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    15 November 2001, Volume 56 Issue 6 Previous Issue    Next Issue
    Analysis on Spatial-Temporal Features of Land Use in China
    WANG Si-yuan, LIU Ji-yuan, ZHANG Zeng-xiang, ZHOU Quan-bin, ZHAO Xiao-li
    2001, 56 (6):  631-639.  doi: 10.11821/xb200106001
    Abstract ( 1074 )   PDF (1134KB) ( 2503 )   Save
    The research on land use and land cover change is a core for studies on the global changes. Also the research of spatial-temporal features of land use/land cover change is significantly important for better understanding land use/land cover change and environmental management for sustainable development. In order to study the spatial-temporal changes of land use and land cover, the technologies of remote sensing and geographical information system were used to analyze the spatial dynamical features and temporal dynamical features of land use in China. The mathematical methodology for study on land use change was explored and developed. This research focuses on the dynamical analysis of spatial-temporal features of land use and land cover change of China in recent five years, such as land use types, land use degree, plantation status, city expansion, and so on. The results are: the cultivated land, water area, built-up or non-arable land area are increasing and forestland and grassland keep decreasing in the five years. The change of land cover types is not obvious in the corresponding period. The area-change of cultivated land has taken place mostly in the middle and eastern China. However, the area-change of forestland and grassland and unused land has mainly taken place in the Xinjiang Uygur Autonomous Region, the Inner-Mongolia Autonomous Region and Heilongjiang Province in China.
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    A Study on Land Use and Land Cover Quality Change:Taking Yellow River Delta as a Case
    XU Xue-gong, CHEN Xiao-ling, GUO Hong-hai, LIN Hui-ping
    2001, 56 (6):  640-648.  doi: 10.11821/xb200106002
    Abstract ( 450 )   PDF (732KB) ( 667 )   Save

    Land use and land cover change (LUCC) plays, an important part in the studies of global environmental change and sustainable development. Land quality change can particularly reflect the impacts of human socio-economic activities on environment. By means of land classification for LUCC to different times of remote sensing information, picking-up vegetation index (NDVI), and assaying field repeated soil samples, as well as statistical analysis, this paper studies land use and land cover quality change of past several to 21 years in the Yellow River Delta. The conclusions are as follows: 1. In the Yellow River Delta, although sediment loads carried by the Yellow River result in rapid expansion of land area, the main driving force of LUCC is derived from human economic activities. 2. In the macroscopic view, land use and land cover quality change shows a tendency to improve because of water conservancy projects, vegetation cover and increase of per unit area yield of crop so that the overall ecological environment is improving in the mass. But in the microcosmic and point analysis, there are different and imbalanced development within the region. The task of transforming saline land is still arduous. The hidden trouble of soil fertility depression can not be neglected. 3. Both natural force and human action can engender environmental positive and negative effects. But it is more difficult to restore the latter made by human activities. The paper brings forward measures for sustainable land use. Finally, there is a discussion about issues of further study.

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    Environmental Emigration Stress of Slope Farmland in the Three Gorges Area
    WANG Li-ming, YANG Yan-feng, Guan Qing-feng
    2001, 56 (6):  649-656.  doi: 10.11821/xb200106003
    Abstract ( 400 )   PDF (878KB) ( 501 )   Save
    As a fundamental measure of eco-environmental restoration, the process of returning slope farmland to woodland and grassland is being conducted in the reservoir area of Three Gorges Dam gradually. However, de-farming of slope farmland will reduce the amount of farmland in the de-farming area, this is especially true in areas with concentrated slope farmland. The people who de-farm their farmland can obtain enough farmland again in two main ways: some of them can gain enough farmland by adjustment of farmland with those in the same village, the others can not gain enough in local area and have to emigrate to other places. The latter can be called environment emigrants or ecology emigrants. In the research, we set up a de-farming stress index model and an environmental emigration model using GIS based on GRID data structure, and simulate the latent amount of environmental emigration caused by dc-farming of slope farmland in the reservoir area. The simulation indicates that the latent emigration amount caused by de-farming is quite large. When the de-farming stress index reaches 40%, the amount is as large as 890 000, which is equivalent to the allocated amount of the emigtants around the reservoir caused by the submergence of the Three Gorges reservoir area. So it should be considered as a big problem in the eco-environmental resteration in this area. To resolve the emigration stress, some suggestions are put up in this research: Firstly, the emigration plan should be included in the de-farming plan. For the successes of the experience, some financial support policies are attempted. But the effects are limited. As the dc-farming experiences are conducted in wider regions, the financial support will become a heavy burden. So emigration is the fundamental countermeasures to reduce population stress in slope farmland. Secondly, besides the Three Gorges reservoir area, other provinces especially those located in the lower reaches of Yangtze river should adapt part of the environment emigration . Those provinces such as Hubei, Hunan, Jiangxi benefit from the ecological effects of the de-farming project.
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    Land Use Change and Its Regulation of Yangou Watershed in Loess Hilly-gully Region
    XU Yong, Roy C. Sidle
    2001, 56 (6):  657-666.  doi: 10.11821/xb200106004
    Abstract ( 526 )   PDF (884KB) ( 596 )   Save
    Based on the topographic map in 1966, remote sensing image in 1988 and land use survey in 2000, three land use maps were made in Yangou watershed. And assisted by spatial analysis techniques of GJS, the spatial and temporal differentiation of land use change was analyzed in that watershed. As a result, this paper found: (1)Land use change of Yangou watershed could be divided into three phases from 1949 to 2000. The main character of prophase (1949-1988) was that slope land was expansively cultivated and natural forestland was continuously destroyed. The land use structure of the watershed was steady comparatively in 1989 to 1996. The key period of regulating land use structure of the watershed was in 1997 to 2000. Land use structure during the period showed sharp changes along with the reduction of vast farmland, a speedy increase in orchard and got-up grassland and a increase in open woodland. (2)During 1997 to 2000, the important measures of regulating land use structure of the watershed included formulating the operating rules, drafting the practicable plan, regulating the land use structure based on the topographic slopes, selecting and fostering rural industries and playing the rational roles of administrators, researchers and farmers. (3)The benefit analysis of soil & water conservation and rural economic development based on the land use scenario in 2000 indicated that the percentage of reduction sediment was 80%, that of permanent vegetation cover was 78.48%, per capita GDP was 1541 yuan(RMB) in 2000 and 4311 yuan in 2010. Its rural economic development was verified to be sustainable by predicting the changes of per capita basic farmland, orchard area and sheep in 2040.
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    Relationship Between the Fractional Vegetation Cover Change and Rainfall in the Yellow River Basin
    SUN Rui, LIU Chang-ming, ZHU Qi-jiang
    2001, 56 (6):  667-672.  doi: 10.11821/xb200106005
    Abstract ( 788 )   PDF (486KB) ( 1024 )   Save

    Vegetation plays an important role in the energy, matter and momentum exchange between land surface and atmosphere and the change of vegetation is mainly caused by climate variation and human activities. Therefore, it is necessary to study the relationship between climate factors and inter-annual change of vegetation, which will help us to understand global change. In order to understand the effects of rainfall on vegetation cover, we selected the Yellow River Basin in China as the study area to assess the inter-annual change of fractional vegetation cover in the Yellow River Basin, and analyzed the relationship between rainfall and fractional vegetation cover using 8 km resolution multi-temporal NOAA AVHRR-NDVI data from 1982 to1999. The data are from NASA Pathfinder AVHRR Land data sets. The spatial distribution and dynamic change of fractional vegetation cover were studied by using yearly maximum NDVI. The results show that in spite of inter-annual fluctuations, there exists an inclining trend of fractional vegetation cover for the whole basin, which is different from the trend of annual rainfall. The inclining trend may be caused by human activities while inter-annual fluctuation may be caused by climate factors. Finally, the correlation coefficients between NDVI and rainfall in different periods (annual rainfall, rainfall in flood and non-flood seasons) were computed for every pixel to assess the effect of rainfall on fractional vegetation cover change. The results show that there is good relationship between NDVI and rainfall in the Yellow River Basin, especially in arid and semi-arid steppe zones, and inter-annual change of fractional vegetation cover is mainly affected by flood season rainfall. However, human activities can reduce the effect, for example, the effect of rainfall on NDVI is small in irrigated cropland.

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    Fluctuation of Soil Erodibility Due to Rainfall Intensity
    ZHANG Ke-li, CAI Yong-ming, LIU Bao-yuan, PENG Wen-ying
    2001, 56 (6):  673-681.  doi: 10.11821/xb200106006
    Abstract ( 651 )   PDF (564KB) ( 913 )   Save
    On the base of evaluation of previous researches about soil erodibility, the advantages and disadvantages of present representative indexes of soil susceptibility to erosion were discussed in this paper, and principle of choosing index of soil for soil loss prediction was suggested. The erodibility values of phaeozem, loess in China and andisol in Japan were calculated using the data from fieldobservations. The variance in erodibility through seasons and the relation of soil erodibility to rain intensity was also analyzed. Results show that the rate of soil loss per rainfall erosivity index used in USLF may be the best index to represent the effect of soil properties on soil erosion. However, the present erodibility factor in use can not be applied directly in predicting soil loss caused by a specific rainstorm. The values of soil erodibility vary obviously through seasons and have different pattern from one place to another. But the field runoff plot data of which the maximum 30-minute rainfall intensity is larger than 25-30mm/hr are used to calculate the soil erodibility, the values appear relatively stable and approaches to annually average erodibility value.
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    Change of Temperature in Tibetan Plateau From 1961 to 2000
    DU Jun
    2001, 56 (6):  682-690.  doi: 10.11821/xb200106007
    Abstract ( 999 )   PDF (772KB) ( 893 )   Save

    Using the data of monthly mean temperature, maximum and minimum temperature from 1961 to 2000 in Tibet, the linear trends of the annual and seasonal temperature are analyzed. The results show that, the mean temperature displayed warming trend in most parts of Tibet, especially in autumn and winter. The asymmetry was detectable in Tibet, the type of asymmetry was mainly the increase of Tmax and Tmin, while Tmin increase was bigger than that of Tmax. The increase of Tmax occurred mainly in summer and Tmin in winter. The decrease of daily temperature range (DTR) was in all seasons (except summer). Warming was displayed at all latitudes, the increase was the strongest in spring and autumn, secondly in winter, the trend was stronger on the higher altitude than on the lower altitude. In addition, the linear trend of the warming for annual mean temperature over Tibet during the past forty years indicated an increase of 0.26 oC / 10 a, it is obviously higher than in other parts of China and in the whole globe. There were more anomalous cold years in the 1960s, whereas anomalous warm years in the 1990s.

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    Classification and Identification of Severity Degree of the No-flow Events in the Yellow River
    QIAN Zhenghan, NI Jinren,, XUE An
    2001, 56 (6):  691-699.  doi: 10.11821/xb200106008
    Abstract ( 502 )   PDF (924KB) ( 546 )   Save
    Based on a review of the characteristic factors used for no-flow behavior analysis in previous studies, this paper proposed an additional comprehensive index which could remedy some deficiencies of other factors and thereby constitute a basis for classification of the severity degree of the Yellow River no-flow events. According to the cluster analysis of the measured data since 1972 when the no-flow phenomena occurred in the Yellow River first time, five severity levels could be classified for no-flow events in the Yellow River. Furthermore, the severity level is closely related to the incoming runoff as well as its fluctuation within a year expressed in terms of a deviation coefficient. A BP-typed ANN model was developed for identifying the complex response of the severity level to flow characteristics such as the incoming runoff and its fluctuation. The proposed method is of significance to the quantitative assessment of the severity level of the no-flow events in the Yellow River, and its applicability was proved through the comparison between the predicted and the measured results.
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    The Relationship Between Vegetation Cover and Sand Transport Flux at Mu Us Sandland
    HUANG Fu-Xiang, NIU Hai-Shan, WANG Ming-Xing, WANG Yue-si, DING Guo-dong
    2001, 56 (6):  700-710.  doi: 10.11821/xb200106009
    Abstract ( 720 )   PDF (703KB) ( 964 )   Save

    Wind erosion has played the major role in shaping Mu Us landscape. Although Mu Us Sand land is a hot spot, of research, the detail of wind erosion in Mu Us has been poorly understood. On the basis of observations in Mu Us Desert, we determine the threshold of wind velocity and present sand transport equations on bare and vegetated land. Furthermore, we discuss the quantitative relationship between vegetation cover and sand transport. We get a quite good understanding of the effect of vegetation on wind erosion.

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    The Consideration of Strategic Innovation of West Development Based on Theories of Economic Geography
    FAN Jie, CAO Zhong-xiang, ZHANG Wen-zhong, XU Yu-dong
    2001, 56 (6):  711-721.  doi: 10.11821/xb200106010
    Abstract ( 481 )   PDF (995KB) ( 698 )   Save
    In China, regional development is always the main field of economic geography. Especially since reform and opening up, economic geography has developed substantially with the positional elevation of regional development in national economy. At present, the western development strategy will have a deep effect on the pattern of Chinese regional development in the 21st century while economic geography has stepped into the period of transferring from traditional to modem economic geography. Therefore, to consider the innovative strategy of western development from the viewpoint of theories of economic geography is quite necessary to either the cognition of western regions or the development of economic geography. The theories of economic geography have had a significant effect on regional development in China, including the spatial organization theory, the industrial development theory and the instructive theory. As the theoretical bases of the three economic zones construction, "T-shaped" mode of territorial development strategy, areal division and cooperation and so on, the spatial organization theories, including economic locational theory, spatial structure theory, economic regionalization and territorial production complex theory, played an important role in regional development distribution of China. Industrial development theory introduced from economics opens out the rule of regional industrial development, of which the theories of industrial structure elevation and regional trade are of directive significance to the adjustment of industrial structure and exertion of regional comparative advantage. The theory of PRED system harmonious development and the thought of sustainable development brought the complete transformation of regional analysis conception. For the gap of regional development level due to the difference of industrial structure, regional division of industry frequently leads to the economic interest expanse from undeveloped to developed region. It turned out that the western construction didnt promote the improvement of peoples standard of living synchronously with the regional development and cannot overcome the contradiction between economic development and environmental protection. And also, the application of economic theories above-mentioned encounters different obstacles. The paper lays stress on the enforcement of sustainable development strategy in western development, to which there are three premises: calculation of environmental protection and income of western regions from it. materialization of resource product value and reasonable economic benefit of human resource protection. The objective of western development should take inhabitant enrichment for the core. improvement of local people’s income level for the keystone, narrowing of social development gap between the west and the east for the instructive thought of gradient devotion of the government, and also strengthen environmental construction and human resources development to build up the sustainable development capacity of western regions. To construct regional characteristic economy and implement unbalanced development strategy arc feasible ways to the adjustment of industrial structure and regional economic development. Characteristic economy mainly includes characteristic agriculture (herding, fruits and so on), light industry (medicine and foodstuff). tertiary industry (tourism industry) as well as high-tech industry. A reasonable spatial structure should be based on the development mode of point-axis system.
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    Local Clustering: a Case Study on PC-related Manufacturing in Dongguan
    TONG Xin, WANG Ji-ci
    2001, 56 (6):  722-729.  doi: 10.11821/xb200106011
    Abstract ( 595 )   PDF (378KB) ( 806 )   Save

    Through a case study on PC-related manufacturing in Dongguan, this paper examines the transformation of global-local ties in the development of local clusters in the context of Pearl River Delta, a foreign investment driven industrialized area in China. Following a brief theoretical review on the industrial cluster and the dynamics of global PC market environment, the changing structure of local PC production network is analyzed. The development of the local PC production network is divided into two stages: first, from the late 1980s to the early 1990s, export oriented manufacturing plants with strong global linkages but weak local linkages were established under the export processing regulations; second, from the middle 1990s till now, the local electronics intermediates production network kept growing with the Taiwan PC makers flood-in. The changing structure of local industrial linkages is intervened with the dynamics of social relations between different agents, which leads to the challenges of institutional innovation in the development of local clusters. Then, we analyze the congestion of custom, a prevalent problem faced by most local PC makers at present, and the ongoing bargain on regulations between overseas investors and local policy-makers. We argue that this institutional bottleneck of local production network is among the results of the structural changing, and cannot be solved only by readjustment at operational level. The forthcoming entrance WTO is a step towards improvement. However, the establishment of local common sense on new market rules among investors, local officials and labors is still a long way to go.

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    The Category Classification and Coding Systems of Urban Public-Geographical Information
    WANG Ying-jie, CHEN Tian, YU Zhuo-yuan, CHENG Xi-fang
    2001, 56 (6):  730-739.  doi: 10.11821/xb200106012
    Abstract ( 621 )   PDF (480KB) ( 1046 )   Save
    This paper discussed some key matters of urban public-geographical information standardization. It mainly analyzed the object and scope of urban public-geographical information that represents the characteristics of multi types, complex, connectivity and dynamics. Based on that, the rules for classification and code representation are constructed. According to such regulations to form category index system, and code sheet as well as coding system, which will provides a base for the fully using of intelligent management methodologies, to collect, deal, query, index, analyze, manage and share the urban public-geographical information.
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