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  • 1996 Volume 51 Issue 2
    Published: 15 March 1996
      
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  • EMPLOYMENT POSTURE AND ITS COUNTERMEASURE IN THE THREE GORGES RESERVOIR AREA
    Chen Guojie,Li Dingjia
    1996, 51(2): 97-103. https://doi.org/10.11821/xb199602001
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    The Three Gorges Reservoir Area is an impoverished mountainous area with a 15.3 million population(1992)and a average density of 282 Persons/km2 where the population has been overloaded.In the area,rural and agricultural Population makes up 90 of the total population, the age structure is in favour of labour force group because the population between 15 to 59 years old accounted for 68. 3% in 1990. The education quality of the inhabitants is poor.The illiteracy rate is 18.85%. The percentage of population over 6 years old who can have a university education is only 0.14%.The labour resource was rich in the area in 1990, Which Was 9.757×106. and it will be 10.22×106 in 2000. Alargenumberoflabourersremain surplusand underutilized. the total surplus labourers are over 3 million which account for more than 30% of the total; most of labourers are engaged in agricultural activities and many labourers take various jobs in the same period as a particular employment form. At present, employment in the Three Gorges Project Reservoir Area is facing threechllenges:urgingsurpluslaburerstobe employedfully, creatingnewemploymentopportunitiesfor Three Gorges Projects resettlement, transforming traditional agricultural labourers who occupy over 90% of the total labour force to city and town, and to the secondary or tertiary sector.The way out of Three Gorges Project’s resettlement problems depends on the sustainable devel opment of the reservoir area, and depends on the strengthening of its economic power and the enlarging of its employment capacity.It would not be a good thinking and a good method to limit resettlement in confined counties, towns,townships, villages and households,and to isolate the resettlement from the systematic and comprehensive development of the reservoir area.We should make great efforts to develop the economy which is the base of employment and resettlement.It is necessary to expand rural enterprises, to develop market agriculture, to enlarge the proportion of the secondary sector and the tertiary sector, to improve the quality of labour force.and to accelerate the process of urbanization.Meanwhile,we should organize labour orce exprot.
  • SOME VIEWSON MIGRATION AND EMPLOYMENT OF THE RESERVOIR AREA OF THREE GORGES
    Wang Enyong
    1996, 51(2): 104-107. https://doi.org/10.11821/xb199602002
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    From the standpoint of a new human-nature relationship approach in geography, the article argues that the mass displacement/relocation of population in the Three Gorges area is essentially a combination of social,economic, and environmental issues.During this process the society should maintain a good relationship with the natural environment and within itself. Farmers to be relocated should not be shifted into the already overloaded traditional agriculture sector.Instead,some newly appeared and created environment like the increased water area,industries like tourism, job opportunities like labor output,and the newly formed social and economic development zone in the growing new towns should play a main role in absorbing the population. Currently when the 9th Five Year-Plan and the long-term plan till 2010 are being considered by the central gevernment, the artical suggests that it is just the time for the related departments to work out a well-organized social and economic development plan for the whole reservoir area.
  • PROCESS-BASED SOIL EROSION AND SEDIMENT YIEID MODEL IN A SMALL BASIN IN THE HILLY LOESS REGION
    Cai Qiangguo, Lu Zhaoxioang, Wang Guiping
    1996, 51(2): 108-117. https://doi.org/10.11821/xb199602003
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    The loess Plateau region, where the study area is located,is one of the most severely eroded regions of China. In reviewing the existing models,we have developed a process-based soil erosion and sediment yield model to predict small basin sediment production in the hilly loess region.In the view of the complex topographical conditions. a wide range of processes and subprocesses of erosion are active, and the associations produce patterns of down slope changes in soil loss which are considerably more variable than the systematic changes generally reconginzed in existing models. This model is divided into three submodels: the hillslope submodel,the valley slope submodel, and the channel submodel.Spatial units considered in this model are parcels of land with general homogeneity in characteristics, i. e.slope zones. For the temporal scale, the model is designed to estimate per storm responses in runoff and soil loss. The specific equations and the algorithm flow chart of three submodels are given seperately in this paper.
  • NUMERICAL SIMULATION OF THE EVAPOTRANSPIRATION PROCESS IN THE SOIL-VEGETATION-ATMOSPHERE CONTINUUM
    Liu Shuhua, Huang Zichen,Liu Lichao
    1996, 51(2): 118-126. https://doi.org/10.11821/xb199602004
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    A quantitative description of the evapotranspiration process taking place among the atmosphere,vegetation and soil is needed for studying air-land interaction and interrelation between the geosphere and the biosphere. In this paper, based on the theory of planetary boundary layer and soil-water dynamics, one dimensional soil-vegetation-atmosphere coupled numerical model is proposed. Parameterizations for upper soil layer and vegetation layer are developed.Through transfers and exchanges of heat and water, the thermal and moisture states of atmosphere, vegetation and soil are linked in a coupled system, in which vegetation is considered as a horizontally uniform layer, and the horizontal differences of soil variables in the system are neglected.It allows the surface to become moist quiukly during rainfall or to become drier than the bulk soil while evaporation occurs.An efficient one layer foliage parameterization is therefore developed that extends continuously from the cases of shielding factor σf=0 and shielding factor σf=0.5.It includs influences of both ground and foliage albedos and emissivities, net radiation, retained water on the foliage, and several other considerations.The evapotranspiration process and soil moisture content in the soil-vegetation-atmosphere system is simulated and the simulated and observed soil moisture contents are compared. The results show that the evapotranspiration can be divided into three stages with the variety of soil moisture near the surface. Soil property and vegetation shielding factor are the most important influence factors in this process.The preliminary results of the experiment indicate that the land surface process model is capable of predicting the thermal and evapotranspiration processes on the land surface and suitable for climate study.
  • A STUDY ON THE STABILITY OF SUBMERGIBLE TIDAL INLETS──A CASE STUDY OF XIAOMIAOHONG WATERWAY.LUSI,JIANGSU
    Yu Guohua, Lu Peidong
    1996, 51(2): 127-134. https://doi.org/10.11821/xb199602005
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    This paper applies research methods of sediment. geomorphology and coast dynamics. analyses the historial development. morden dynamic state and stability of Xiaomiaohong waterway, puts for ward the stability of subergible tidal inlets, and indicates that making use of submergible tidal inlets should comply with the law of natural development and the difference of internalstability.
  • CHINESE HAIR As CONTENT BACKGROUND AND ITS REGIONAL DISTRIBUTION
    Yang Linsheng, Hou Shaofan, Tan Jian’anLu Yilun, Wang Wuyi Zhu Wenyu, Li Ribang
    1996, 51(2): 135-142. https://doi.org/10.11821/xb199602006
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    hair samples from about 200 sample sites are collected. These sites cover 103 counties and different types of natural conditions and are far from cities(or towns) or polluted areas.The hair As are analyzied by hydro-atomic fluorescence spetrophotometry and the data are caculated by computer.The results show Chinese hair As contents are between 0.004 and 9.999μg/g. The median is 0.56μg/g. The arithmetic mean is 0.927±1.213μg/g and the geometric mean is 0.571μg/g.There is no significent difference between sexes and ages. The results of Pelson x2 and Shapio-Wilk W tests show that the As content in the same physical geographical area has a logarithm normal dis tribution.Hair As contents in the South are significently higher than that in the North.The geometric means are 0. 2-0. 4μg/g in medium-temperate zone and 0.4-0.6μg/g in warm-temperate zone. In north-subtropical zone the hair As geometric mean is 0. 767μg/g and in medium-subtropical zone, south-subtropical and tropical zones, it is higher than 1.00μg/g.There is no difference in the same physical geographical zone.Hair AS content in the Qinghai-Tibet Pleatu area is also low(the geometric mean is 0.267μg/g).At last, the standard level of hair As content for chronic arsenism areas in China is also discussed.
  • DYNAMICS OF THE EARTH’S ROTATION-CAUSED EQUATORWARD DRIFT OF CONTINENTAL PLATES
    Jin Mingde
    1996, 51(2): 142-146. https://doi.org/10.11821/xb199602007
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    The dynamics of continental plates has been one of the major subjects in the context of geoscience and the hypothesis on the driving mechanics has been controversial for over a half of this century. Much evidence shows that the plate motion bears a relation to the earth’s rotation in such a way that it is markedly directional, i.e. either vertical or parallel to the rotational axis.Starting from the principles of mechanics, the paper investigates the characteristics of a light body in a rotational frame. followed by addressing the state of a floating body in such a system. It is believed that such model applies utterly to the study of geoplates.One of the basic principles in the theory on plate techtonics states that since plates of different sizes float over the plastic movable sphere. the high fluidity of the matter therein gives rise to the drift of the plates. On account of the rotation, plates are under the effect of a force system.This article Is confined to the discussion of the effects on the plate motion ofthe principal moment acting eastward along the parallel and the dominant vector acting equatorward, the former responsible for the inclination with the head(tail) downward(up-) and the latter leading the center of mass of the plate to translate equatorward,i. e., the plate travels equatorward in a manner of head (tail)downward(up-).
  • A BARACLINIC AIR-WATER DYNAMIC COUPLING MODEL AND ITS APPLICATION IN THE AIR-WATER SYSTEM OF LAKE BIWA
    Zhang Limin, Pu Peimin
    1996, 51(2): 147-154. https://doi.org/10.11821/xb199602008
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    The research work of the coupling model of atmospheric boundary layer with hydrodynamics is an advanced subject in physical limnology. Yukio Oonishi etc.(1975), Casulli,V.and Cheng RT (1992), Zic K, Patterson JC etc.(1992), Zhang Limin etc.(1994) have made many numerical studies in limnology. But all the above works only concerned one of the two factors, separating lake from atmosphere.While studying hydrodynamics, they supposed that the air and temperature fields over the lake were homogeneous. but the hypothesis had much difference from reality.Because of dynamic and thermal difference between water surface and land around a lake, there form character istically inhomogenous wind. temperature, and humidity fields, and these factors have many effectson current and temperature in the lake, and thus forms a special environment. A numerical model coupling a tmosphere with hydrodynamics is set up in this paper,and it applied in the experimental study of Lake Biwa.Some results are got:(1) Whatever (SSW)in summer or(NNW)in winter,there exists a positive wind-stress curl over a lake;(2) In summer the positive wind-stress curl pays an important role to form circulation in a lake and produces a special temperature field corresponding to circulation, lower in the deep water, higher in the shallow water;(3) In summer, the hypothsis of initial horizontal inhomogeneous water temperature has little efftect on the results of simulation;(4)In winter, there is no obvious circulation formed in the lake.
  • A RELATIONSHIP BETWEEN SUSCEPTIBILITY AND GRAIN-SIZE AND MINERALS, AND THEIR PALEO-ENVIRONMENTAL IMPLICATIONS
    Wang Jian, Liu Zechun, Jiang Wenging, Dong Lingxiang, Zhu Mingzhe, Gao Feng
    1996, 51(2): 155-163. https://doi.org/10.11821/xb199602009
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    The relationship between susceptibility of sediments and mineral components and grain-size of sediments is discussed based on the measurement of susceptibility and the analysis of mineral components and grain-size.lt shows that susceptibility of sediments depends on depositional dynamic environments,sedimental source and secondarychange of sediments. If there is no secondary change of sediment since it was formed, the susceptibility of sediments can indicate the changes in sedimental dynamic evironment and sediment source.When sediment source keeps constant the suseptibility can b used as a good indicator of depositional dynamic change.Otherwise,when depositional dynamics keegs constant,the susceptibility can b regarded as a good indicator of the changes in sediment source.The susceptibility of clastic sdiments depends mainly on the content(Pm) of magnetite.Their correlation can be expressed as S=49.18Pm+4.95(10-7m3kg-1. Magnetite,which is a kind of heavy mineral in the sediments, is usually companiate with other heavy minerals in the sediments.Thus, the susceptibility measurement of sediments can help to estimate the content of heavy sand minerals.Because the heavy sand minerals(such as ilmentite,zircon, rutile, monazite) have larger density than quartz feldspar which are the dominant minerals in elastic sediments, the grain-size of these heavy sand minerals in the sediments is about 50% smaller than that of thesediments.So, if we know the grain-size of the heavy sand minerals in a certain region, we shouldfocus on the sediment of which the grain-size is twice that of the heavy sand minerals when we search for placer deposits of these minerals.
  • CALCULATION AND DISTRIBUTIONAL CHARACTERISTICS OF ANNUAL RAINFALL AMOUNT IN MOUNTAINOUS REGIONS OF NORTH CHIAN
    Wang ling
    1996, 51(2): 164-171. https://doi.org/10.11821/xb199602010
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    According to the variation of different parameters of rainfall with height,14 sub-regions in the North China mountainous regions are divided. A study on relations between variation of rainfall and geographical parameters is made. A regression equation is expressed as follows:Pi=a0i+a(1i)ψ+a2iλ +a3ih Where Pi is rainfall calculated,a0iis a constant,a(1i),+a2i,a3i are the partial correlation coefficients,ψis latitude,λis longitude, h is the height above sea level.The average error for calculation is 2. 03% and the maximum average error is 4. 61%.Making a calculation for every 10’ of latitude and longitude and substituting h for λ and ψ in the equation above,we can calculate the rainfall and the maximum rainfall height in a specified sub-region.
  • A STUDY ON THE RATIONAL STRUCTURE OF LAND USE IN THE AREA ALONG THE ABANDONED CHANNEL OF THE HUANGHE RIVER
    Huang Yizhu
    1996, 51(2): 172-181. https://doi.org/10.11821/xb199602011
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    Rational structure of land utilization plays an important role in the improvmentof ecological environment and the sustainable development of regional economy.The area of land is large in the area along the abandoned channel of the HuangheRiver,but the land is used irrationally.According to the development of the counties within the area, this paper studied the types of the land and their suitabilities for agricultural production,analysed the present situations ad problems of land utilization, predicted the necessary areas for various uses in 2000,and proposed a plan and some countermeasures for rationally arranging the structure of land utilization in the area along the abandoned channel of the Huanghe River.(1) Land utilization should b rationally arranged within each county, and the areas of land for various porposes should be regulated.(2) The management of land utilization should be strengthed and the change in land atilization should be controlled.(3) The manner of land utilization should be reformed. There should be a compensation for use of land.(4)Sound laws should be prepared, and farmland should be prorected.(5) The conditions for production should be improved, the farming system should be reformed,and the agricultural investment should be increased.
  • ENVIRONMENTAL EVOLUTION OF MODERN YELLOW RIVER MOUTH
    Li Guangxue, Wei Helong, Cheng Gudong, Zhou Yongqing, Han Yeshen
    1996, 51(2): 182-189. https://doi.org/10.11821/xb199602012
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    We have analysed the data from the lower reaches of the Yellow River and coastalarea measured since 1987 in this paper.The result showed the the river relation (√B/H) became better and better and the deposition distance related to mouth growing into the sea wasonly 20km when the river floods. When the river floods, the channel is deposited seriously due to high sediment concentration of the Yellow River.Because of prominent mouth sand body in the sea, a strong tide current zone has been formed in the delta front since 1982. Lately, the mouth area is deposited slowly due to the silts transported by the strong tide current. hyperpycnal flow and wind wave. In the paper, some advices abut controlling the Yellow River mouth area have been discussed.They are as follows:(1)Because the strong water dynamic environment in modern river mouth is useful to disperse the Yellow River silts into the sea, the lower reach channel should be used for several years.(2)By building the artificial bank along the channel from Qing 3 to Qing 7. the high river bed reach can be controlled.(3)Dredging the higher mouth bar. the danger of channel broken in flooding phase can be decreased.