu Shousen

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 229-236. https://doi.org/10.7522/j.issn.1000-0240.1991.0032

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  The observation in the past 30 years shows that the No.l Glacier at the head of the Urumqi River has been retreating since the 1960’s. The glacier runoff was close to average in the 1960’s, lower than average in the 1970’s and higher than average in the 1980’s. The changes of the glacier and runoff are not identical. That is because they both have different time scale to response to climatic changes. According to analyses the present paper disccused the features of the runoff change under the particular climatic conditions. It is revealed that it is advantageaus to the production of runoff under the conditon of dry ang warm climate or higher air temperature and abundant precipitation, and it will be advantageaus to the development of glaciers under lower temperature and adundant precipitation or the rise in the winter accumulation. Calculated results indicate that mean air temperature from May to September in the hydrological station of the No. 1 Glacier increases 11, the runoff volume will be raised by 9.86×10⁵m³, if mean air temperature from Jane to August increases 1℃, the volume will be raised by 1.142×10⁶m³; if annual mean air temperature in the No.l Glacier increases 1 ℃, the volume will be raised by 1.257× 10⁶m³ and the volume will reise 1.577 ×10⁶m³ if the summer temperature increases 1℃.
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  Elastoplastic Calculation of Bottom Heave in Artificially Frozen Shaft

  Ma Wei, Wu Ziwang

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 237-246. https://doi.org/10.7522/j.issn.1000-0240.1991.0033

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  When a frozen shaft is sunk after negative freezing period, vertical and horizontal earth pressures are primary factors causing bottom heave. Based on this, a mechanical model is proposed for calculating the deformation of frozen shaft. Using elastoplastic methods, we obtained semianalytic formulas about the bottom heave u(h₁) the maximum radius displacement of frozen soil wall u_m and lead displacement u_b:Results of the simulating calculation are in good agreement with results observed in the No.3 Tongfeng shaft, Panji, which shows the model feasible. The calculated results can also explain why freezing tubes are frequently destroyed in the clayey soil layer of calyey-sandy alteruating layers.The semianalytic formulas can be applied to predict the deformation of a frozen shaft at any depth and provide the theoretical reference results for engineering designer.
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  Frost Susceptibility of Powdered Calcium Carbonate

  Chen Xiaobai, Corte A.E., Wang Yaqing, Shen Yu

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 247-253. https://doi.org/10.7522/j.issn.1000-0240.1991.0034

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  Experimental results show that an ice segregation and consquently a strong frost heave could occur in powered calcium carbonate while rich in moisture. Some regresion formulas could be expressed by: T_f=-5199.62W^-3.274, R=-15.40+5.71 lnW In Win closed system and η=4.495V_f^-1.109 in open system, in where, T_f, W, R, η and T_f are its freezing point, water content, frost heave rate, heave ratio and frost penetration rate respectively. However, its frost susceptibility might be controlled by moisture and a special anti-heave agent mixed in.
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  Application of D.C.Electric Sounding for Permafrost Exploration along Xinjiang-Xizang Highway

  He Yixian

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 255-260. https://doi.org/10.7522/j.issn.1000-0240.1991.0036

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  D.C.electric sounding, as one of main means for permafrost exploration along Xinjiang-Xizang Highway in 1987, had been used in delineating the pennafrost borders along this highway. The north boundary of continous permafrost is located at dry valley about 10 kilometers south of Dohongliutan, where the elevation is 4 450 m. The south border of continous permafrost is near a marsh land, 4 630 m a.s.l., about 30 kilometers west of Duoma, while Duoma, with the elevation of 4 430 m, is the south lower limit of sporadic permafrost.At the bank of Tianshuihai lake, large blocks of groundice were found, the thickness of groundice measured by D.C. electric sounding is 20 meters, while the thickness of permafrost is 84 meters. Because of climatic cycle changing and lake alteration, the thawing layer has formed in vertical distribution of permafrost at Tianshuihai basin. The thawing layer is 10 meters thick. The thickness of permafrost overlaying on these thawing layers, found by D.C. electric sounding, is 6 meters.
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  BZXJ, A Super Light-weight Core Drill

  Zhu Guocai, Han Jiankang, Liang Suyun, Gao Xinsheng, Zhang Wanchang, Zhang Yongliang, Wang Xiaojun

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 261-266. https://doi.org/10.7522/j.issn.1000-0240.1991.0037

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  BZXJ is a type of super light-weight core drill capable of drilling to 100-200 m depth in cold ice. The weight of this complete drill system is 130 kg, in which the dynamic drill head only weights 11 kg. The three dimensional volume of the drill system is no more than 1.2×0.4×0.4 m. It consumes power of 200 W with mean cutting speed of 8-10 mm·s^-1 when cutting the ice. A core till the bedrock was successfully completed on Nov. 1990 at Giacier No.l, Tianshan, China. In the upper part of 40 m of the glacier, the drilling speed can reach to 5-6 m ·hr^-1, the average drilling speed in the range of 90 m depth is about 5-6 m ·hr^-1. The practice demonstrated that it posses advantages of light weight, less volume, easy to transport, simple for handling, fast operation and high quality of coring etc., and is suitable for conducting core drilling on the glaciers at high altitude.
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  Some Advances in Periglacial Environment Studies

  Wang Baolai

  JOURNAL OF GLACIOLOGY AND GEOCRYOLOGY. 1991, 13(3): 273-280. https://doi.org/10.7522/j.issn.1000-0240.1991.0039

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  This paper views some of the advances in the studies of periglacial environment. A large number of ice wedges have been found active in the environment that convertionally would be regarded as too warm for thermal contraction cracking and ice wedge development. Scientists are trying to find the relationship between ice-wedge regrowtb and global change. The recognition of epigenetic and syngenetic ice wedges has long been known, a new type of ice wedges, anti-syngenetic ice wedge, was reported and studied by professor Mackay. Recent research convinces that although ice-wedge pseudomorphs provide unambiguous evidence of former existence of permafrost conditions, it is difficult to define their paleoenvironmental significance with any greater precision. The high pore water pressure that causes pingo uplift is produced by pore water expulsion adjacent to the pingo. All the pingoes contain pore ice, segregation ice, and injection ice, some pingoes have dilation crack ice, and some contain ice-wedge ice. Like ice wedges, no finitive temperature limits can be given for pingo growth because nonclimatic factors such as pingo size, talik size, permafrost thickness, and the time available for pingo growth must be considered. Massive ground ice studies are characterized by the discussion of its origin. Now two main theories for the origin of the thick bodies of massive ground ice known to exist are (1) injection-segregation and (2) buried glacier ice.