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    Earth Surface Processes
  • Earth Surface Processes
    CAI Yun-long
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    Land cover changes are not simple processes. There are complex simultaneous patterns of land-cover change, ranging from modifications in land cover to conversions and maintenance. There is a functional complexity within types of land-cover change, and a structural complexity between types of land-cover change, both in terms of spatial arrangements and temporal patterns of change. Land-cover change needs to be measured in its complexity to fully understand it. It is important to differentiate between land cover and land use when measuring patterns of changes. Land-use/land-cover change is a kind of extremely complex phenomenon. For all researchers involving in the study to avoid the unilateralism like blind-person touching elephant, they should search a new synthesis of studies. Therefore, the traditional approach of land use study is not effective and new topics are needed to be further found. A generalized and comprehensive understanding is required for the drivers of land-use change. We need a network of case studies that represents the spatial heterogeneity of the region and a multi-level approach that allows for a linkage between regional and local scale land-cover dynamics. Case study comparison is a major tool to derive generalizations of land-use/land-cover change research. We should develop new methods in mathematical modeling, descriptive models, empirical study, systematic case study and mechanism study. Linking house-hold-level information to remote sensing data is becoming a major tool to increase our understanding of land-use dynamics. The drivers of LUCC are always present but interact differently according to the temporal and spatial dynamics of the situation. A thorough understanding and modeling of these complex interactions is a prerequisite to generate realistic projections of land-cover change. The more important hypotheses for LUCC are those that frame the integration and synthesis of the science.

  • Earth Surface Processes
    XIANG Bao, LIU Ji-yuan, ZHANG Zeng-xiang
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    Based on methods of geographical information system and remote sensing technology, the single element's thematic digital terrain models of the elevation, aspect, slope, temperature, precipitation, maximum potential evapotranspiration, moistureand NDVI, which areintimately related to land cover environmental background in East Asia, are studied under unifiedprojection, unifiedspatial resolution and unifiedcoordination system, respectively. Then all the single elements are integrated to generate synthetic digital terrain models containing characteristics of each element by using Principle Component Analysis method. Finally, the characteristics of environmental background of land cover in East Asia reflected by the synthetic digital terrain model are analyzed. The characteristics of environmental background of land cover in East Asia are as follows: (1)The environmental background of land cover in East Asia has regularities of extention from northeast to southwest and gradation of southeast to northwest. At the same time, the distribution range of this characteristic is consistent with the range of monsoon climate area. We also found the zonal distribution of environmental background in western edge of this region is very complex. These phenomena completely incarnate the complexityof topography and climate in this area. (2)In the monsoon climate area, there exists not only the regularities of longitudinal zonality, characterized by extention from northeast to southwestand gradation from southeast to northwest, but also the regularitiesof latitudinal zonality featured by extention from east to west and gradationfrom north to south. (3)In northwest inland area including Xinjiang, northwestern part of Qinghai-xizang Plateau, western part of Inner Mongolia and southwestern part of Mongolia, a broad sense of eastern part of central Asia dominated by mountainsand basins in topography, the southeast monsoon, temperate westerly and Arctic Ocean air currents are inaccessible to reach this area, so the quality of environmental background of land cover in this area is very low. (4)In northern part of East Asia, because of flat terrain endowed with certain amount of precipitation compared with northwest inland area,the land cover environmental background condition is relatively high and has the longitudinal zonality of extention from east to west and gradationfrom south to north.

  • Earth Surface Processes
    LONG Hua-lou, LI Xiu-bin
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    Land use and cover change (LUCC) is an important component of global environmental change research, and terrestrial transect initiated by the international geosphere-biosphere programme (IGBP) is a suit of integrated global environmental change research, which emphasizes interpretation of global environmental change problems with grads methods. Taking transect as a series of coherent research sites, LUCC can determine how land use and corresponding land cover change under the influences of social and environmental factors. Transect of the Yangtse River (TYR), with obvious grads either in the change of physical environmental factors or in the level of socioeconomic development, was taken as a study area in this paper. Land use changes in several years or decades are mainly driven by socioeconomic factors and restricted by physical factors, and they can be mainly reflected by the changes of cultivated land and built-up land, which are tightly interrelated with human productive activities. Land use changes of TYR in future 30 years were modelled through applying revised Generalized Thunen-Ricardian model. It shows that, between 2000 and 2030, the area of cultivated land in eastern part will further decrease; however, the area of cultivated land and urban and rural settlements in overall will increase. According to the spatio-temporal characteristic of land use changes in future, corresponding countermeasures were put forward as the following to realize regional sustainable sustainable land use: (a) scientifically laying out city/town planning and strengthening reconstruction of old city zone; (b) strictly managing rural housing and carrying out aggregating scattered houses; (c) coordinating the relationship between land development and cultivated land protection; and (d) realizing regional sustainable socioeconomic development relying on resources and breaking the cycle of poverty and unsustainable land use.

  • Earth Surface Processes
    ZHU Hui-yi, HE Shu-jin, ZHANG Ming
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    According to remote sensing data, 30% of the total land area in terms of use patterns had changed in Bohai Rim during 1985-1995.Cultivated land change was the most important type, which was mainly transformed to rural dwelling land, forest, grassland, urban land, orchard and water area. Based on the analysis of cultivated land transformation and its relation between population and agroeconomic development, this article clarifies that land management policy, increase of per capita living space, adjustment of agricultural production structure and urbanization are the major driving forces of land use change in the region. Among the driving forces, the land management policy, especially the policy for cultivated land preservation was the most important factor that affected the regional land use change which facilitated the transformation of other land-use types into cultivated land through balancing those occupied. Population growth did not necessarily bring the increase of cultivated land. The even lesser cultivated land through improving crop yield could still satisfy the increasing demand for food. Population growth, variation of population density had no crucial affection on land use change but the increase of per capita living space could exert greater impact on regional land use change. Agroeconomic development incurred the adjustment of production structure and made cultivated land be transformed to orchard, water area and forest/grass land with the consideration of ecological environment. Urbanization drove land use change in aspects of both cultivated land quality and level of labourers.

  • Earth Surface Processes
    HE Chun-yang, SHI Pei-jun, CHEN Jin, ZHOU Yu-yu
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    In the paper, based on the LandsatTM/MSS data in 1975, 1984, 1991 and 1997, the land use/cover change in Beijing area was examined with the support of RS and GIS. Conclusions of the study are drawn as follows: The large-scale land use/cover change took place in Beijing area in the process of rapid urbanization from 1975 to 1997 with major characteristics of urban expansion at the expanse of encroaching cultivated lnad in the plain area and of obvious structural readjustment occurring in other land use/cover types. There existed obvious regional difference in land use/cover change in Beijing area during the past twenty-odd years and the land use/cover change rate in exurb has already exceeded that in suburb in the 1990s. With drastic land use/cover change in the region, the barycenterof the high-density urban land moved to the northwest to certain extent during the past decades, showing that the urban land use density in the west and northwest of Beijing city improved obviously with the expanding trend to the west and northwest in the same period.

  • Earth Surface Processes
    LU Qi, ZHAN Jin-yan, REN Guo-zhu
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    Beijing is one of the ancient cities in China. In history, land use and land cover in its territory changed with intensities of human activities. The most striking land use change is the expansion of urbanized areas no matter fast or slow in different periods. Its historical development process could be roughly divided into two periods in this paper, one is from Liao Dynasty when Beijing initiatively became the capital to 1911 when traditional China ended. Another period is from 1911 to the present, particularly from 1949 to 1997 on which the discussion on land use and cover change is focused. The period of 1949 to 1997 could be divided into two sub-periods, i e , planned economy period from 1949 to 1978, and the institutional and market oriented transition period from 1978 to the present. Through the brief discussion, we can see that land use/land cover change has been accelerated in the past 100 years, especially in the past 50 years because of the changes of social ideologies, policies, population growth, technological improvements and the strengthening of economic power. More detailed and quantitative studies of the relationship between those social-human factors and the urbanization as well the land use/land cover change need further studies in the future. The consequences of land use and cover change in Beijing, the future development trends of the city and some related issues are also discussed in the paper.

  • Earth Surface Processes
    FU Su-hua, DUAN Shu-huai, LIU Bao-yuan
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    Varying soil loss resulting from different land use leads to problems of soil coarsening to different degrees in Beijing hilly area. In this paper, the data of conventional tillage plot, the fallow plot and the wasteland plot at Miyun county, Beijing were used. The topsoil samples and profile samples were taken from the upper, middle and down slopes of the plots. The soil samples were sieved. Then the rock fragment samples, whose diameter is over 2 mmeach, were weighted by means of sieving. The percentage of rock fragments in the samples was calculated. The results show that thepercentageof rock fragments in fallow plot is the highest and the percentageof rock fragments in wasteland is the smallest. Provided the percentage of rock fragments in the samples of wasteland was known at a normal value, and the soil textureindex was expressed with the ratio of the percentageofrock fragments for other land use to the one in wasteland, then the indexes of fallow land, conventional tillage plot and wasteland are 2.96, 2.07 and 1, respectively. The characteristic of soil coarsening in section varies with different land use purposes.The section at wasteland is free from soil coarsening, while the sections at fallow plot and conventional tillage plot experience apparent soil coarsening. The results can be applied for land use planing and soil degradation evaluation.

  • Earth Surface Processes
    LIN Mei-zhen, ZHANG Yi-li
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    The driving forces and the changes of the tropical forest in Hainan Island of China were studied mainly by means of analyzing investigation data and forest survey materials, interpreting remote sensing data, using contour maps, and overlaying them with GIS, investigating the spatial variation survey and visitation during April of 1998 and May of 1999. The dynamic changes of tropical forest change as follows: 1) The area of tropical forest in Hainan Island changed obviously, which decreased from 1 200 000 hm2 (1950) to 415 200 hm2 (1979), and restored to 614 700 hm2 by 1998.2) Since historical times, the changes can be divided into deceasing period (-1987) and increasing period (1987-). The former can be subdivided into three phases: resource decreased slowly (from Han Dynasty to 1933, annual average decrease of 984 hm2), resource decreased sharply (1933~1979, annual average decrease of 27 800 hm2) and resourcedecreased slowly (1979-1987); from1978 to 1998, the resource was restored steadily, annual average increase 20 300 hm2. 3) Thespatial changes are mainly represented in the processof deforestation taking place from coastal plain and mesa to inland hill and basin, and finally to mountainous areain the middle of theisland. 4) Themain factors which affect the tropical forest are not the same in different phases. FromHan Dynasty to 1933,it is just due to aboriginal cultivation; from 1933to 1950, it is due to plundering cutting and destroying; and in the last 50 years, the ultimate causeis due to over fastincreasing of population and changes in policy and economy system.

  • Earth Surface Processes
    CHEN Li-ding, FU Bo-jie, Ingmar Messing
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    With population growth and arable land decrease, the pressure of human activity on land resource is becoming greater. How to realize sustainable land use has become the focus of global society. Both the time scale and spatial scale have to be concerned when a sustainable land use planning was made. Normally, ecological suitability, economic feasibility and social acceptance of land use scenario have to be considered. Currently, most works concern more on theoretical aspect of sustainable land use rather than some practical approaches to realize sustainable land use. In this study, a procedure for carrying out such a planning is presented, based on results from a research project in a small catchment on the Loess Plateau. A land suitability evaluation for rainfed agriculture based on biophysical parameters, and a comparison between land suitability and current land use, were first carried out. Some potential land use scenarios, based on surveys on biophysical and socio-economic parameters in the catchment, and plans by the authorities, were proposed for further evaluation of their effects on soil erosion, economic feasibility and social acceptance. The results indicated that the following land use scenario was acceptable: all land with deep soil and slopes smaller than 15° is used for agriculture cropland, possibly combined with biological conservation measures, such as mulching combined with improved fallow, and all land with slopes steeper than 15° is used for other purposes (orchards and other cash trees, woodland, shrubland, grassland). A great reduction of on-farm income, however, would be induced on the short term by such a scenario. Local farmers will find it difficult to accept unless financial support from external sources is available. On the long term, the scenarios will be promising for both economic income improvement and soil erosion control since some production will be obtained from the conversion of cropland into orchards/cash trees (preferably on slopes 15~25°). Thus the land-use modification should be carried out gradually. On the short term (5 year), it is suggested that cropland on slopes steeper than 25° is returned to woodland/shrubland/grassland while also fruit trees are planted on slopes of 15~25°. Within 10 years, cropland with slopes steeper than 15° is suggested to be converted into orchard/woodland/shrubland/grassland.

  • Earth Surface Processes
    ZHAO Jian, WEI Cheng-jie, HUANG Li-fang, YAN Shou-yong
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    Based on time series mapping of land use in Hainan Island, the dynamic changes of the land use in the island have been monitored using remote sensing and GIS. The methods used in this paper include: land use transition matrixes, land use dynamic mapping, mathematical models and image interpretation. All these methods are used separately to explore the characters and laws of land use changes in Hainan from different aspects. In fact, transition matrixes are good for describing the general trends of land use changes and conversion amount among different land use types. Land use dynamic mapping is often used to discover the changes of land use in time and space. Mathematical models are utilized to calculate the extent and speed of change, including increase and decrease of land area for different purposes. The method of image interpretation is easy to monitor the land use changes,such as mangroves,shelter-belt and sandy land in the coastal zone directly and visually. Therefore, the results of the study in Hainan show that integration of multiple techniques and multiple methods could help people gain a deep understanding about land use dynamics and the driving forces of these changes.

  • Earth Surface Processes
    WANG Xiu-hong, HE Shu-jin, ZHANG Yi-li 1| LUO Ming
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    Integrated evaluation on land use degree for each county in western China was made by using factor analysis. Based on the integrated score of each evaluated unit (county or county-level city), which reflected the structure of land use, and taken the eco-geographical system of China as a controlling framework, evaluated units were united with the GIS technique; thus, the combined division method of From-top-to-bottom (TB) and From-bottom-to-top (BT) was tested. Western China, which included 12 provinces, autonomous regions and municipality, were divided into three large regions of East monsoon region, Northwest arid region and Tibetan alpine region and further divided into 30 subregions. The various types of indices commonlyused to illuminateland use degreejust reflect the situation of land usefrom a few on the sides. Therefore, the simply using of these indicesto proceed mathematical analyses and to dodivision research would usually deviate from the right direction. Taken the eco-geographical system of China as a controlling framework, the combined division method of TB and BT can be used with hierarchical structure and suggestivedirection. Using the factor analysis, information provided by many indices can be purified and synthesized. The result of data deduction also keeps the structure of samples in high dimension, especiallythe structure related to ordering. Thus, the comparisonand union of the evaluated units have one directly referenced index rather than lots of indices. The application of GIS technique makes the orderingof integrated score closely related to the space attributes among samples, and avoid the irrational union of evaluated units which have almost the same integrated score but have very different land use structure. Also the GIS technique makes the division methods combined between that of TB and that of BT. Many attributes of the divided regions are gradually changing;therefore, the result of division is opposite. County boundary must be consideredfor maneuverability; however, some countieshave large areas, resulting in rather differentecogeographic conditions. With more detailed inquisition information about land use and perfecting study method, the division result would be more reasonable.

  • Earth Surface Processes
    QIU Yang, FU Bo-jie, WANG Jun, CHEN Li-ding
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    The multiple-linear regression models with more readily observed environmental variables (land use and topography) were developed to spatially predict soil moisture content using six methods and their performances and cost-benefit were evaluated using 13 indices in Danangou catchment (3.5 km2) in the loess area of China. Soil moisture measurements were performed biweekly at five depths in soil profile (0~5 cm, 10~15 cm, 20~25 cm, 40~45 cm and 70~75 cm) on 81 plots from May to September 1999 using time domain reflectometry (TDR). It is indicated that the 13 measured indices almost exhibit the similar conclusions. In terms of fitness, optimum, precision, outlier and cost-benefit, the with-attributes group models, including generalized multiple-linear regression models with environmental attributes (GMLRMs) and stepwise multiple-linear regression models with environmental variables (SMLRMs), were shown to be superior to those multiple-linear regressions models with linear transformation on environmental attributes by principal component analysis (PCA-based group models) and those regression models with nonlinear transformation by detrended correspondence analysis (DCA-based group models). Within each group models, the models using generalized-method or enter-method are better than those using stepwise-method are. However, such within-group differences are not so evident as that of inter-group. Among the six methods, the GMLRMs are the best in terms of fitness, optimum, precision and outlier based on the 11 performance indices, while the SMLRMs are most effective and economical according to the Akaike information criterion (AIC) and Schwarz or Bayesian information criterion (SIC) that can evaluate the cost-benefit of models.

  • Earth Surface Processes
    LIU Xiang-nan, XU Hong-mei
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    Heterogeneity in land use is shaped as a result of complex interactions between climate, terrain, soil, water availability, and various human activities. Different land use spatial patterns have different geographic causative mechanisms, and the ecological functions and their spatial graphics also vary. The key problem of this study is the quantiative representation of different land use patches, and description of actual patches with graphics. In this article, landscape ecology and geographical graphic information theory are used to discuss this problem by taking Qianguo county of Jilin province in Northeast China as a case. Based on studies of numerous land use patches, we discuss the quantitative description and graphic presentation method of patch shapes of various principal land use types,obtain characteristic graphics of different land use ty pes and law of spatial distribution.The results indicate that the interior rate of residential patch is the lowest, which decreases with the increase of patch area at the scale of 0 1km2, while grassland is the highest which increases with the increase of area. The form index of residential patch and grassland changes slightly with patch area, and forest increases with patch area.The fractal dimension of grassland is high and increases with the patch area, while residential patch patch changes a little. The circularity of residential patch remains unchanged with the patch area changes. The patch shape of forest is mostly similar to rectangleas the patch area is less than 0.1 km2. The grassland patches shape as rectangle with curvatures at the edges.The patch shape of water area is similar to ellipse. The shapes of residential patch and farmland are simple, and farmland presents as echelon composed by several rectangles when the area is larger than 1km2. These two land-use types are reflected intensively by human activities and the patch shapes often have right angles. The other patch shapes are irregular graphics with curvatures at the edges. The result of VCM analysis shows patches of forest are scatteredly distributed with patch distance mostly exceeding 2000 m. The patch distance of grassland is small, mostly less than 1000 m as patches are mostly distributed in concentration. Almost all residential patches are distributed regularly with patch intervals of 3000 m. This study provides basis for further analysis of the geographic causative mechanism and ecological function of different land use spatial patterns.

  • Earth Surface Processes
    ZHANG Ming, ZHU Hui-yi, HE Shu-jin
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    Land-use and land-cover change (LUCC) has become a key field for the research of global environmental change since the 1990s. More attention is paid to the identification and description of the driving forces of LUCC. For all kinds of limitations, it is difficult to incorporate different influencing factors into a whole model to carry out such an analysis. Canonical Correlation Analysis (CCA) is a kind of traditional statistical model to show the relationship between two multiple stochastic variables. It is widely applied in different research fields to describe the relationship between the set of criterion measures and the set of explanatory factors. This paper introduces the connotations, characteristics and procedures of this multivariate analysis. It is combined with one of the analyses on geographic problems, to identify the relationship between the land-use patterns and its influencing factors. Taking the Bohai Rim in China as an example, through the preparation of the data, operation procedures and statistical checks, the application of CCA in a practical study is given comprehensively. It is shown that CCA could be widely applicable to the geographic analysis, especially to the identification of the relationship between land-use structure and its influencing factors. Through the canonical loadings analysis, the influencing extension of different factors to the dependant variables or the contribution extension of explanatory variables to the explained variables could be described quantitatively. As CCA is carried out in combination with a series of data checks and precision tests, it makes the specific analysis more rational and scientific.