By analyzing disaster forming mechanism.natural hazards in China can be divided into 20 basic types according to direct factors causing disasters, in which drought, waterlogging, flood, earthquake, landslide and debris are the most serious in China.The macrolandform,especially the three grand relief terraces in China, and the macrolandform-dominated regionalization of natural environment affect the distribution of flood, waterlogging, landslide, debris and earthquake.The difference in natural hazard distribution can reflect the regularities of areal association of natural hazards. The regionalization of disasters should abide by not only geographic principles, but also the principles of similarity and difference in the main types of natural hazards. By analyzing the areal differentiation of Chinese main natural hazards and the intensity of factors inducing disasters based on the Chinese data bases of intensities of the main factors inducing disasters and the data bases of social environment, and using ARC/INFO GIS. the authors compiled distribution maps of Chinese main natural hazards and maps of intensity of factors inducing disasters. Results show that Chinese natural hazards can be divided into 3 regions and 12 subregions.I. Severe hazard region in monsoon plain and mountain in east China This region is located west of seas and controlled by monsoon. The intensity and frequency of drought, waterlogging and flood in the area are the highest in China under the influences of abnormality of monsoon, typhoon and cold wave, and exclusive hazards of oceanic genesis appear here.Microtherm, earthquake, landslide and debris are serious. The area includes seven subregions: I₁ Moderate hazard subregion of waterlogging. flood, microtherm and biological hazards in northeast China; I₂ Severe hazard subregion of drought. waterlogging. flood and earthquake in the plain in east China. I₃ Severe hazard subregion of waterlogging. flood and draught in the middle Changjing River, I₄ Severe hazard subregion of waterlogging, flood, drought and earthquake in the southeast coastal area; I₅ Severe and moderate hazard subregion of drought, soil erosion and earthquake in the Loess Plateau; I₆ Severe hazard subregion of drought, waterlogging, flood, landslide and debris in Sichuan, Guizhou, Hunan and west Hubei; I₇ Severe hazard subregion of earthquake. landslide and debris in Yunnan and west Sichuan.Ⅱ. Moderate hazard region in mountain and basin in dry northwest China This area lies in the inland with dry climate, strong wind and frequent sandstorm. and there is no rainfed agriculture. The main natural hazards are earthquake. flood, drought and windstorm.The area includes three subregions: Ⅱ₁ Moderate and slight hazard subregion of drought, heavy snow and forest fire in Inner Mongolia: Ⅱ₂ Moderate hazard subregion of earthquake, sandstorm,flood and drought in Xingjiang and Gansu; Ⅱ₃ Moderate hazard subregion of earthquake. landslide and debris in the Tianshan Mt. in Xinjian Ⅲ. Slight hazard region in the cold Qinghai-Tibet Plateau Tectonic movement in the region is strong. Earthquake, collapse. debris and heavy snow are intense, but the losses population. This region includes two subregions: Ⅲ₁ Moderate hazard subregion of earthquake, landslide and debris in the southeast Qinghai-Tibet Plateau; Ⅲ₂ Slight hazard subregion of earthquake and heavy snow in the northwest Qinghai-Tibet Plateau.

With the development of computer-aided cartography (CAC) incorporating geographic information system (GIS), electronic mapping system has taken on a new look with rich interactive and analytical abilities. This paper presents an object-oriented model for electronic map designing, and describes its implementing techniques systematically.On the basis of a thorough analysis of a number of cartographic works, such as the National Economic Atlas of China, adopting the object-oriented method, the author provides a conceptual model of electronic maps by abstracting two classes: "map class" and "map layer class" (Fig. 1).Each map has a main topic (usually described with the map name), and this topic may be divided into several sub-topics (themes) including a base map and thematic contents. Each theme is represented by a certain symbolization method with a specific legend, which can be taken as a kind of object "layer". Thus. a map can be considered as an organic entity, named "map object’, which consists of the map name, the mathematical basis, map layers and the relationships among them.The map class should include a series of function members for map designing, editing. querying and analyzing, thematic data and figure output, etc. And thus, a conceptual model of electronic map can be deduced.Going a step further, the author summarizes a numbers of thematic map symbolization methods for economic and social phenomena, and establishes a library of computerized models of thematic symbols, such as "pie" graph, "bar" graph, "percent proportion table" graph, "population pyramid" graph. Based on those above, the author creates a model for electronic map designing, and sets up a series of mapping "templates". With these templates, map features can be visualized automatically with cartographers’ own styles. In addition, a group of essential software resources invoked in mapping templates, such as the map symbol library. the map color library, the method library for cartographic index classification, the symbol-scale building tool, the data capture dynamic linking library (DLL) and the object linking and embedding (OLE) tool, are introduced.Developed in accordance with the strategy mentioned above, the software package MapMagic can produce multimedia electronic maps efficiently and has been successfully used in editing and compiling the Electronic Version National Economic Atlas of China. Through practice, it has been proved that MapMagic, as a thematic mapping software for general purposes, is a qualified method of editing & compiling a variety of electronic maps on social, economic, or natural phenomena.

By using the wind data derived from COADS, of which the mesb is 5白5癮nd the average period is from 1949 to 1987, monthly mean wind stress in the Pacific Ocean is calculated. For determining the wind stress, bulk aerodynamic formula is used in which the drag coefficient is represented by a second degree polynomial, considering the effect of wind speed and stability. The drag coefficient depending on wind speed and stability, which is proposed by Bunker, is selected for analysis. The results show this method is quite good for its precision and convience.In this paper, the zonal and meridional wind stess for each latitude zone and the distributions of wind stress field in January, April, July and October are analyzed. distribution of wind stress corresponds with planetary wind system on the whole. Walker cell in equatorial area and seasonal variation of monsoon circulation in the west Pacific have an obvious impact on the variation of wind stress. There are some asymmetries in the mean zonal wind stress of both hemispheres. Wind stress intensity of midlatitude westerlies is weaker in the northern hemisphere than in the southern hemisphere, and it is opposite in the tropical trades.In the northern hemisphere, in January, the zero line of zonal wind stress is at about 28癗. To the north of this line, the zonal wind stress is positive where the ocean gets momentum from the air.To the south of this line up to the 32癝. the zonal wind stress is negative where the air gets momentum from the ocean. Along the equatorial zone of the west Pacific between 0? 12癝, momentum flux is transferred from air to ocean. In July. trade-wind moves northward. The zero line of zonal wind stress is at about 40癗 in the northern hemisphere and is at about 31癝 in the southern hemisphere.The momentum flux is positive in the summer monsoon regions.The value of longitudinal wind stress is much lower than that of latitudinal wind stress. In January, the dominant wind in the subtropical and tropical north Pacific is from northeast. The meridional wind stress is negative whiers the ocean gets momentum from the dir. Along the east and south coast of Asia continent, the strong northeast monsoon results in a band which has maximum values of meridional wind stress. In July. the wind stress in the east Pacific of northern hemisphere is negative. In the west Pacific, the momentum flux is positive with a maximum in the south China sea and its adjecent seas related to the southwest and southeast monsoon there.

In this paper Cluster Analysis was used for grouping the similar regions of the variability of the Antarctic sea ice, and five regions were obtained based on the Antarctic sea ice extent data of 17 year period (1973--1989). The indices of the polar vortex area and the intensity in southern hemisphere were calculated using of 500hPa monthly mean data in the same period.The analysis of the features of temporal and spatial variations of the Antarctic sea ice and polar vortex as well as their relationships is presented by using statistic analysis. The results show that the discrepancy of climatic characteristics and interannual variability of the sea ice and polar vortex are obvious. They oscillate with cycles of 2 2. 5 years and 5 7 years over most of the regions. The linear trend of the sea ice anomaly reveals that 4 of the 5 regions exhibit a trend of reducing sea ice.The trends of the polar vortex coverage anomaly for all regions are negative similar to that of sea ice, while the corresponding trends of polar vortex intensity are predominantly positive over 3 regions. The above statistical facts is consistent with the effect of global warming.Cross-correlations among concurrent anomalies of the variables are most signifcant from the Southeast Pacific area (e. g., Antarctic Peninsula, region 5) to the South Atlantic area (region 1 ). Lag correlations between them are also closer to the sea ice leading the polar vortex cover and lagging the polar vortex intensity in region 1. The correlations are larger with the sea ice lagging both of the cover and intensity of the polar vortexm in region 5.

The article analysed the spatial division of industry of the Pearl River Delta (PRD) in the context of rapid industrialization both in urban and rural area since the implementation of reform and open-door policy. Industrial output value of 39 industrial sectors of counties and urban districts in 1990 are used. Location coefficient and index of specialization are used to measure the extent of specialization of a spatial unit and its status in the region.The research revealed that the PRD is characterized by its advanced and high-tech industris in Guangdong and China and that the spatial division of industry has been emerging. Most of the cities and counties in PRD have at least 5 sectors in which the location coefficient are larger thanl, and the percentage of uuangzhou’s industrial output value in PRD has droped from more than 50% in 1980 to 23.68% in 1990. This demonstrates that the specialized activities in PRD have no longer been concentrated in Guangzhou.However, the key problem is that a number of the counties/cities in PRD lack highly specialized activities and have similar industrial structure. When measured by using the index of specialization,those counties/cities often have low values. The paper points out that lack of competition from other regions, diversified investment sources and interest groups, decenteralization in economic administration in PRD and weakening of provincial government control/guidance are the reasons contributing to the above problems.To perfect industrial spatial division and to promote industry development in PRD, Guangzhou and Shenzhen should be developed as the industrial innovation centres of PRD. Places outside Guangzhou and Shenzhen should concentrate their industries in only several activities. Government intervening is necessary as integrated development has become an essential issue in PRD.

Lake’ s flow was studied thorourghly and many effective analysis methods were developed both at home and abroad.In areas where flood risk is high, researches on lake flow patterns and the effect of wind on lake water depth are very important in respects of design of flood prevention projects, selectlon of flood prevention creterla, management and maintainance of flood prevention projects and utilization and conservation of wetland in the area. There are many factors reponsible for the lake flow, inc0uding energy, depth of lake water, the roughness of lake bottom and the environment around the lake. Comprehensively taking all these factors into consideration, the paper makes a quantitative analysis on the change pattern of lake flow by means of a two dimensional unsteady flow model with the assistance geographical information system.The lake’s flow propagation model, with the Saint-Venant equations of two dimensional unsteady shallow water, was developed for East Dongting Lake, Hunan Provlnce, China. The model’s parameters(e. g. ground elevation and roughness coefficience). were retrieved from geographic information system, which made the software compacted and universal. The model was used to analyze the lake’s flow motion and assess the impact of wind on flow. The results Indicate that the wind force has an important influence on flow but it is modified by elevation, natural environment, roughness. The water level will be increased by 30.1cm when wind velocity is increased from 6m/s to 12m/s. Following results are got in the study: (1) The geographical information systems has introduced a solution to the probems of selection of model parameters in the analysis of large area lake flow motion. Geographical in formation systems make the processing of model boundary conditions and popularization of the model easy and convenient. (2) The methods adopted in the paper are capable of representing the pattrns of lake flow and the impacts of wind on lake flow. The methods can be used to simulate the process of lake flow motion, to evduate the food prevention function of wetlands(weed land, counter-wave forest) and to identify the sensitive area to wind. (3) Among the so many factors that affect lake flow,the lake bed,the shape of lakeshore and the wind are the most influential factors affecting the patterns of lake flow motion. (4)Further anabsls on the impacts of weed and counter-wave forest on lake flow should be made on the basis of the present research.

Hulu River drainage area is located in eastern Gansu and southern Ningxia, which is west of Lupan Mountain in middle Loess Plateau. The middle Holocene strata were well developed on the first terrace of the Hulu River and its tributaries. The paleoenvironment is established by the analyses of sedimentary characteristics, clay minerals, carbonates and pollens in the deposits ors the terrace. The climate changes remarkablly affected the ancient civilization in the region.The early Holocene stratum can be seen at the bottom of the first terrace, which mainly consists of alluvial loessic deposits. The clay minerals are mainly illites and the pollens are mainly herbs,which shows a relatively dry and cool paleoclimate. There was no ancient civilization during this period in this region.The early-middle Holocene stratum lies in the lower part of the first terrace, which is mainly composed of alluvial and lacustrine silts and clay. The alluvial gravels can also be found in some places, which indicates a warm and humid paleoclimate. A climate change is found by the sedimentary analyses. It was the warmest and the most humid from 8 000 to 6 000 aBP. The contents of kaolinite and montmorillonite are high. The pollens indicates a wooded grassland or a forest flora of coniferous and broadleaf trees. The favourable natural conditions resulted in the appearances andrapidly development of ancient civilizations. The first stage of Dadiwan civilization (7 800- 7 300aBP) shows some relatively advanced characteristics with big ancient communities (based on the size of the sites), appearances of colourful pottery and agriculture. The early Yangshao civilization (6 800- 6 000 aBP) shows some developmental features. The communities were still big and the number of communities was increased. From 6 000- 5 000 aBP the clay mineral association and the pollen spectrum indicate a slighty dry and cool paleoclimate. The technology of production and pottery making of the middle and late Yangshao civilization during this period had some development, the number of ancient communities were also increased but the size of communities was not increased and some were even decreased.The late middle Holocene (about 5 000- 3 000 aBP) stratum mainly consisting of alluvial loessic silts lies in the upper part of the first terrace, representing a distinguish aggradation of loessic silts.The fact that the content of illite increased and the contents of the kaolinite and montmorillonite decreased and the pollen is mainly herbs indicates a drier and cooler paleoclimate. The number and the size of the communities of the Changshan civilization(4 800-4 200 aBP) decreased. Thete were some cave like residences. The technology of pottery makinghad some retrogradation. The communities of Qijia civilization(4 400-3 900 aBP) were widely distributed but the size of them were very small indicating that the civilized area increased but the production of per unit area decreased, and also the proportion of animal husbandry increased. The ancient civilization from 3 900-3 300 aBP has not been found out yet. The Shiwa civilization(about 3 000 aBP) was also very limited in scale. All of these are because of the deterioration of the paleoenvironments during this period.

Well irrigation and well drainage" was adopted to ameliorate saline-alkaline land in the 1960’s in Feng Qiu and Yucheng, and "pumping saline-water and suppling fresh water" was used to improve saline-alkaline land in the 1960’s in the northern part of China.On the bases of the specific conditions in Bei Qiu in Yucheng City, we adopted a method of intensive pumping and irrigation to ameliorate saline-alkaline land. The improvement is distinct, and the treatment period is shorter.After intensive pumping and irrigation, the ecological conditions can be long maintained by spreading manure, intertilling and loosening the soil, covering with crops at all seasons, salt content in the cultivated layer is less than 0. 2%, and crops grow very well for 4 years.It is clear that irrigation can leach salt of soil, spreading manure and nitertilling-loosenning the soil can improve root condition. Pumping saline water and Levelling of land can strengthen the improving effect.

Tourist market involves the supply market and demand market. It is significant to maintain the balance of tourist supply and demand. This paper discusses the law of regional distribution and dynamic balance of tourist supply and demand. The author also defines the spatial models of tourist supply and demand.First, based on case studies, a new concept, tourist threshold population, is defined. The threshold population size of a tourist destination is the population size of tourists visiting the destination when input of tourism is equal to output.Secondly, a demand model is given. From the demand model, we can understand easily why the tourism in metropolitan areas often bring higher income than in remote regions.From the supply and demand models, tourist destinations can be divided into four types and conclusions on the space linkages of tourist supply and demand in the four types are drawn. The four types are listed as follows:1. tourist destinations are located in the core cities of metropolitan areas;2. torist destinations are located in the suburbs or outskirts of metropolitan areas;3. tourist destination are located beyond metropolitan areas;4. tourist destinations are located in remote regions.In the first situation, the supply and demand of tourism are overlapping in space, and the marginal profit of tourism is the largest. When the distance between a tourist destination and a core city increases, the marginal profit of tourism decreases.

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.

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.

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.

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 σ^f=0 and shielding factor σ^f=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.

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.

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.

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-).

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.

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(P_m) of magnetite.Their correlation can be expressed as S=49.18P_m+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.

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:P_i=a_0i+a(_1i)ψ+a_2iλ +a_3ih Where P_i is rainfall calculated,a_0iis a constant,a(_1i),+a_2i,a_3i 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.

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.

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.

Since China opened the door to the outside world in 1979.China’s coastal areas have succeeded in developing its outward oriented economy.Foreign trade and foreign investment have played an important role in its economic growth.Certainly,its economic sustainable development will be influenced by the changing tendency of the world economic pattern.In the end of 1980’s,a series of significant changes happened in the world.The new world structures are taking shape now,the characteristics of which are"triangles" and regionalizatlon,that means triangular structure── developed countries, new industrializing countries and regions,developing countries, three big poles── America, Japan and Germany, the regional economic blocks── Northern America, Western Europe and Western Pacific region.Since the middle of 1980’ s, the world foreign direct investment(FDI) has increased in an unprecendented speed way. From 1985 to 1990, the growth rate of the world FDI in name was 34%per year, which enormously exceeds that of the world exports value(13%) and that of the GDP of the world(12%) in the same period.It is very significant for developing countries to improve their investment environment and to absorb FDI.In 1990’ s, nevertheless,international capital shortage will be a long tendency because the capital demands greatly surpass the capital supplies.So,international competition in attracting FDI will be very fierce.Being influenced by international economic regionalizatlon,the basic tendency of the world capital flow in 1990’s will be in a form of cross──investment.The developed countries are the most important investors.Also, they are the most important absorbers of the world FDI.The developing countries only share a very little portion.Fortunately,the Asian "Four Small Dragons"(AFSD) have been a noticeable forces in international investment fields, which changes the traditional global investment patterns.Because of Geographical position and ethnic features,AFSD’s investments mainly concentrate on China’ s mainland and on some south-eastern Asian countries.In the future,overseas macro-background problems for China’ s coastal areas are how to deal with four hierarchies’ relationship. which are the first hierarch(Western Europe,Northern America,Eastern Asia),the second hierarchy(China,Japan,America),the third hierarchy(china’s mainland,AFSD,some South-eastern Asian countries),the fourth heierarchy(China’s mainlad,Taiwan,HongKong).The characteristics and the tendency of absorbing FDI for China’s coastal areas can be summarized as follows:(1) FDI is mainly from AFSD.Gradually,such developed countries as America,Japan and Germany,will increase their investments in the region.(2) Investment fields are mainly manufacture sectors,especially labr-intensive industries.Step by step,hige-tech items from western developed countries will increase.(3) Investors are mainly medium and small slied enterprisers.By degrees,multinatlonal enterprises’(MNEs) investments are increasing.(4) Investment location mainly concentrates on the south-eastern coastal areas. Progressively,FDIs will push towards the central and the northern coastal areas of China.Generally speaking,MNEs have advantages of high technologies.China strongly desires for MNEs’Investments in order to raise its industrial technological level.Because of the unfavorable soft investment environment,MNEs’ Investments In China’s coastal areas are very limited.Joining the world trade organization will be a very important measure for China to absorb MNEs’Investments.Accordingly,China will have to cut down its over-high tariff and to remove its non-tariff wall.If so,the opportunity for south-eastern China will surpass thechallenge for its competitively advantageous industries.Reversely,the challenge for northern coastal areas of China will surpass the opportunity for its competitively disadvantageous industries in the world industrial division.

Historically,China has experienced numerous climatic changes or variations.In the last hundred years,it seems that China’s climate has become generally warmer and drier.Temperature increases have been Particularly notable in the north,with less evidence of changes in South China.Records show an obvious drying trend in eastern and northwestern China since 1910.Estimations for the future climatic change include:(1) Most Parts of China l be warmer in 1990s, cooler during 2010 2030,and warmer again after 2040.(2)The greenhouse warming would strengthen the warmer period,hence the average temperature will ne in the next century,about 2℃ higher during the warmest period than that at present.In the warming process,however,there would be fluctuations in a temporal scale of 20 30years and with a extent of 0.5 1.0℃.(3)The precipitation will decrease in the east and increase in the west.China’s agricultural vulnerability to climatic change is amplified by the high degree of dependeuce on a diminishing agricultural resources base.DEspite its vast size.China is poor in agricultural resources per capita,especially cropland and water resources.On the other hand,the population will increase.So the cropland per capita will be even less.Furthermore,the productivity of cropland is hindered by water shortages.This moisture constraint on food prduction is likely to be aggravated by climate change.Investment and technology are important in adapting to climatic change.However,China’s prospects for investment and technological development in agriculture are relatively modest.There fore,the Capital put into agriculture is limited.With huge rural populations but relatively scarce scientists and technicians and with inadequate equipment in agriculture, China has very limited prospects for technological adaptation to climatic change.Most researchers agree that global climate change would impact greatly on Chinese agriculture,whatever the regional climate change may be,because Chinese agriculture is already sensitive to climate-related conditions.At least,the followings will occur:(1) A loss at least 5% of overall agricultural production as aresult of warming,because of increased evaporation.wind erosion of soil,drought,and increased frequency of typhoons.(2) Several forest species face serious losses and some forest areas will be converted to steppe,covered by non-productive hot or warm-natured shrubs and grasses.(3) Significant damage to coastal areas from even a moderate sea level rise would occur,with extensive flooding and destruction of existing salterns farm-land and fishery farms,that large food sources for coastal China.In regard to deltas,where the most productive land is found and the densest population and the richest infrastructure and settlement in China are located,half of the Zhujiang River-Delta,abut 3500 square kilometers,might be inundated,and wide scale flooding is projected for more developed areas of the Changjiang River and Huanghe River deltas.Thus the food production in China will be challenged greatly and this will happen at a time when Chinese population and living standards are increasing greatly.The future national security of food sufficiency would be in more uncertainty.The feasibility of production may shrink,the flexibility of resource-use would be less,and the vulnerability would be increased.Concerns over potential agricultural impacts of clmatic change have promoted consideration of adsptations.The question of adaptation has been approached in two ways. First,It is likely that farmers and rural communities,when faced with changed climatic conditions,will adjust their practices.Thus,any estimate of agricultural implications of changes in climate needs to consider possible "spontaneous" adaptive strategies,and the prospects for their adoption.Second.in the face of crop losses or new production opportunities associated with climatic change,public authorities may promote adjustments in the nature and organization of agricultural production,in order to minimize climate-related losses and to realize potential be

Since the reform policies commenced in 1978,overseas investment in China has increased rapidl HongKong direct investment(HKDI) comprises a large share of this growth.This raises a question in terms of the regional disparity of the investment.Namely,why do some areas have large concentrations of overseas investment while others are unsuccessful in attracting outside money? It is clearly related to the locational behaviour of the investors and to the environment of the areas concerned.Therefore,the research intends to analyze changing spatial patterns of industrial location and characteristics of the investment behaviour of HongKong-based companies.This has been achieved through a number of surveys and interviews with HongKong business managers.Since the research examines China’s investment environment from the perspective of demand side,the results are expected to be more helpful to increase mainland Chinese in further understanding the spatial investment behaviour of HongKong business.This will benefit both investors and local people,and especially assist the less-developed areas of China in attracting investment.The study indicates that regional differentiation of HKDI in China was enlarged in 1980s and has ben reduced since 1991.The regional changing patterns can be summarized as:concentration of HKDI in the Southern China and the coastal areas has been replaced by the trend of moving Northward and Inlandward after 1989.But in terms of manufacturing industry this trend has not appeared by now.The changing patterns are clearly related to the behaviour of HongKong investors.The survey shown that"enjoying lower Production cost" is the most imPortant motive for Hong Kong industrial investment in China.In consequence,"close" to Hong Kong,"cheaper labour" and"favourable policy" are major factors factors determining investment locations.This behaviour,together with most investors’ habit of not doing comparison study for their locations throughout China,can well explain that Guangdong attracted most Hong Kong investment in 1980s.As the cost increasing in Guangdong,some companies started to look for Non-Guangdong locations for their investment at the end of 1980s.This trend has been proved by the possible investment locations specified by surveyed companies,which covers 22 provinces,municipalities and automonous regions.The most attractive locationsinclude those in Guangdong,Shanghai and Beijing.In addition, Hunan.Fujian, Hainan,Sichuan, Zhejing, Shandong,Jiangsu, Tianjin and Hubei are optimistic in future investment.Form the behaviour analysis of Hong Kong invested companies,some suggestions are made for regional governments to attract investment:a)To increase accessibility and reduce transport distnce:b)To try every possibility helping investors to reduce the overall cost;c) To make policies stable and implementation thoroughly d)To improve local manager’s ability to enhance localizating management;e) To let the potential investors aware of the regional environment by using various media.

There are many mountains and vast plateaus in the western region in China.Owing to the influence of vertical zonality,It is difficult to divide the climatic belts.But the vertical climate is established based on the base vertical climatic belts that have the characters of latitudinal zonality.Therefore,the divided western sub-tropical thermal belts are latitudinal zones.Thereafter,YunnanGuizhou Plateau and Jinsha River Velley should be in the middle sub-tropical zone.The latitudinal zonality is destroyed by the Tibetan Platearu.Therefore,there is a boundary of western sub-tropical zone which is located on the eastern side of the Tibetan Plateau.It is a boundary on the north,the middle and the south of the sub-tropical which runs into the Tibetan Plaleau.But there is not a transitional zone between the sub-tropical belt and the Tibetan Plateau.The method of dividing the western subtropical is advanced in this paper.

Climate is a slowly-varying equilibrium system due to the interaction of atmosphere,ocean and land under the effect of the solar radiation.As the basic energy resource of the atmosphere motion,solar radiation is a decisive factor with important impacts on climate formation,while the factors of underlying surface,such as land-sea distribution,topography and properties of land surfaces,directly affect the spatial and temporal distributions of solar radiation,and consequently affect the features of general circulation in the earth-atmosphere system and the distributions of global climatic fields.So,local climate can not be parted from specific underlying surface conditions and geographic environment.Recently,many scientists studied the causes of the climate change and tried to predict the tendency of the climate variations by various methods.It has been found that climate fluctuation is affected by tropical sea surface temperature anomalies,the advance and retreat of the polar ice and concentration variations of aerosols and absorption gasses (such as CO₂ and other trace gasses)in the atmosphere.In the past,it seems that people overemphasized and exaggerated the function of the orographic height on the climate,while paid little attention to the influences of land-sea distribution and properties of land surfaces,and the effects of each underlying surface factor on the process of the climate formation and variation have not been studied systematicaly.In this Paper,we discussed 3 problems:(1)effects of land-sea distribution on general circulation,(2) climatic effects of topography,(3) impacts of land surfaces on climatic change.A coupled general circulation model in a zonal domain belt (60癝 to 60癗) is used to simulate the development of general circulation and the climate variations in summer.In the simulations the earth is assumed to change from a globe with a homogeneous surface to that with land-sea distributions,the global land is set to be flat with gradually uprising to the real topography.The results reveal that without land-sea distribution the climatic fields are zonally uniform,the wind fields in the atmosphere show the properties of planetary wind system and three-cell circulations.i.e.the Hadley,the Ferrel and the polar circulations,With land-sea distribution,in the north hemisphere in either the upper or the lower level atmosphere.the circulation status shows a zonal two-wave structure which is consistent with the land-sea distribution.So,land-sea distribution may be the fundamental factor which forms the modern general circulation pattern.The Tibetan Plateau topography intensifies the,Soil desertization strengthens the pressure system over the continent,increases the surfacial and atmospheric temperatures and the extent affected in the continental area,The topography and the types of land surfaces have the effects with a comparative order on the climate variation,but both of them can not change the fundamental pattern of the general circulation,Any factor in the climatic system will affect the sensitivity extent of other factors,Therefore,in order to simulate the paleoclimate during the geological periods,besides the plateau topography more factors should be considered,especially the variations of land-sea distribution and the types of the land surfaces.

Scientists have developed tectonic geomorphologic classifications in different ways based on plate tectonic theory.This paper deals with the ideas and methods of the geomorphological classification based on plate tectonic thory in the Geomorphologic Map of China Sea and Adjacent Region(1:8600000).This classification has three characteristics:1.Plate tectonic theory was used In the first order classification,and the divisions of continental landforms and submarine landforms were not accepted as units of the first order classification.2.According to the modern plate environments,intraplate and plate margin geomorphologies were classified.The modern and the plaeo-plate margins were not considered as geomorphological types in the same order.3.The horizontal movement was emphasized and the intraplate organic classification was used for dividing mountain types.The 12 first-order global geomorphologic types were divided.The studing areas has three first order units:the intraplate continental landform,the continental margin trench-arc-basin and the oceanic-margin trench-arc-basin landforms.They were further divided into 11 second-order types and more than 20 third-order types.

A60cm depth core of about 450 years old was drilled from Elson Lagoon in Barrow, Alaskan Arctic(70°21’N, 156°40’W)in the August,1994.The drilling site was located in a water Of 2m deep and was 1.5km away from coast.About 50 samples with intervals of 1-2cm were taken from the core to analyze the micro-fauna.Based upon the distribution properties,8 genera and 13 species of foraminifera were identified and three assemblages were distinguished:(1) At the lower part(35-60cm) of the borehole AB-67 Assemblage Elphidium orbiculareElphidium clavatum were distributed,in which the in which the dominant species were Elphidium orbiculare,E.clavatum, E.bartletti,Buccella frigida,et al.,without gluey shell foraminifera;(2) Assemblage buccella frigida-Ammotium cassis were found in the middle part(19-35cm)of the core;(3) Assemblage Elphidium asklundi-Elphidium excavatum alba were in the upper part(0-19cm)of the core. 9 general and 9 species of ostracoda were identified too,which can be divided into two assem blages:(1) Assemblage Limnocythere sp.-Normanicythere leioderma which were distributed In the lower section(31-60cm)of the core and were characterized by existence of both maritime and ter restrial ostracoda;(2) Assemblage Cytheromorpha macchesneyi were distributed in the upper section(0-31cm)of the core.Based upon the assembled characters and ecological features of the microfauna in the borehole AB-67,environmental changes in Barrow,Alaska in the past 450 years can be recognized as follows:(1)Before 1740 AD(e.g.from the mid of the 16th century to the 18th century),It was rela tively cold and in a low sea level stage,which were concluded by the existence of both marine and non-marine micro-fauna.The non-marine ostracoda indicates a lake-stream deposition environment with fresh-brackish water.The marine micro-fauna was likely eurythermal and euryhaline forms,so the drilling site was estimated to be located at a river mouth or in a tidal zone near the coast and the sea level might be 2.5m lower than that of the present between the mid-16 century and mid-18 cen tury,which coincided with a little ice age.(2) From mid-18 century to mid-19 century,it was becoming warmer and a slight transgres sion commenced.(3)From mid-19 century to present,it as warming,accompanied by continuous transgression.

A study is presented of trend testing of Tibetan snow cover variation by using daily snow depth records at 60 primary climatic stations covering the period from 1957 to 1992.A statistical model consisting of a trend plus serialy correlated noice is fitted to the areal and point time series data to test for trends in snow cover variation.The results of three trend estimates based on difference of average.least squares fitting.and slope AR(1) process imply that the increase in annual snow depth is a systematic development as evidenced by the presence of a deterministic trend.The increase of snow depth is almost omnipresent over the Tibetan plateau.However noable exceptions are the Yarlung Zangbo valley to the west of Lhasa,and along highway between Da Qaidam and Beilu Heyan.further examination of year-to-year fluctuation of snow cover over the Tibetan plateau and surface air temperature in wintertime over the northern Hemisphere during the period between 1957 and 1992.reveals a positive relationship between the two.This association tends to contrast sharply with reduced extent of snow cover in extratropical Lands in late 1980s,but coincides with the recent increases in Antarctic and Greenland snow accumulation.

Remote sensing,GIS,GES.which are excellent methods and GRSIMs which are geographyphysics-mathematics models to study geographical phenomena and theory,have to develop in advance of mathematics in the modern geography,Remote Sensing,GIS,GES,came to computerize,so GRSIMs must be computerized.GRSIMs propel the geography forward from the spherical structure to the independent factors,It is the same as biology forward from the cellular structure to molecular biology,Certainly,different branch of science has different characters and different developmental steps.Right now,high technology-space technique and computer technique bring the opportunity for devdoping geo-science and astronomy.Remote sensing,GIS GES,GPS(Global Positioning System),telemetry.and satellite communications are going to everywhere,especially In geograPhy,In recent decade,we have founded new way of geographical theory which is established on the independent factors and is named as Geographical Remotes Sensing Information Models (GRSIM).There are two kinds of GRSIMs,One is based on the independent varables and the other is based on the independent knowledge of geography,Based on the independent varables,GRSIMs are pure quantity caculation,for example,debris flow veloslty equation,concentration of suspended sediment,soil moisture,soil erosion,thermal diffusion,etc.Based on the independent knowledge,GRSIMs are combined by quality and quantity with geographical information coded models (GICM).For example,soil erosion in small scale1:5 000 000 maps,etc.Based on DOS and WINDOWS,GIS software have been established on micro-computer which is named MCGIS. The MCGIS is a new design with Remote Sensing Information Models,

The distinction between city and countryside in China’s spatialeconomic structure is disintegrating as industrial development in urban and rural regions are complimenting and infiltrating each other.A complex multiplicity of factors are examined to determine how they have influenced the spatial proliferation of non-agricultural activity in Kunshan at the edge of Shanghai.Analysis of the conditions and circumstances of rural industrial development peculiar to the region reveals certain contradictions.Although it may be sensible,even preferable.to locate industry based on the factors highlighted in the conventional models of industrial location.local level realities militate against this.Thus the conventional wisdom of established theories of industrial development and urbanization does not adequately explain the emergence of certain relatively productive "mega-urban "regions.The resulting theoretical reformulations have culminated in a framework for planning and policy formation embedded in the concept of“metrofitting”.This artical critically evaluates metrofitting in the context of the spatial economic transformation observed in the lower Chang Jiang delta.Findings from recent field investigations fundamentally challenge assumptions regarding the processes which underlye this transformation. More appropriate regional development strategies are therefore.suggested.Moreover the analysis demonstraies that general conclusions about China’s mega-urban regions must rest upon a detailed understanding of the mechanisms of local economic change.

The Geo-system is an open and complicated system. This complexity origins from the geographic environment including natural environment and economic environment. However geographic space is a nonhomogeneos space. Furthermore.the nonhomogeneity of regions exists so absolutely that innovation diffusion in geo-system is restricted by geographic environment,as there is a great deal of differences between regions which have different natural,economic and social qualities.Then, there is no doubt that the diffusion process of any innovation is in nonhomogeneos space.Spatial diffusion relates to not only distance but also nonhomogeneity of regions.A significant body of spatial diffusion theory was formed as a result of the work of T.Hagerstrand and others. Spatial diffusion research is of importance in understanding the spread of diseases, ideas,business, products and people from initial origins through time and space. But. existent diffusion models have been found to be parsimonious and inflexible in solving practical problems, because the T.Hagerstrand’s models were based on the homogeneos space and the diffusion of geographic environment was ignored. It is considered that innovation is composed of infinite and noncontinuous small diffusion medium and the third dimension is included in space due to nonhomogeneity in this paper.We transfer the movement of innovation in two-dimensional space into a great deal of random medium movement in three-dimensional space.The random movement may be described by the Kolmogorov diffusion equation. By means of the spatial diffusion equation, we can derive the centers of isotropic diffusion,anisotropic diffusion, multiple diffusion and the dynamic diffusion equation in nonhomogeneos space.

Snow cover is an improtant factor influencing animal husbandry in winter in the north part of China. The relationship among grass height,snow cover area and snow depth is a key to determine the harmfulness of snow disaster.So.using NOAA/AVHRR image to get the snow cover area and using snowfall and topographic indices from DEM to measure snow depth will provide a practical way to monitor large area snow disasters. In this paper,Xilingol League in Inner Mongolia is selected as a study area,and following problems are studies:1.Clouds and snow surfaces have similar characteristics in both visible and infrared spectra.How to identify them in determining snow cover area is necessary but difficult. Multi-temporal composite technique in processing NOAA/AVHRR image is presented and testified as an effective method in this paper.2. Two topographic indices of wind sheltering fetch and relief from DEM are put forward,which are main factors influencing snow depth.Then the model of the relationship between snow cover depth and snowfall and above indices is built,and the distribution pattern of snow cover depth is revealed.3. By overlaying snow depth map and grass height map. the harmfulness of snow disaster is evaluated in the study area.

With the development of GIS applications.GIS system integration has been the most active field in system software development.However, specialized process models have been developed,which are independent of GIS technology, and they are as complicated as GISs. Moreover.the data model of GIS still lacks spatial-temporal component needed for environmental simulation. Although it is very clear that integration is the key to GIS applications.the obstacles in integration still exist.This paper deals with some theoretical problems in system integration: concepts, problems, architecture. and methods and steps for integration.The author also introduces the contents of system integration and the considerations for engineering projects by combining the achievements obtained from two key projects (Study on Flood Damage Monitoring and Assessment Techniques and Integrated Information System for Major Disasters Monitoring and Assessment), and puts forward a new method, namely, dynamic linking, for GIS integration. Compared with the peer-to-peer or embedded architecture, dynamic linking is more flexible, more open, and more efficient in operation, However, Import/Export capability, the core of peer-to-peer architecture,is still one of the most important component of an open and dynamic integrated system because of the greatest differences between the data structures of process models and GISs.It is better for us to use open concept and object model to improve the Import/Export as an embedded function of GISs.

Study on the spacial bhavlor of tourists is one of the important research fields of tourism geography.On the basis of much on-the-spot investigation,the author,taking Huangshan,Jiuhua and Quyun Mountain which all are national mountain resorts for examples,expounds two questions:(1)making use of spacial use curves of resorts to analyse movable space of tourists in the three mountains,we discover the value of mountain resorts affects the movable space of tourists.Generally,the higher the value, the wider the movable space and the more complicated the movable spacial configuration.As time passed, the movable space changed. As for Huangshan Mountain,the change of movable space of tourists is beneficial to the tourism devdlopment.(2) Through the contrast of travelling spacial behavior between tourists in Huangshan Mountain and ones in Yellowtone Park,we discover,with the lift of the social and economic Positions of tourists and the increase of distances from the residence of tourists to the resorts,the travelling spacial behavior of the tourists tends to complicate.

A mathematical model of three-dimensional wind-driven current is developed with the consideration of local wind system in Taihu lake. The simulated results on the current circulation are more consistent with the observed data, especially on current speed, in comparison with the simulation with respect to two-dimensional models. In addition, it shows that the topography of the lake basin influences on lake circulation, and the existance of the Xishan Island strongly enhances the current speed in the area between Xishan and Dongshan Islands. The convergence field in Taihu lake induced by different wind directions which influence directly on the distribution of the alga in Taihu lake is computed and analysed. Considering the two bays in the north area of Taihu lake, the convergence field can be divided into three patterns: (1) convergence patterns under S and SW winds: (2) divergence patterns under N and NE winds; and (3) convergence and divergence patterns under W, NW, E and SE winds.In terms of the simulated results. the concentration of blue-green alga in Taihu lake can be known roughly.In conclusion, three-dimensional model is better than two-dimensinal model in simulating wind driven current in large shallow lakes such as Taihu lake. The long corridor between Xishan and Dongshan Islands in Taihu lake is very important to the formation of the lake circulation. The three patterns of convergence fields which result in the different distributions of the concentration of the alga are classified in the paper according to the different wind directions.

It was explored that the drying trend of eastern China were divided by abrupt changes (280’s,880’s and 1230-1260’s).The changes of population during the last 2000 years were delineated and the percentage of people living in the northern part was calculated (table 1).It shows that during the early time,the population in the northern part got the higher percentage than that living inthe southern part.Then the percentage dropped rapidly at the 13th century, and had not recovereduntil now.Table 2 gives the percentage of population of provinces showing the population constractbetween the west and the east.It shows that before the 13th century the Shanxi/Shaanxi (westernpart) were almost the same with the Jiangsu/Zhejiang (eastern part),but afterward the easternpart got higher percentage than the western part.Cultivated land and tax were adopted here toshow changes of economy.Table 3 shows the percentage cultivated land and tax of the northernpart.Same conclusion are given as that shown in Tables 2 and 3.It hints that after the 13th century,a new geographical structure was set up.The relationship between the changes of demography (and culture) with the climate are tried toinvestigated in this paper.It has been discovered that the central government often lost their rulingover this country during the cold epoch.

The system of northern Jiangsu lowlands has its particular states and structures due to the seariver interaction.It is a low-lying plain with a mean elevation of about 3 metres above sea level.Its slope gradient is about 0.2‰-2‰ and the mean gradient of channels’ water stage is 0.004‰. By making the digital elevation model and analyzing the Quaternary sedimentary facies,the system ofnorthern Jiangsu lowlands is divided into three parts: the ancient lagoon low-lying plain of Lixiahearea, the marine plain along coastal area and the Changjiang river delta plain.The sea level rise willhave severe effects on the system, which will be more frequently endangered by flood and water logging.Through analyzing the states and structures of the northern Jiangsu lowlands system.this paper studies its complex responses to the sea level rise, and gives the measures adapted to the sea levelrise.

The framework of the young earth system science as the basis of strategies for sustainable development is discussed in conjunction with a brief account of its rise and development from studies onthe climatic system. There is the need for collaboration across the natural and social sciences. Integrated assessment of global and regional environmental changes is indispensable. When what can bedone to moderate or mitigate the impacts of these changes is under consideration.With regard tosustainable development, the time span is generally kept within one or two handred years.and theearth system involved consists of land, oceans and atmosphere together with the exchange of matterand energy across their interfaces.While land is the centre of socio-economic development and thescene of most complicated natural conditions,it lags behind in earth system research. Geographersare urged to make up the deficits.

A sysposium on studies of earth system science and sustainable development was held in Beijing between March 9-10,1996. It is initiated by Professor Huang Bingwei, for he suggested setting up the territorial system science as the theoretical base for the sustainable development in China.Prof. Huang Bingwei shares the vast experience which he has gained by his studies, and he identifies lesson about earth system science and sustainable development.Numerous participants came from various universities, institutions and science foundations.