Geocomputation, as one of the cores of geographic information science (GIScience), focuses on methodological problems, including modeling, algorithms, computational systems, and the general methodology in the field of GIScience. With the rapid development of GIScience in China, five trends of geocomputation are concluded and presented respectively: (1) Geo- data mining refers to the means of discovering geographic knowledge concerning geographical problems in ways of model processing and computation of various kinds of data; (2) Spatial operational research is widely applied to the field of geography, with its algorithms simpler and more precise and its accuracy higher; (3) Multi- Agent System(MAS) has become the third important method of geography research ranking after induction and deduction; (4) Quantitative computation in discrete space turns into the necessary fundation of computation in geographic space; (5) Geographic ontology is essential to the progress of GIScience as well as the development of geography in general. Some new direction have appeared on geocomputation, they include: 1 computational pattern, as is, Cooperative Computing, Pool Computing; spatial computation complexity; and mappattern recognition.
Flood risk assessment is the first step in the flood risk management. Flood risk regionalization, which can help understand the distribution patterns and internal rules of flood risk clearly, is developed based on the flood risk assessment. Firstly, the authors explain concepts of flood risk concerned in order to clarify and standardize them. Secondly, this paper reviews the methods of flood risk assessment and flood risk regionalization. The primary methods of flood risk assessment are geomorphological method, hydrological and hydrodynamic modeling method, system emulation modeling method, historical flood disaster data based method, palaeoflood and historical data method, remote sensing and geographical information system method, system analysis method based on the mechanism of flood, and etc. After a brief summary of the researches on flood risk assessment and flood risk regionalization, some perspectives on flood risk assessment and flood risk regionalization are put forward, such as the data base of flood risk research, temporal- spatial scale of assessment, theories and methods of regionalization, technical measures.
As one of the most widespread vegetation types worldwide, Grasslands cover nearly one - fifth of the world' s land surface area and play a significant role in the global climate change and biogeochemistry cycle. However, a large area of grasslands in the world has been faced a serious problem- degradation and desertification. One form of desertification is the conversion of homogeneous grasslands into shrub- dominated ecosystems and shrubs encroachment has become a widespread phenomenon in arid grasslands and savannas over the past century. The transition has greatly affected ecosystem structure and function in semiarid and arid ecosystems. Overgrazing, regional climate drought and natural fires are the critical factors controlling shrubs encroachment and development. During the process of shrubs encroachment, the wind erosion and water erosion of soil will be strengthened and the soil nutrients and other noessential elements distributed uniformly in grasslands will gradually develop horizontal and vertical patterns in soil dimensions and finally lead to the formation of "islands of fertility", which makes the spatial heterogeneity of soil resource more evident. In addition, the enhancement of wind erosion with the encroachment of shrubs also increased the loss of soil resource, such as C, N, P, S and further influenced the redistribution of these elements among soil, atmosphere and biosphere. The shrubs encroachment and accompanied changes of biogeochemistry cycles will be markedly contributed to the global climate change through increasing the content of aerosol, carbon dioxide and nitrous oxide in the atmosphere and there exists a sensitive feedback mechanism between them. China has an area of grasslands of about 4 ×106 km2 or about 40% of the nation's total land surface and most of these areas have been affected by desertification, but reports on the biogeochemical effects of grass- shrub transition are limited. Therefore, Reinforcing research on shrub encroachment of grassland ecosystem along with the accompanied transformation of plant and soil resource distribution pattern is crucial for accurately understanding the desertification process and predicting the potential changes of elements biogeochemical cycle the in semi- arid and arid grasslands.
This paper explored land environmental issues in Three Gorges Resettlement Area, taking Wushan County as a case. Having summarized the major land environmental problems as well as their causes in the Wushan Resettlement, the paper set six river basins as its research units and chose eight representative factors of environmental risk from three aspects of ecosystem risk, social risk and environmental pollution risk. The paper made a risk evaluation of land environmental problems in the regions by employing Delphi method and Analytic hierarchical programming(AHP), and proposed a pattern of eco- friendly utilization in the regions for the sake of their sustainable development.
Abstract: Urban air pollution has become a major threat to human health now, and it seems that this situation will be worsening in the future. In particular, NOx pollution, which often causes many severe diseases, by urban transportation has been becoming a worse environment problem with the urbanization and has come to focus in both developing countries and developed ones. GIS- based study on urban air quality simulation and heath risk assessment come to a case in point in the world. This paper adopts GIS raster and surface analysis tools to build a spatial health risk assessment model on the basis of the present popular health- risk- assessment basic framework, which includes concentration, exposure, dose and effect. The model have made great advance in two ways of quantitatively assessing health effect and assessing air quality on urban local scale. The dose- effect function of pollutant toxicology is applied to quantitatively analyze the health effect, which succeeds in solving uncertainty problem confronting health effect assessment. In order to simulating pollutant exposure on the local urban scales, micro- environment study method is adopted to build exposure model including urban population distribution simulation and population time- activity pattern analysis. The study brings an effectively approach to assessing urban air quality. Finally, this paper simulates the NOx exposure distribution, classifies health risk and calculates risk population in a south- eastern coastal city of Fuzhou, China. The result shows that the study has practicability in assessing urban health risk of urban air quality.
Sahel is similar to agro~pastoral zone in Northern China in some aspects concerning environmental characteristics and environmental change, and there are some obvious linkages between them. The comparison analysis between them in precipitation, vegetation, drought events and dust storms can help better understand the variability of environment and climate in semiarid/arid regions in China and Sahel. Their interdecadal changes of precipitation have the similar trends. For Sahel, the interannual variability in precipitation is dominant before 1950s, while the interdecadal changes are outstanding from the mid of 1960s. A large portion of Sahel shows an increasing trend in NDVI. The interdecadal change of precipitation may be an important factor for the occurrence of drought, and temperature may also play roles in the formation of drought. The dust storm frequency has some evident relationship with precipitation on the interannual and interdecadal timescales, and the annual mean temperature and synoptic variability also have some influence on it. In agro- pastoral zone in Northern China, the interannual change is an outstanding characteristic in annual precipitation. In the north and east part of the zone vegetation experiences the increasing trend, and the south part shows a decreasing trend. The interdacadal change of precipitation played a role in the forming of drought events, but the same amount precipitation reduction may cause different drought in intensity. The spring dust storm frequency has tight relationship with previous winter temperature and synoptic variability, and also has some link with spring precipitation.
In arid areas, vegetation can reflect the status of environment directly as a sensitive element of environment; and the vegetation cover changes can represent evolvement and variance of the environment. So, the study of vegetation cover changes becomes an important instrument to open out the changes of environment and their laws in arid area. This paper is aimed at a special region of the lower reaches of Heihe River and the problems with its ecosystem of vegetation, discussing synthetically the vegetation cover changes and the elements related, such as the groundwater, the balance of soil water - salt, global climatic changes and human activities. The aim is to analyze the mechanism of vegetation cover changes exactly by analyzing correlative factors with vegetation cover changes extensively, and to provide supports for the study of environmental evolvement of the lower reaches of Heihe River. Finally, this paper summarizes existent questions in the study of vegetation cover changes, and puts forward relevant strategy to resolve them, providing references for the study of vegetation cover changes in the lower reaches of Heihe River.
Due to huge food need, arable land quality is very important in China, and how to evaluate its quality has been studied by many researchers. However, different regions of China are at different stages of development with different land use objectives. The first is yield maximization stage, and the household land use objective is to meet family food consumption need. The second is yield and profit optimization stage, and the house land use objective is to make more profits on the basis of meeting basic family needs. The third is profit maximization stage, and profit is the only land use objective for the household. Based on the theory of different development stages and land use objectives, a “Pressure- State - Effect - Reaction”model was developed in this paper to evaluate arable land quality at household level. The Pressure indictors include land scale, land quantity, society, economy and household family. The State indictors include land use type and pattern, input intensity and land use efficiency. The Effect indictors include soil quality, productivity and soil pollution. The Reaction indicators include governmental policies and economic measures. This model can be used to evaluate arable land qualities at different development stages, and the results can help the government make suitable policies to protect arable land for sustainable development.
It is of great importance to build an evaluation index system for the construction of resource- efficient society. With fully understanding connotation of resource- efficient society, in this paper, the concept and connotation of resource- efficient society was explained. An evaluation index system of resource- efficient society was built - the “543 index system”, including five kinds of resources, four processes of resource circle utilization, three layers and 70 indexes in total. An evaluation frame of quantifying single index and synthesizing multiple index is put forward. We explore the connotation of the resource- efficient society and build an evaluation index system, thus grading the resource- efficient society can be done.
Urban internal spatial structure in China is becoming more and more complex during the transition period when population, economic activities and social elements experienced a fast process of restructuring. Suburbanization of population accelerated in China in the 1990s compared with that in the 1980s. Great difference exists between the spatial restructuring of permanently registered population and that of external population. Generally speaking, the similarities of the spatial restructuring of population increased while the differences of it decrease. Analysis of the restructuring of urban industry and commerce shows that suburbanization and the centrifugal forces exert great influence on the evolution of urban internal spatial structure in the transition period. The factors of urban social space are closely related to the development of society. The types of social areas tend to vary and the components of each social area change from singleness to multiplicity. As a product of the planned economy, the model of urban internal spatial structure in the early 1980s exhibited more similarities than differences, with the feature of homogeneity, while that in the late 1990s was a product of market economy, exhibiting more differences than similarities, showing an obvious feature of heterogeneity and polycentric structure.
Since 1990's, the regionalization of economic growth becomes the general trend of global economic. Regional governance is the new topic of regional science studies, and it' s also the focal point of regional studies that democratization society is the background, since it emphasizes transverse management and public participation. Good building- up of regional governance system has a macroscopical effect of guide, guarantee and promotion. The misorder and turbulence of regional economy has been the problem which is made by the long- time ignorance of practice and the slow start of regional planning. General administrative economy has reduced working efficiency of market economy, therefore exploring new order of regional development becomes the hot point of regional development. Retrospection and conclusion for the relevant research of regional governance at home and abroad does favor to the enhancement of cognition to the concept, theory and practice of regional governance. After summing up the research history and identifying some concepts, the authors carried out synthetical commentary of these researches and analyzed prime issues of civil researches. The authors also pointed out the focus of difficulties and problems helming the direction of regional governance studies.
It is now widely recognized that new information and communication technologies (ICTs) have been changing the way in which firms do their businesses. As such, application of new ICTs will affect the development of industrial clusters, especially those of small and medium- size enterprises (SMEs). Electronic channels based on new ICTs are becoming a major platform of inter- firm relationships within clusters, which is critical to our understanding of cluster evolution and upgrading. In particular, new ICTs can enable small and medium- size enterprises to develop links across far distance and reduce both time and financial costs in establishing those links, and thus facilitate the internationalization of SMEs. This paper firstly reviews the development and major forms of ICTs application by enterprises in China, then discusses major factors affecting the application of new ICTs by SMEs in clusters based on field investigation of five clusters in Zhejaing and Guangdong provinces, and lastly, by using a case of shoes- making cluster in Wenling of Zhejiang province, analyzes the concrete affect of those factors. The majors discussed by this paper include industry- specific factors, enterprise factors, local social and cultural factors and regional information infrastructures.
Department of Urban and Regional Planning, Peking University, Beijing 100871, China) Abstr act: Industrial cluster is a very important economic phenomenon in China, but it bothers both the academe and the government to identify the industrial cluster, for there is no consistent and widely accepted criteria. Zhejiang province has a large number of manufacturing industrial cluster which cover various industrial categories. Using data from Census of Basic Units 2001, we apply the Location Quotient Method to identify industrial clusters. We consider that there is an industrial cluster in the district when the location quotient of a special industry comes up to 3 and the number of firms of the same industry comes up to 100 in a postal district. According to this standard, this article identifies 116 industrial clusters in four- digitindustry. The Location Quotient Method can tell us where the indusrtrial cluster is and which specific industry the cluster belongs to. In the following part, the spatial distribution and internal scale structure of the typical industrial clusters are analyzed.
