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  • 1991 Volume 11 Issue 1
    Published: 20 January 1991
      
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  • CLASSIFICATION OF ARID CLIMATE IN CHINA AND ITS CHARACTERISTICS
    Xu Shuying
    1991, 11(1): 1-9,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.1
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    In this paper,annual aridity coefficients,annual rainfall and ≥10℃ accumulated temperature are taken as the indexes for the classification of arid climate.On this basis,the arid area is divided into two great types,three patterns and 15 zones.The arid area belongs to continental climate,dry and scarce rainfall.The rainfall decreases rapidly from east(500mm)to west(10mm),and is concentrated in summer.Heavy rain seldom occurs,but once it,occurs,it brings flood and disaster to the people.Wind force in the arid area is large and brings sand-storm.There are less lower cloud and longer sunshine time in the arid area than the humid area.Air temperature is low in winter and high in summer.The ranges of annual and daily air temperature variation are the.largest in China.During rainy season,there are plenty of sunshine and heat resource,which are advantageous to crop growth.
  • EXPERIMENTAL RESEARCH AND PROSPECTS ON LAND EVALUATION EXPERT SYSTEM
    Zheng Xingnian
    1991, 11(1): 10-18,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.10
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    The paper,at first,recalls the history of application of new techniques in natural resources research,shows the significance of application of expert system in natural resources research,and introduces briefly the structure and function of expert system.Then land evaluation expert system is designed and set up,and as an example,land resources are assessed in Zhenwudong Township,Ansai County,Shanxi Province by LEES.At last the paper analyzes and discusses the application prospects of expert system in the survey,classification,evaluation,planning and management of resources.
  • RESEARCH ON INTERPROVINCIAL TRANSPORT LINKAGE IN RAILWAY FREIGHT SYSTEM
    Jin Fengjun, Zhang Wenchang
    1991, 11(1): 19-29,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.19
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    In China railway is a leading transport mode to link different areas,the essential set-up of spatial economic interaction is partly established by railway freight interchange.In the article,the interprovincial freight interchange by railway is studied systematically.The interchange volume was increasing quickly in the past two decades.From 1965 to 1987,it increased from 190 million tons to 73O million tons.The regional transport function of the railway changed.In the 1960s the railway took on mainly inner-provincial freight interchange.But in the 1980s,it took on mainly interprovineial freight interchange.The contradiction between higher increasing rate of interprovincial freight interchange and lower increasing rate of transport facilities is a main reason of transport shortage at present.This contradiction should be solved from the following three aspects:increasing investment,adjusting transport costs,and improving interregional economic cooperation.The obvious spatial features in interprovincial transport linkage are:obvious areal combination,different interaction directions and interaction intensities and so on.In this article,a scientific quantitative method,interaction intensity method is used to analyze the spatial relationship between provincial regions.
  • REGIONAL DIFFERENTIATION OF BASIC PROPERTIES OF PEAT IN CHINA
    Ma Xuehui, Cai Xingyuan, Wang Rongfen
    1991, 11(1): 30-41,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.30
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    According to the investigation in recent years,the proved peat reserves are 5 billion tons.But there are still some peatlands which have not been surveyed and found.It is estimated that peat reserves will be 6-8 billion tons.China’s peatlands are mainly distributed in mountains and plateaus,especially in the Da Hinggan Mountain,the Xiao Hinggan Mountain,and the Changbai Mountain in northeast,the southern part of the Qinghai-Xizang Plateau,the western part of the Yunnan-Guizhou Plateau,having abundant peat resources.Besides,in the Sanjiang Plain,along east and south coasts there are also some peatlands.The basic properties of peat in main regions of China are as follows.In northeast mountains,there are various types of peat,the contents of organic matter and humic acid are the highest(65-70%)and 35%-40%,respectively),pH value is 5-6,decomposition degree is low (below 25%).While in plains and coasts,peat type is single,the contents of organic matter and humic acid are relatively low(50% and 20%,respectively),but decomposition degree is high.In arid zones,the contents of organic matter and humic acid of peat are the lowest(30%-50% and 15%-20%,respectively),pH value is neutral or slightly alkaline.The differences of peat properties in a region are closely related to the change of regional environment since the Holocene.Because peat properties vary with regions,the exploitation and utilization of peat and peatlands vary with regions.
  • BASIC PHYSIOGRAPHIC CHARACTERISTICS OF THE TIANSHAN MOUNTAIN,CHINA
    Wang Shuji
    1991, 11(1): 42-47,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.42
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    The development and evolution of the Tianshan Mountain went through three stages:fold uplift in the Palaeozoic Era,denudation planation in the Mesozoic Era to the Early Tertiary,and fault-block uplift in the Late Tertiary to the Early Quaternary.The distribution pattern of precipitation in the Tianshan Mountain is that precipitation in the west part is more than that in the east part; the north slope more than the south slope;and the interior more than the outer fringe.The pattern of temper ature distribution has an opposite pattern.There are 210 rivers,big or small,in the Tianshan Mountain area.All of them are inland rivers.And most of them originate from glaciers and alpine snow cover area.The distribution of annual runoff volume present a large yearly variation,and a small interyearly variation.The vertical belts of mountainous geomorphology and landscape are all obvious,but the landscape belts of the south slope greatly differ from that of the north slope.
  • CHANGE OF ATMOSPHERIC CO2 CONCENTRATION AND ITS ENVIRONMENTAL EFFECT
    Cao Yinzhen
    1991, 11(1): 48-59,99. https://doi.org/10.13249/j.cnki.sgs.1991.01.48
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    The analysis of climatic change and the effect of atmospheric CO2 concentration shows that climate will tend to become cool in the future according to natural factor affecting climate,but it will tend to become warm according to man’s factor.When climate becomes warm it will get arid in the North America and the Northwest Mediterranean,while in Eurasia,South America and Australia it will get humid.The rise of sea-level produced by warming will have great effect on the area along the coast of China,as well as on all coasts of the world.If natural resources,especially land and wood resources,are reasonably used,most of desertification in east and northwest China will develop toward the ecological environment with high efficiency.
  • DEVELOPMENT AND TREND OF URBAN GEOGRAPHY
    Yao Shimou
    1991, 11(1): 60-66,100. https://doi.org/10.13249/j.cnki.sgs.1991.01.60
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    Urban geography is a young discipline of geography,and an important branch of human geography.The origin,formation and development process of urban geography are discussed.Urban geography originated west Europe and North America.The Central Place Theory proposed by Christaller played a significant role in the development of urban geography.Although China has a long history in urban development,urban geography came into being late.In the semi-colonial society time,urban geography developed at a very low speed because of very low productivity.In fact,urban geography of China began to develop in the 1950s and the 1960s.China has made great progress in urban geography since 1978.Lots of researches have been completed on the function,size,character,spatial structure,development and trend of a city,and urban system.Many important articles and books have been published.They enriched the research scope of urban geography.
  • COMPILATION OF“VEGETATION TYPE MAP OF JILIN PROVINCE(1:50,000)”USING LANDSAT IMAGES
    Bai Yuguang, Zhu Tingcheng
    1991, 11(1): 67-75,100. https://doi.org/10.13249/j.cnki.sgs.1991.01.67
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    “Vegetation Type Map of Jilin Province(1:500000)”is a part of “Vegetation Map of China(1:1000000)”.Much expense and time were saved with the aid of Landsat images.The images of TM have higher spectral and geometric resolution than MSS,which increases the preci sion of image interpretation.According to the vegetation features of Jilin Province,the following four methods for interpreting the images were used:1)the multitemporal analysis of images;2)the analysis of related environmental factors;3)the synthetic analysis of images;and 4)the comparison of adjacent images and cartographic generalization.On the basis of the image interpretation result,the authors built the vegetation classification system,and divided the vegetation of Jilin into 60 formations and 72 mapping units.
  • THE LOESS PROFILE AT SOUTH BANK,CLIMATIC INFORMATION AND LAKE-LEVEL FLUCTUATIONS OF QINGHAI LAKE DURING THE HOLOCENE
    Chen Fahu, Wang Shilan, Zhang Weixin, Pan Baotian
    1991, 11(1): 76-85,100. https://doi.org/10.13249/j.cnki.sgs.1991.01.76
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    According to climatic information,14C dating,spore-pollen analysis and grain size data of Halali loess profile,and the distribution and 14C dating of depositional terrace at south bank of Qinghai Lake,the paper discusses the climatic changes in Qinghai Lake area and the Lake level fluctuations since 10300 years B.P.It is pointed out that there are four relatively warm and humid periods in Qinghal Lake area since the Holocene.They are the periods from 10300 years B.P.to 8500 years B.P.,from 7000 years B.P.to 3500 years B.P.,from 2800 years B.P.to 2000 years B.P.,and from 3500 years B.P.to present time.The optimum climate period in Qinghai Lake area was the period from 7000 years B.P.to 3500 years B.P.when polypodium plants grew luxuriantly around Qinghai Lake,it was quite warm and humid,the average annual temperature was 2.5℃ higher than that at present.The cold and dry periods happerned in 8500 years B.P.to 7000 yearsB.P.,3500 years B.P.to 2800 years B.P.and 2000 years B.P.to about 1300 years B.P..Qinghai Lake level generally tended to lower in the Holocene,but there were four periods of relatively stable high lake-level corresponding to warm and humid periods.
  • THE TYPE,STRUCTURE AND DISTRIBUTION OF ERMANS BIRCH FOREST OF THE DA HINGGAN MOUNTAIN
    Zhou Ruichang, Yang Guoting, Ma Keping, Kong Gang
    1991, 11(1): 86-93,100. https://doi.org/10.13249/j.cnki.sgs.1991.01.86
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    Ermans birch(Betula ermanii)forest can be found in the mountain area of 940-1650m above sea level in the Da Hinggan Mountain of Northeast China.According to the composition,structure and distribution characteristics,the forest can be classified into three types.Ass.Herbsau-Betula ermanii,Ass.Rhododedron dauricum-Betula ermanii and Ass.Vaccinium vitis-idaea-Betula ermanii.Ermans birch forest takes the significant position in the subalpine area and is the main body of the mountain sparse cold-coniferous forest belt, In the Da Hinggan Mountain this kind of forest is not distributed in belt around the mountain top, Because of the special ecological environment,the forest, in this area differs from that in the Changbai Mountaro in the composition and structure.The direct economic benefit of ermans birch forest is not very great,but it so it should can play an important role in water and. soil conservation be protected effectively.