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  • 1990 Volume 45 Issue 4
    Published: 15 October 1990
      
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  • SEA-LEVEL CHANGES FROM 1922 TO 1987 IN THE CHANG-JIANG RIVER MOUTH AND ITS SIGNICANCE
    Chen Xiqing
    1990, 45(4): 387-398. https://doi.org/10.11821/xb199004001
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    Because the future global sealevel rise, if real, will exert a great impact on the coastal en-vironment, the Chinese scientists have shown great interests in the sealevel changes along the Shanghai coastal area where the natural environment and society are highly vulnerable to the sealevel changes. The long and early records from the tidal gauges, the geodetic levelling, the annual mean discharge data of the Changjiang River as well as data from other geologic achieve-ments allow the author to make an in-depth study on the issue of sealevel changes in the area. In recent years some Chinese scientists propose that the sealevel has been declining since 1950's along the coast of Shanghai, while other foreign scientists attribute the sealevel rise to the crustal and iso-static sinking. After a comprehensive analysis on the factors affecting the sealevel changes in the area, the author has reached the conclusion of sealevel rise in the Changjiang River mou-th in the past 7U years with the rate about lOcm/century which is comparable with that of g1o-bal sealevel rise. However, the increase of annual mean high tidal level in the same period is remarkably greater, reflecting the estuarine morphological and hydro-dynamical effect on the high-tidal level as the sealevel rises. The evidences suggest that the component of tectonic sink-ing accounts for only 1/3 or less of the regional relative RSL rise. In contrast to the viewpoint of some Chinese scientists that the sealevel has been declining since 1950's, the author finds that the sealevel has shown a rising trend since 1951 with a rate about 2.5 mm/year. It is pro-posed that the sealevel rise after 1951 is a continuation of sea level rise since the beginning of this century. These results will provide a valuable basis for the study of future sealevel chang-es and the long-range decision-making in the regional environment and engineering.
  • THE SPATIAL STRUCTURE AND DEVELOPMENT OF CHINESE URBAN FRINGE
    Cui Gonghao, Wu Jin
    1990, 45(4): 399-411. https://doi.org/10.11821/xb199004002
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    The development of Chinese urban fringe is making way into a new stage. It has the characteristic that urban expansion and rural-urbanization promote or carry on simultaneously. This development way of urban fringe is different from that of developed and the other de-veloping countries. The development and changes of Chinese urban fringe is related to de-veloping stage of industrialization and urb;mization. It could divided into three stage: 1) Agri-cultural type's fringe stage (1949-1959), 2) semi-industry type's fringe stage (1960-1978), 3) industry type's fringe (1979-1989). At present, the main problems of Chinese urban fringe are shown as follow: 1) The con-struction of urban fringe is very disordered because of the lack of effective planning policies and theoretical guidance, so there are a lot of problems in achieving an appropriate balance between urban development and resources and environmental protection 2) Since urban frings is situated in city-country combinative area that is no longer rural but is not yet urban, its plann-ing is not only different from that of rural, various built-up area, but also different from that of rural, various index of planning is urucertain. 3) Urban fringe is also a dynamic zone that is undergoing because of it contact with the city, the contradictory of city's expansion and farmland is very prominent, city's expansion caused the heavy loss of prime farmland of fringe. 4) The social and industrial structure of fringe is not stable, economic system is very complex and economic activities and resources tend to focus on the short-term benefits.
  • FUNCTIONAL STRUCTURES OF SMALL TOWNS IN CHINA—A CASE STUDY OF GUANGDONG PROVINCE
    Chusheng Lin, Lanrence J. C. Ma
    1990, 45(4): 412-420. https://doi.org/10.11821/xb199004003
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    For years, China's urban policy has favored the development of medium-sized and small towns. Chinese small towns have been growing rapidly since economic reforms were initiated in 1979. Two types of towns in Guangdong Prodince are quantitatively analyzed to reveal their functional features. The county towns and market towns are found to be different in the forms of enterprise ownership, employment structure, educational and health facilities, urban infra-structure, and in the absorption of surplus rural labor. Manufacturing dominates the employ-ment of both county and market towns.
  • YU GONG, THE EARLIEST WORK OF REGIONAL HUMAN GEOGRAPHY IN THE WORLD
    Liu Shengjia
    1990, 45(4): 421-429. https://doi.org/10.11821/xb199004004
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    This paper discusses Yu Gong, the earliest geographical work in China and the earliest work of regional human geography in the world, in four respects: delimitation of Jiuzhou, regional study model of Jiuzhou, dialectical relations between transforming of mountains and taming of rivers, and finally dim design of the square-zone model of regional exploitation, It considers that Yu Gong is the first overall development plan oi` comprehensive territorial management in China, the ultimate aims of which is to establish a unitary multinational state.
  • AN ANALYSIS ON THE TREND OF LAND DESERTIFICATION IN NORTHERN CHINA DURING THE LAST DECADE BASED ON EXAMPLES FROM SOME TYPICAL AREAS
    Zhu Zhenda, Wang Tao
    1990, 45(4): 430-440. https://doi.org/10.11821/xb199004005
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    Nowdays, desertification is the impoverishment of terrestrial ecosystems under the impact of man. Land degradation due to poor management has plagued north China for a long time. Since end of 1950's to the middle of 1970's, the area of degraded land has averagely expanded 1560 sq. km annually, and during the last decade it was up to 2100 sq. km in Northern China Re-cently, the total area of degraded land approximates to 197 thousand sq. km. The situation of de-sertificatiou becomes very serious in expleited land of sandy steppe and the vicinity of coal mines. Howerver, a number of typical examples have proved that some measures for land con-nervation are feasible and the process of desertification has effectively been controlled. The potential productivity of cultivated land and pasture has gradually been resetored.
  • ANALYSIS OF SEASONAL CHANGE OF MEAN SEA-LEVEL IN THE CHANGJIANG ESTUARINE AREA
    Shen Jian, Wang Baocan
    1990, 45(4): 441-450. https://doi.org/10.11821/xb199004006
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    The most obvious feature of the short term sia-level variations in the Changjiang estuarine area is the seasonal cycle, which is dominated by the runoff of the Changjiang river and a variety of ocean processes as well as other factors. The monthly mean sea-level changing range is from 40 cm to 70 cm. The changing magnitudes are significant within the estuary and decrease seaward due to the expansion of the runoff and the actions of other factors; consequently, the fluctuations of sea-surface slope varies with different seasons. The highest gradient occurs during the summer and autumn, and the lowest gradient occurs in the winter. Spatial and temporal patterns of monthly mean sea-leve1 of the Changjiang estuarine area have been calibrated by eigenfunction models identifying several distinct factors which in- fluence on the monthly mean sea-level. The most significant factors arc the variations in she runoff, atmospheric pressure and temperature, which account for about 45%, 23%, and 26% of total amount of monthly mean sea-level changes respectively, and the other two factors are abnormal change of the river runoff and the set-up resulting from moonson.
  • RESEARCH OF PLANTS OF TYPICAL LANDSCAPES OF LOW SELENIUM BELT IN CHINA
    Huang Yijian, Tan Jianan
    1990, 45(4): 451-456. https://doi.org/10.11821/xb199004007
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    In the Northeast and Southwest end of low selenium belt in China, two typical land-scapes are studied, that is: the landscape of the coniferous and broadleaf mixed forest in tem- perate zone and landscape of pines yunnanensis forest. other two landscapes as a control are also researched, they are landscapes of broadleaf forest in warm temperate zone and pines massoniana forest in subtropical zone, the former is in the region with out keshan and kachin-Back disease within low selenium belt and the latter is in the Southeastern non-disease belt of China. Results clearly show that the main rlant selenium contents in the typical landscapes are remarkably lower than that in control Landscapes; the soils have a similar tendency, Se levels in soils under the typical landscapes of low selenium belt are lower than that under the control ones. Therefore, the scientific inference of objective existence of low selenium belt in China was further supplemented from aspect of natural plants.
  • A PRELIMINARY STUDY OF THE YELLOW RIVER'S PALEO-CHANNELS IN NORTH SHANDONG PLAIN
    Zhang Zulu
    1990, 45(4): 457-466. https://doi.org/10.11821/xb199004008
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    According to buried deths, the yellow River's pahochannels can be divided into around pareocnanneis (buried depth 0-8 m) and shallow-buried palecechannels (burred depth 8-50 m). They may all be routhly divided into three major paleochannel belts, stretching par-allel with each other from SW to NE in direction.
  • TRANSFORMATION AND UTILISATION OF HOLOCENE BARS ALONG THE COAST OF SOUTH CHINA
    Li Pingri
    1990, 45(4): 467-474. https://doi.org/10.11821/xb199004009
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    The sand bars along the coast of South China were formed in middle and late Holocene according to 105 dating data. They may be grouped into 6 periods. Having analysed the grain size and sediriientary characteristics of the bars in each period, and the regular distribu-tion of littoral bar, baymouth bar, totnbolo and offshore barrierbar, the author, holds the view that the formation of Holocene bars along the coast of South China is closely related to abun-dant source of sand, powerful wave, sea-level close to the present, stable neotectonic movement and the monsoon. The major harmful effects of the bars are: 1. damage caused by wind-drift sand, 2. the baymouth bars woud block the channels. This paper offers a proposal of inter-planting sand-fixing trees consisting of conifer and deciduous with herbaceous and shrub. The major favourable factors are: 1. the abundant placer resources, 2, the multitudinous bar-lagoon bars, 3, a wide space for the development of agriculture, forestry, stock raising and fish-culture, 4. a valuable, land for the exploitation of special economic zone, economic develop-ment district and seaside 'tourism.
  • A METHOD OF CALCULATING EVAPOTRANSPIRATION FROM THE FARMLAND WITH SOIL WATER DEFICIT IN AR1D AND SEMIARID AREAS
    Kang Shaozhong, Xiong Yunzhang
    1990, 45(4): 475-483. https://doi.org/10.11821/xb199004010
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    In this paper, based on the measured data in field, the regularity of evapotranspiration with droughts and soil water deficit conditions has been analysed. Based on soil water balance equation, and comprehensively consideving over the weather condition. Soil moisture state and crop's bioloyical property, we established the mathematics model for the computation of eva-potranspiration from the farmlunds when soil moisture supply was restricted. This model in-volves three parameters, that is, the initial soil water content θ0, the evaporation potential E0 and crop leaf area index LAI, and at the same time, the sensitivity of actual evapotranspira-tion from the farmlands to evaporation potential, the initial soil moisture content and leaf area index were also analysed. Also in this paper, two coefficients in; widely-used penmen formula at present were mo-dified by using the data measured at the radiation stations in Shanxi, Shaanxi, Gansu and Nei Mongol, etc. Finally, the error with the method presented in this paper base been analysed, and the reliability with the model has been evaluated. The result of comparing the estimated evapotr-anspiration with measured evapotranspiration at the experiment plots in Shaanxi and Gansu provinces is that this method has good precisim, it can be used in the arid and semiarid areas in China.
  • SPECTROSCOPIC CHARACTERISTICS OF AQUATIC HUMIC SUBSTANCES IN THE UV AND VISIBLE REGION
    Tao Shu, Cui Jun, Zhang Chaosheng
    1990, 45(4): 484-489. https://doi.org/10.11821/xb199004011
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    Spectroscopic examination of humic substances from river, lake and sea water as well as from river and lake sediments in the UV-VIS region indicated that the E240/E420 ratios of water humic substances differ significantly from those of sediment humic substances. A cluster analysis based on the absorption spectra of the humic substances revealed a similar fact. Con-sidering the hutnic substances from fresh water and sea water respectively, linear relationship between the optical density and the total organic carbon content of the samples implied that a spectrophotometric method (e.g. at 220 nrn) for determination of humic substances concentra-tion is possible.
  • A NEW APPROACH OF CHINESE CHARACTERS OUTPUT IN VECTOR FORM
    SUN YAMEI, SUN YIYI
    1990, 45(4): 490-497. https://doi.org/10.11821/xb199004012
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    The output of Chinese characters in vector from is the main problem of automatically lettering on map. Chinese characters informatio n process can by done by using user's programs, operation system or hardware.