Table of Content

    25 May 2007, Volume 26 Issue 3 Previous Issue    Next Issue
    Geo-information Science
    Modeling man-land tensity of Chinabased on 1km grid data
    WANG Li-ming, ZHANG Shao-hui, ZHANG Da-quan
    2007, 26 (3):  425-434.  doi: 10.11821/yj2007030001
    Abstract ( 1941 )   PDF (611KB) ( 1357 )   Save
    Man-land tensity, a value that quantitatively indicates the tension between human activity and physical environment, can be calculated by function with human pressure on the physical environment and environment carrying capacity to the human activity. A man-land tensity model is put forward in this paper through three steps. Firstly, the Environment Carrying Capacity Model (EC) is built by using the idea of Land Carrying Capacity Model and Ecological Footprint Model for reference. EC comes from the physical capacity normalized by Equivalence Factor and Yield Factor, and modified by human factors of city distribution and transport network density. Secondly, integrating production and consumption, the Human Activity Pressure Model (MP) is set up with 1 km population and GDP data. Thirdly, the Man-Land Tensity Model (MLT) is constructed based on EC and MP at 1km grid data platform. Compared with the previous research based on administrative region, 1km grid is smaller on grain size and it can present the more detailed areal differentiation. The result shows that, the high-value of man-land tensity has a spot-shaped or belt-shaped distribution at cities or their suburbs or along the main economic axes, where the human activity is intense.The highest value area appears in the Pearl River Delta, the Yangtze River Delta and the Beijing-Tianjin-Hebei Metropolitan Region.The middle-value zones are distributed in North China Plain, the Two-Lake Plain (in Central China), Sichuan Basin,etc. The ecological environment is fragile in West China, where the human activity exists mainly in cities and the farming-pastoral zones, and here are distributed the high-value zones of man-land tensity.
    References | Related Articles | Metrics
    Earth Surface Processes
    Scale issues in digital terrain analysis and terrain modeling
    LIU Xue-jun, LU Hua-xing, REN Zheng, REN Zhi-feng
    2007, 26 (3):  433-442.  doi: 10.11821/yj2007030002
    Abstract ( 2045 )   PDF (1769KB) ( 2046 )   Save
    Digital elevation model (DEM) and terrain analysis based on DEM is scale-dependant. With the view of geoscience analysis and modeling, the paper mainly discusses scale and scale effect of terrain analysis based on grid DEM. Firstly, the paper outlines five common uses of the term "scale" within DEM and terrain analysis which are geographical scale, sampling scale, DEM structure scale, analysis scale and cartographic scale. The geographical scale means the spatial extent of the DEM or the area of coverage; the sampling scale refers to sampling intervals in DEM data collection; the DEM structure scale refers to the resolution of DEM which includes DEM horizontal resolution and vertical resolution; the analysis scale refers to the analysis extent of local windows including window size and threshold value; and the cartographic scale which is used for map reflects the ration between the measurements on a map and the actual measurement on the ground. Secondly, the paper's focus is put on the scale effect of terrain analysis based on DEM. In this section, the uncertainty of DEM and terrain analysis caused by the above scales is classified into single scale effect, cross scale effect and boundary effect. One area of terrain analysis that has been largely ignored is the effect of variability of terrain within the bounds of single grid cell that is referred to the heterogeneity effect of DEM grid size in the paper.We pointed out those and discussed the effect on terrain analysis. At the end of this section, the scale threshold which can be used to indicate the effective extend of terrain attributes is discussed. It is known that the existing DEM with fixed resolution does not always meet the requirement of application. This means that one can deduct more scale terrain models from a fixed resolution DEM. In fact, scaling model can realize the terrain information allocation and aggregation in terrain analysis based on DEM. In this paper, three scaling models including scale deduce model, scale inversion model and multi-scale terrain analysis model are discussed.
    References | Related Articles | Metrics
    Analysis of error propagation and uncertainties in urban cellular automata
    LI Xia, Anthony Gar-On Yeh, LIU Tao, LIU Xiao-ping
    2007, 26 (3):  443-451.  doi: 10.11821/yj2007030003
    Abstract ( 2026 )   PDF (1060KB) ( 1727 )   Save
    The issues of data errors, error propagation and model uncertainties are important but often neglected in urban CA models.This paper has examined and addressed some of these issues by carrying out experiments with GIS data. Many model errors are related to model configurations, i.e. how to define a proper model to reflect the real process of urban development. This study demonstrates that some of them, however, are quite unique to CA: 1) data source errors will be reduced during simulation because of the averaging effects of neighborhood functions; 2) simulation errors will decrease with time because the availability of land suitable for urban development will be decreased in constrained urban CA as the urban areas grow in size; 3) the number of time steps (iterations) can cause different spatial patterns and simulation closer to actual development can be achieved with the increase in time steps; and 4) the major uncertainties of simulation are mainly found at the edge of simulated urban areas. These characteristics are quite different from those of general GIS modeling. The study shows that errors and uncertainties of urban CA are less severe than what one would normally expect from a simulation model. The uncertainties of the simulation will be reduced if more amounts of land are developed and the uncertainties are mainly located at the urban fringe. The findings of the study can help urban modelers and planners to understand more clearly the characteristics of errors and uncertainties in urban CA so that they can be used more effectively in urban planning.
    References | Related Articles | Metrics
    The relationship between population pressure growth and environmental change in recent 600 years in the upper reaches of the Fenhe River
    WANG Shang-yi, REN Shi-fang, MENG Wan-zhong
    2007, 26 (3):  452-460.  doi: 10.11821/yj2007030004
    Abstract ( 1541 )   PDF (643KB) ( 1720 )   Save
    The aim of this study is mainly to deal with the impact of human farming activities on the environmental changes especially the soil erosion in the upper reaches of the Fenhe River in recent 600 years.Through field investigation and the analysis of the long-term data of hydrology and landscape, the authors used the historical documentation method to make a quantitative analysis and estimate farming population, farmland and soil erosion development process of the study area. The study indicates that: (1)In recent 600 years, the population of the area increased by 716%, while the farmland merely 432%. So the farmland per capita available decreased by 34.8%. At the same time, per mu (15mu=1ha) average corn yield mu was only about 50kg lower than that in the middle reaches of the Yellow River in the Han Dynasty.The trend of reclamation still exited. (2)Through the analysis of the result of land measurement of Yangqu county in later Qing Dynasty, we thought the data of farmland area were far less from the actual amount, which was possiblely less than the half. (3)From the Qianlong to the Guangxu years of the Qing Dynasty, soil erosion amount increased because of slope farming, which was only 2%~3% of the total eroded amount and cannot play the dominant role. (4)From the Guangxu years of the Qing Dynasty to modern times, much scarp and steep slope land was reclaimed in the Fenhe river basin which led to the soil erosion increased to 30% of the total amount.But the amount of the gully erosion induced by natural force was also 70%. So the farming activity was merely the second factor for the soil erosion.
    References | Related Articles | Metrics
    A method for calculating potential productivity of main crops in dry farming system as well as assessment of agricultural resources utilization in temperate zone, NortheastChina: A case study of Hailun County, Heilongjiang Province
    DAI Er-fu, WANG Hao, WU Shao-hong, JIN Jing
    2007, 26 (3):  461-469.  doi: 10.11821/yj2007030005
    Abstract ( 1743 )   PDF (1451KB) ( 1981 )   Save
    This paper combines PS123 model with ordinary methods into a comprehensive model to calculate the main crops potential productivity from 1999 to 2001 in Hailun County, so as to propose a more objective and scientific method to calculate crop potential productivity. The photosynthesis potential productivity (PPP) is calculated by the equation established by HUANG Bingwei. The temperature potential productivity (TPP) and climate potential productivity (CPP) are determined by PS123 model. And land potential productivity (LPP) is calculated by multiplying an effective coefficient, which is decided by AHP approach. At the same time, based on the productivity of different levels, agricultural resources utilization assessment model is also established which is composed of productivity loss value, contented index and utility ratio. By this way it can be found the main restricting resource factors and the restricting degree to achieve the purpose of appraising agricultural resources utilization efficiency comprehensively. The result shows that in natural resources temperature restricts productivity most, then moisture condition and soil fertility condition. If TPP is regarded as the highest productivity that can be realized, then the TPPs of maize, soybean and wheat are 11998,7068 and 8813kg/hm2, their resources use efficiencies are 51.0%,29.0% and 20.2%,there is still great potential on main crops in Hailun County. To improve the productivity, on the one hand, perfect farmland capital should be constructed, and fertilizer and water input should be performed to remedy the deficiency in the natural resources. On the other hand, the enthusiasm of peasants to agricultural production should be aroused, and their educational level should be improved for the easier adoption of new technology, fine seeds and the planting system and planting way should also be improved to higher resources utilization efficiency. At the same time, there still exists difference between crops in the need of agricultural resources. Following the characteristics of different crops to invest resources can distribute resources rationally to obtain higher product.
    References | Related Articles | Metrics
    Endemia effects and impacts of geological background onsoil elements distribution and effects of endemic diseasein the Three Gorges Reservoir District
    ZHONG Yuan-ping, TANG Jiang, WANG Li
    2007, 26 (3):  470-476.  doi: 10.11821/yj2007030006
    Abstract ( 1700 )   PDF (217KB) ( 1920 )   Save
    Based on testing results of top-soils in the Three Gorges Reservoir District, distribution characteristics of element contents in soils were discussed by different types of parent rocks, such as mudstone and limestone. It can be concluded that, in the Three Gorges Reservoir District, the soils in the limestone areas are abundant in most of the elements, such as As,Br,B,Sb,C,F,I,Li,Mo,CaO and so on,which are more than twice the contents in soils rooting in mudstone areas. On the other hand, the soils in the mudstone districts are poor in most of the elements. Only several elements, such as Ba,P,Sr,Na2O,SiO2, are higher in contents than those in soils of limestone areas.The difference in elements distribution characteristics is closely related with the distribution of endemic fluorosis and Keshan disease in the Three Gorges Reservoir District. Endemic fluorosis mainly occurs in areas where soil content of fluorine is higher, which is the outcome of limestone-weathering and soil-forming process. And Keshan disease mainly happens in the lower-selenium soils areas, which is the result of mudstone-weathering and soil-forming process. Geological environmental conditions are responsible for the incidence of the endemic diseases in these areas. The research results can provide important reference to rational allocation of agriculture and rational planning of rural-urban areas in the Three Gorge Reservoir District.
    References | Related Articles | Metrics
    Application of redundancy analysis in predigesting sedimentary proxies for paleolimnological research: A case study of Taibai Lake
    DONG Xu-hui, YANG Xiang-dong, LIU En-feng, WANG Rong
    2007, 26 (3):  477-484.  doi: 10.11821/yj2007030007
    Abstract ( 2788 )   PDF (478KB) ( 1816 )   Save
    Taibai Lake, a shallow lake with a surface area of 26.1 km2, is a presently algae-dominant lake and experiences obvious eutrophication. A multi-proxy analysis including diatoms, pollen, grain size, magnetic susceptibility and selected elements were applied to a 50 cm long sediment core extracted from Taibai Lake. Series of multivariables analysis such as canonical correspondence analysis (CCA), redundancy analysis (RDA) based on those proxies revealed that the minimum variables combination including Pinus percentage, sediment phosphorus, frequency-dependent susceptibility and total organic carbon percentage could explain significantly most of the variation of diatom community, which could reflect the changes of lake's nutrient status. The four proxies explained 51.5% of the diatom variance, only 6.4% less than those explained by all the sedimentary proxies, which is 57.9%. Based on the four indices mentioned above and the reconstructed historical total phosphorus concentration, four developmental phases were distinguished as follows. (1) 1800-1863AD: the earlier deforestation led to much intensive erosion, which resulted in much nutrient input. While the lake kept lower nutrient status as nutrient concentration was diluted by the sufficient precipitation. (2) 1863-1924AD: the lake was still in a mesotrophic status for the weakened human impacts. (3) 1924-1970AD: human activities became stronger and nutrient input increased. However with the flourish of aquatic plant, parts of nutrient were absorbed and consequently the nutrient concentration increased slowly. (4) Since 1970 the lake has gradually become much obvious eutrophic with the development of much stronger human activities including reclamation, fish-stocking and modern agriculture, as well as the discharge of waste water from local factories and dwellers. The four phases were also illustrated clearly by the RDA bi-axis plot, which indicated different driving mechanism for lake environmental change in different periods. The sediment records in Taibai Lake showed that human activities played an important role in the recent eutrophication process. It also concluded that lakes with higher nutrient background is much apt to become eutrophicated enforced by human activities, consequently rational management or exploitation will be necessary to protect Taibai Lake from further water quality deterioration.
    References | Related Articles | Metrics
    Ecological effects of different road classes on landscape in the Lancang River valley
    LIU Shi-liang, WEN Min-xia, CUI Bao-shan
    2007, 26 (3):  485-490.  doi: 10.11821/yj2007030008
    Abstract ( 1629 )   PDF (598KB) ( 1654 )   Save
    The existence and extension of road networks affect adjacent landscape patterns and processes.The direct or indirect influences of ecological process caused by roads can extend from population to landscape level. Road development is a primary mechanism of fragmentation, removing original land cover, creating edge habitat, altering landscape structure and function, and increasing access for humans.Nowadays road ecology becomes a newly-emerging field in the ecologic research. Studies of the road effects on population and ecosystems were carried out in the past few years. But large scale research beyond ecosystem level has just been initiated.As series of potential ecological effects are brought out by landscape fragmentation due to road construction, it is significant to quantify the fragmentation features for management of road and its surrounding ecosystem.Meanwhile the regional ecological security attracts more and more attention as the road network expands.This paper focuses on the Lancang River valley and analyzes the relationship between ecosystem fragmentation and road construction and planning using GIS and FragStat software. By scenario analysis, the paper got the landscape change with seven road construction scenarios. The results show that the first level roads affect the largest area, next is the second level while the third level roads affect the least. The sequence of affected patch number is first level road > second level road > third level road > expressway. For the different ecosystems, the effect shows similar tendency and the area order is forest > grassland > arable land > shrub land > paddy field > construction land and patch number is arable land > forest.Scenario analysis showed that in the Lancang River valley road network development results in the increase of patch complexity and landscape fragmentation, also the trend suggests that the third level roads have larger effect on fragmentation.The average patch area decreases while the patch number and fractal dimension increase with the actualization of road construction and planning.But the expressway affects little in general. The results suggest that expressways may affect the larger ecosystem area, but they have far less effect on regional landscape fragmentation. Soil eroded area sequence is first level road > second level road > expressway>third level road and the erosion intensity mainly exhibits middle level.
    References | Related Articles | Metrics
    Studies on decomposition of fine roots of Castanopsis carlesii and Cunninghamia lanceolatain Wanmulin Natural Reserve, Fujian province (1.Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101,China|2.College of Geography Science, Fujian Normal University, Fuzhou 350012, China|3.Graduate School of the Chinese Academy of Sciences, Beijing 100039, China )
    JIN Zhao, YANG Yu-sheng, DONG Yun-she, QI, CHEN
    2007, 26 (3):  491-499.  doi: 10.11821/yj2007030009
    Abstract ( 1777 )   PDF (1604KB) ( 3444 )   Save
    Decomposition of fine roots plays an important role in carbon turnover and nutrients cycling in forest ecosystems. To date, several methods have been suggested to study the decomposing process of fine roots: (1) litterbag; (2) intact soil core; (3) minirhizotrons and so on. The method of litterbag is commonly used worldwide for researching on the process of decomposition of fine roots, and its primary disadvantage is strongly disturbing in situ conditions which may result in an underestimation of decomposition rate of fine roots. Intact soil core is another technique for researching on the fine roots decomposition. The major disadvantages of this method are laborious in sampling and different greatly among samples. Minirhizotrons is an advanced technique for studying the decomposition of fine roots, but may overestimate the decomposition rate. Therefore, the greatest challenge in study of fine-root decomposition is to design efficient experiments and develop new techniques. In this study, we applied the method of carborundum tube widely used in agriculture ecosystem into forest ecosystem to study the decomposing process of fine roots of C.carlesii, C.lanceolata(chinese fir) and their mixed samples, and compared it with the method of litterbag. The experimental site is located at Wanmulin Natural Reserve(27°03'N, 118°09'E)in Fujian province. This experiment was conducted from May 2002 to May 2004. Through two years’ experiment, the results show that: (1) fine roots of C.carlesii decomposed fastest in its community with the two decomposition methods, and its monthly decomposition rates are 0.0052(0~1 mm)and 0.0080(1~2 mm). In addition, fine roots of C.carlesii and its mixed samples decomposed in C.carlesii community show that the decomposition of 1~2 mm diameter is faster than 0~1 mm diameter; fine roots of chinese fir and its mixed samples decomposed in chinese fir plantation laws contrary. Soil condition and biochemical quality of fine roots are the main factors affecting fine roots decomposition. (2) The results of the two methods can be better fitted by Olso negative exponential equation and the fitted decomposition indicators shows small difference between the two methods. In subtropical forest ecosystems, carborundum tube method can be applied to study fine-root decomposition.
    References | Related Articles | Metrics
    Spatial characteristic of vegetation change in the source regions of the Yangtze River, Yellow River and Lancang River in China
    ZHANG Yi-li, DING Ming-jun, LIU Lin-shan, WANG Zhao-feng, YAN Jian-zhong, BAI Wan-qi, ZHENG Du
    2007, 26 (3):  500-507.  doi: 10.11821/yj2007030010
    Abstract ( 2249 )   PDF (605KB) ( 2373 )   Save
    The source regions of the Yangtze River, Yellow River and Lancang River are located in the middle east of the Tibetan Plateau with a total area of about 198496 km2. In recent years, the risk of vegetation degradation in the regions has been keeping increasing, which led to many negative effects. This study assessed the trend and temporal-spatial distribution of vegetation index change, which is related with vegetation degradation, in the source regions of the three rivers using multi-temporal NOAA AVHRR NDVI data (8 km spatial resolution) from 1981 to 2001 provided by NASA, DEM data (1 km resolution), roads, residents, rivers data (1 ∶ 250000) and collected field data. Data types converting and reclassifying and zonal statistic analysis are completed in Arcgis 9.0 software. Results show that: ①The decrease, improved and the invariant vegetation index occupied 18.92%, 13.99% and 67.09% of the whole study area respectively. ②The decrease rates of brush, needle-leaf forest, alpine meadow, alpine sparse vegetation and alpine steppes are 22.15%, 20.75%, 18.83%, 18.73% and 18.6% respectively; on the different frozen soil types, the decrease rates differ insignificantly.The vegetation index decrease rates on permafrost and seasonal-frozen ground are 19.78% and 19.41% respectively; the decrease rates are relative to the population density and livelihoods. ③The decrease rates are different in space, which in the source regions of the Yangtze River, Yellow River and Lantcang River are 13.56%, 32.51% and 18.1% respectively. ④The nearer to the roads and water sources is, the higher the decrease rates are; but to the distance buffers of the residents, the decrease rates rise with distance expending, and reach the top when arriving at the 24 km. ⑤The trend of decrease rates is according to the settlements density in different elevation zones with the correlation coefficient of 0.78. ⑥The vegetation decrease is highly related with the activities of human beings in the source regions of the Yangtze River, Yellow River and Lancang River.
    References | Related Articles | Metrics
    Comparison of sediment and runoff yield processes between different geomorphic regions in the Wudinghe River Basin
    WANG Sui-ji
    2007, 26 (3):  508-517.  doi: 10.11821/yj2007030011
    Abstract ( 1939 )   PDF (413KB) ( 1705 )   Save
    The Wudinghe River Basin is a representative basin in the eolian-loess transitional zone of the Loess Plateau. Some projects actualized during the last three decades for soil and water loss has led the sediment and runoff processes of the river basin no longer being in a pure natural state but also affected by anthropogenic activities.In order to put forward effective measures to prevent soil and water loss, it is necessary to find the natural processes of sediment and runoff yield of the Wudinghe River Basin. In this work the varying processes and rules of sediment and runoff yield in the eolian and loess hilly-gully regions of the river basin were analyzed systematically according to the data measured in a certain period of time before 1970 because limited human activities had been thrown to the river system during this period. The results are as below. In the near natural state the varying ratio of discharge of the river in the eolian region is smaller than that in the loess hilly-gully region.The river sediment concentration in the eolian region is far smaller than that in the loess hilly-gully region, accordingly, sediment delivery ratio is very high in the rivers of the loess hill gully region but inappreciable in the rivers of the eolian region. The specific runoff yield of the rivers in both eolian and loess hilly-gully regions is very close, but great disparities of the specific sediment yield occur in different regional rivers: it is 118.58~725.38 t/km2 · a for the eolian region and 1879.36~25112.15 t/km2 · a for the loess hilly-gully region. Obviously, the tributaries located in the loess hilly-gully region are the main source of the sediment yield in the Wudinghe River Basin. So, these tributary basins are the main regions needed to prevent soil and water loss and the control of sediment yield in gullies of these tributaries is the key task.
    References | Related Articles | Metrics
    Fractal dimension of soil particle size distribution during the process of vegetation restoration in arid sand dune area
    JIA Xiao-hong, LI Xin-rong, LI Yuan-shou
    2007, 26 (3):  518-525.  doi: 10.11821/yj2007030012
    Abstract ( 1871 )   PDF (335KB) ( 1883 )   Save
    This paper analyses the relationships etween the fractal dimension of soil particle size distribution, sand content, silt content, clay content and soil properties during the process of vegetation restoration in arid sand dune area. The result showed that fractal dimension of soil particle increased during the process of vegetation restoration with soil texture getting thinner and fertile.The longer the time of vegetation restored, the greater the fractal dimension of soil particle, the higher the <0.05mm content. The fractal dimensions tend to decrease with the texture coarser at the soil profile. Fractal dimension and soil texture have significant difference within different soil layers. There is a significant positive linear correlation between fractal dimension and the content of <0.05mm soil matter (p<0.0001), and a negative linear correlation between fractal dimension and >0.05mm content. So, <0.05mm content of soil particle size can be regarded as a critical diameter for determining fractal dimension which reflects the content of distribution of particle size fraction, the more the <0.05mm content, the higher the fractal dimension; adversely, the more the >0.05mm content, the lower the fractal dimension. With soil particle size getting thinner, the soil fertility changed remarkably associated with the process of sand dune stabilization. There are significant positive linear correlations between fractal dimension with all soil nutrient status (p<0.0001). Fractal dimension acts as a synthetical index. There a remarkable positive linear correlation with soil properties (p<0.0001).Therefore, the fractal dimension could be used to describe the texture and fertility states, evaluate degree of vegetation restoration in the arid sand dune area, and could be used as an integrated quantitative index to evaluate the degree of soil succession with the re-vegetation practice.
    References | Related Articles | Metrics
    Multi-scale study on climate change for recent 50 years in Dari County in the source regions of the Yangtze and Yellow rivers
    CHEN Ke-long, LI Shuang-cheng, ZHOU Qiao-fu, XIAO Jing-yi
    2007, 26 (3):  526-533.  doi: 10.11821/yj2007030013
    Abstract ( 1933 )   PDF (2116KB) ( 2418 )   Save
    Wavelet analysis, known as "Mathematical Microscope", has become a new mathematical approach in recent 20 years, being applied widely in many fields. Especially, with the significant advantage of characteristic of variable scale, it is suitable and effective enough to demonstrate the multi-scale traits of climate change, such as temporal series of temperature and precipitation. Accordingly, in this paper, Mexican Hat Wavelet is used to analyze the multi-scale characteristics of the climate change in Dari County, based on the temperature and precipitation of instrument data for 588 months during 1956~2004. Consequently, the periods and turning points of temperature and precipitation series in different time-scale are revealed, and the primary periods determined are 3 years or 4 years in a small scale and 16 years in a large scale. Meanwhile, the wavelet coefficients patterns exhibit a probable increasing trend in temperature and humidity in the following years. In the past 50 years, the temperature climbed to peak values for 3 times with the maximum at the beginning of the 21st century, and the precipitation is 2 times with the maximum in the early years of the 1980s. In general, the tendency of temperature and precipitation in Dari County is approximately consistent with that on the Tibetan Plateau and the source regions of the Yangtze and Yellow rivers except for some local lags in several periods. Changes in underdecadal scales are nested into complicated background in larger scales. The turning points varied along with the time-scale. According to the above analysis, we can conclude that there is a significant advantage of wavelet analysis in revealing the multi-scale characteristics, the primary period, and forecasting the trend of climate change in the following years.
    References | Related Articles | Metrics
    Climatic suitability for tourism along theQinghai-Tibet Railway
    CHANG An, GE Quan-sheng, FANG Xiu-qi, XI Jian-chao
    2007, 26 (3):  533-540.  doi: 10.11821/yj2007030014
    Abstract ( 1526 )   PDF (671KB) ( 1555 )   Save
    Qinghai-Tibet Railway, built through the high frigid plateau in western China, can considerably improve the traffic conditions of the districts along it. There are a great deal of world-class tourism resources along this railway. So, after the Qinghai-Tibet Railway is open to traffic the districts along it may become hotspots of tourism. On the occasion, tourism along the railway will spring up. However, some restricting factors such as climate condition, thin air, low atmospheric pressure and strong ultraviolet radiation may form obstacles in tourism development. It is a pity that, still now, tourism-climate research along the Qinghai-Tibet Railway is nearly blank. Taking into account all the above unfavorable conditions and based on the meteorological data covering the period 1991-2000 from 10 weather stations,this paper assessed climatic suitability for tourism along the Qinghai-Tibet Railway and intended to offer some scientific basis for the tourism development. In this paper, air temperature (as well as effects of humidity, wind velocity and sunshine hours are also considered), ultraviolet radiation, atmospheric pressure and disasterous weather are respectively analyzed as the index of climatic suitability for tourism. It is found that, (1) as a whole, May to September is the most suitable season of tourism along the Qinghai-Tibet Railway. There are neither hot nor cold, windy days in this season. But in the duration there are relatively frequent strong ultraviolet radiation, thunderstorm and hailstone. (2) With the rise of altitude suitable days and hours for tourism are shortened.Along the Qinghai-Tibet Railway, Lhasa and Xining, the terminals of the railway, are most suitable for tourism.However, Wudaoliang, Tuotuohe and Anduo have the shortest period with suitable climatic conditons for tourism because of cold weather (winter) and strong ultraviolet radiation (June, July).
    References | Related Articles | Metrics
    Calculation of rainfall erosivity by using hourly rainfall data
    YIN Shui-qing, XIE Yun, WANG Chun-gang
    2007, 26 (3):  541-547.  doi: 10.11821/yj2007030015
    Abstract ( 2788 )   PDF (1479KB) ( 2436 )   Save
    Rainfall erosivity shows the potential ability of the soil loss caused by rainfall and it is a very important factor for predicting soil loss from agricultural hillslopes. EI30 is a widely used index for quantifying rainfall erosivity. The 'E' portion of this value represents the rainfall energy, and the 'I30' portion represents the maximum, contiguous 30-minute rainfall intensity during the storm. Normally, EI30 values are calculated from breakpoint rainfall information taken from continuous recording rain gauge charts, however, in many places in China the detailed chart-recorded rain gauge data relative to storm intensities are not readily available. Obviously, the more detail of the rainfall data was used, the more accurate of EI values were given. In order to take advantage of hourly rainfall data in automatic meteorological observation stations and improve the precision of EI values. A total of 456 storm events in 5 soil conservation stations over eastern China were used to determine if EI values could be calculated by using hourly rainfall data (60-min interval data). Results indicated that the values of EI30 based on the 60 min interval data were less than those calculated from breakpoint data. The average conversion factors (ratio of values calculated from the breakpoint data to those from 60 min interval data) for the five stations are 1.105 for the estimation of E values, 1.668 for I30 values, and 1.730 for EI30 values. The differences between two kinds of EI values based on breakpoint data and hourly rainfall data are mainly caused by maximum 30-min rainfall intensity. Hourly rainfall data can be used to accurately determine the rainfall erosion index values by using this function:(EI30)bp=1.730(EI30)60.The result could be used to improve the estimation of rainfall erosivity indices, and hence prediction of soil erosion in China.
    References | Related Articles | Metrics
    Club convergence of regional economicgrowth in Henan Province
    QIN Cheng-lin, TANG Yong
    2007, 26 (3):  548-556.  doi: 10.11821/yj2007030016
    Abstract ( 1969 )   PDF (1947KB) ( 1841 )   Save
    The spatial relationships of regions are a very important factor affecting club convergence of regional economic growth. By using the method of Markov chains, we have studied the club convergence of regional economic growth in Henan province, China from 1990 to 2004. We defined the spatial relationships of regions for neighbor regional environment, and then, have studied its influence on the club convergence of regional economic growth in Henan province in the same period using spatial Markov chains. The results show that there were four convergence clubs of regional economic growth in Henan province during 1990~2004, namely, high income club, middle-high income club, middle-low income club, and low income club. The spatial distribution patterns of the four convergence clubs were that high income club located mainly in central regions and northwest border regions of Henan province presents a C-shaped pattern with Zhengzhou, Luoyang and Jiaozuo as its pivot. The middle-high income club was mainly around the high income club. The low income club is a Y-shaped region that was composed of two parts, one was the east plain of Henan to the east of Beijing-Guangzhou railway, and the other was a northwest-southeast zone with low income in the west of Henan. The middle-low income club was relatively dispersed in space, mainly in Nanyang basin, as well as the border regions in the north of Henan. The high income club and low income club were more steady and expanded continuously in space. The levels and spatial structure of regional economic growth in Henan province have been more and more polarized. As a whole, the neighbor regional environment of a region had influences regularly on its economic growth and its transfer path from one convergence club to another. The economic growth and the probability of transferring into middle-low income club of a low income region were correlative with the economic growth levels of its neighbor regions positively. The middle-low income regions tended to be into low income convergence club. If its neighbor regions were with higher economic growth levels, the probability transferring into high income club of a middle-high income region was higher. Whereas, if the economic growth levels of its neighbor regions were lower, the probability of transferring into middle-low income club of a middle-high income region was higher. The economic growth and its steadiness of a high income region were less influenced by its neighbor regions. In addition, the regions that transferred from a club to another almost congregated in two or more than two regions in space.
    References | Related Articles | Metrics
    Formation and evolution of world container ports system and coupling mechanism with international trade networks
    WANG Cheng-jin, YU Liang
    2007, 26 (3):  557-568.  doi: 10.11821/yj2007030017
    Abstract ( 1997 )   PDF (821KB) ( 2023 )   Save
    Marine container transportation is an important research field in Transportation Geography and has become the key support factors of international trade. In this paper, based on expounding about international and domestic research history of container seaports and seaports systems, the author took the world top 100 ports and data of the years of 1970-2003 as the studying objects, and discussed the developing and evolution course of world container seaports system.Then the author designed an index to appraise the spatial aggregration of world container transportation and container seaports, and their developing trends, including marine container transportation aggregration of port, region and country.In order to examine the developing mechanism of world container seaports system, the author analyzed the spatial coupling mechanism between world container seaports and international trade networks, through analyzing the international trade O-D data of the years of 1970-2003.Through research, the author drew the following conclusions.(1)World container seaport system witnessed the development course of "North American and West European port cluster→North American, West European and East Asian port cluster→East Asian port cluster→Chinese port cluster ".(2)There is the time period of spatial aggregration and diffusion about the world sea container transportation and now in the initial stages of spatial aggregration time, and the East Asian region became the world container transportation center.(3)Economic factors, shipping lines and port locations are the main driving factors for the development and formation of the world container seaport system,especially there is a coupling mechanism between the international trade networks and world container seaport system.
    References | Related Articles | Metrics
    Study on the relationship between economic growth andenvironmental pollution based on the Weibull andGamma specifications
    SONG Tao, ZHENG Ting-guo, TONG Lian-jun
    2007, 26 (3):  569-576.  doi: 10.11821/yj2007030018
    Abstract ( 1871 )   PDF (449KB) ( 1995 )   Save
    In the past twenty years, the Environmental Kuznets Curve has been regarded as one of the most powerful tools in studying the relationship between economic growth and environmental pollution. Conventional studies usually use the linear model or the log-linear model to examine the existence of the Environmental Kuznets Curve. However, from analytical viewpoint and empirical behavior, the performance of the linear model or the log-linear model is suspected for their strict restrictions, such as linearity, nonnegative property, and symmetry. Consequently, conventional linear methods for the Environmental Kuznets Curve studies can not be a fine econometric tool. With a view to the above shortcomings in describing the Environmental Kuznets Curve with the linear model and the log-linear model, this paper investigates the relationship between economic growth and environmental pollution in China, using panel data models with the Weibull specification and the Gamma specification, where all the three parameters are used to describe the "shape", "scale" and "shift" of the curves, respectively. In this study, we select per capita waste water emission, per capita waste gas emission and per capita solid wastes generated as the environmental indexes, and per capita gross domestic product (GDP) as the income index with the 29 provincial data over the period from 1989 to 2005. The results show that panel data models with the Weibull specification and the Gamma specification are both simulated better than that with the log-linear model, and their parameters have good explanatory capability. It is also suggested that with the rise of per capita income, per capita waste water emission in China first increases and then decreases, appearing a turning point around 25 000 yuan, while per capita solid wastes generated and per capita waste gas emission take on monotonously increasing relationships which have quite high income turning points.
    References | Related Articles | Metrics
    Spatial impacts of New Economies and the implications for city planning and decision-making
    WANG Hui
    2007, 26 (3):  577-589.  doi: 10.11821/yj2007030019
    Abstract ( 1880 )   PDF (328KB) ( 2847 )   Save
    The rise of New Economies, which refer to those knowledge-based, new-technology-intensive, innovation-driven, services-dominated, and globalized economic activities, has been impacting on cities in many aspects. Taking the city of Xi'an as a case, viewed from a perspective of urban geography, based on a variety of empirical data as well as some widely acknowledged understandings of the inherent features of New Economies, some representative spatial impacts (or potential impacts) of New Economies on the ongoing urban transformation of Chinese cities are analyzed in this paper. Besides, the implications of these impacts for city planning and decision-making are also discussed, and some suggestions on policies are given accordingly. The results indicate that: (1) with the development of New Economies, the spatial pattern of the city's industrial space has been transformed, in which the city's new development zones and university belt are growing up into vigorous and productive new industrial spaces, while the traditional old industrial districts declining into stagnant and problematic areas; (2) with the development of New Economies, there has been also an evident growth of office-buildings and relevant facilities; (3) because of the inherent connection between the two major branches of New Economies, i.e. the hi-tech industries and the advanced producer services, the city's Hi-tech Industrial Development Zone (HTDZ) are developing not only into a cluster of hi-tech industries but also a high concentration of various modern services and emerging as the city's new CBD; (4) the compatibility of New Economies with residential plots has led to a synchronous development and spatial integration of New Economic area with residential area;and (5) with the development of New Economies, there may also be an intensified polarization of urban socio-economic space.
    References | Related Articles | Metrics
    Spatial analysis of economic growth convergence mechanism in Beijing-Tianjin-Hebei Metropolitan Region
    MA Guo-xia, XU Yong, TIAN Yu-jun
    2007, 26 (3):  590-598.  doi: 10.11821/yj2007030020
    Abstract ( 1732 )   PDF (1629KB) ( 1789 )   Save
    The question of regional convergence is of great interest to regional scientists,but the majority of empirical studies of regional convergence in literature have been focused on the traditional convergence methods in which the geographic entities are treated as "isolated islands" and have not explicitly considered the regional spatial dependence. In this paper, methods of exploratory spatial data analysis and spatial autocorrelation model provide new insights to explore spatial dependence relation of Beijing-Tianjin-Hebei Metropolitan Region over the 1992~2003 period. Furthermore, using spatial econometrics, income convergence was computed by using three different models, which are spatial lag model, spatial error model and traditional convergence model. Some results are drawn as follows: (1) Spatial dependence plays an important role in analyzing regional income convergence. The application of exploratory spatial data analysis methods revealed strong evidence for spatial dependence of regional economic growth and improved traditional convergence model. (2) The specification of traditional convergence model is misspecification due to ignoring spatial dependence. Spatial lag model and spatial error model,which take spatial lagged dependent variables and spatial lagged error terms into account based on traditional convergence model, optimize the structure of model, and give helpful hints of the meaning of convergent economy-policy. (3) A spatial analysis of Moran scatter plot of GDP per capita indicates that economic growth is also highly spatial dependence in Beijing-Tianjin-Hebei Metropolitan Region between 1992 and 2003, namely, a high income county with high income neighbors and a low income county surrounded by low income neighbors. (4) Beijing-Tianjin-Hebei Metropolitan Region converges to a specific steady-state in GDP per capita from 1992 to 2003.At the same time,Beijing-Tianjin-Hebei Metropolitan Region is the phase of polarization and economic disparity is big,the rate of convergence is small.
    References | Related Articles | Metrics
    The effect analysis of Nanjing city-port interactive development under the background of globalization
    LIANG Shuang-bo, CAO You-hui, WU Wei, CAO Wei-dong, YUAN Hui-li, LI Chuan-wu
    2007, 26 (3):  599-608.  doi: 10.11821/yj2007030021
    Abstract ( 1811 )   PDF (375KB) ( 1465 )   Save
    It is of great significance, both theorefically and practically, to study the change of the port-city relationships. Under the background of globalization, the relationships between ports and cities have become more complicated and subtle than at any time, and can be summarized as follows: Firstly, the relationships based on handling cargoes have decreased, while financing trade relationships are increasing. Secondly, the change tendencies of different ports-cities may vary from one to another. In this paper, the author first analyzes the associative structure between port and city, and then use gray correlative analysis to measure the effect of Nanjing port-city interactive development under the background of globalization. A practical formula of the mean associative degree (MAD) is designed for determining the direction and degree of dynamic change of the port-city associative degree. By calculating the concerned statistics from 1990 to 2001, it can be clearly seen that MAD in 1990 is 0.68679, which is relatively high, then there appeared a steady tendency to drop. In 1994, MAD reached its minimum which is 0.63763, following a steady tendency to rise. In 1998, MAD reached its maximum which is 0.8853. But then an evident drop took place. According to these results, the authors hold that there are two obvious features of the effect: (1) On the whole, the effect of Nanjing port-city interactive development is relatively notable. (2) There are obvious differences in the change tendencies of the effect in the 3rd phase.A systematic analysis has been carried out on the formation causes of the effect change of Nanjing city-port interactive development. This paper holds that the following factors have profound implications on it: the change of industrial structure of Nanjing, the changing function of Nanjing port, the intense competition between the ports all around, the administrative system of port and the development of international trade.
    References | Related Articles | Metrics
    To discover the secret of traditional agriculture and serve the modern ecoagriculture
    LUO Shi-ming
    2007, 26 (3):  609-615.  doi: 10.11821/yj2007030022
    Abstract ( 782 )   Save
    Traditional Chinese agricultural heritage is one of the few cultural heritages that is continuously passed on for almost ten thousand years Because of its long history of development, there must be many internal mechanisms that let them survive after many natural and social changes. Industrial agriculture is a revolution from traditional agriculture Sustainable eco-agriculture is a revolution from industrial agriculture. This double revolution makes many experiences from traditional agriculture borrowed for our future agriculture However, traditional agriculture is quickly disappearing because of the wide use of industrial methods and its inadaptability to the changing world. The agricultural production system in the 1950s to the late 1970s also accelerated the loss of traditional experiences.
    Related Articles | Metrics
    Evaluation model of countryside tourism’s rural feature:A case study of Wuyuan in Jiangxi province
    FENG Shu-hua, SHA Run
    2007, 26 (3):  616-624.  doi: 10.11821/yj2007030023
    Abstract ( 1954 )   PDF (1411KB) ( 1787 )   Save
    Rural feature is the fundamental characteristic of countryside tourism. To carry out evaluation of rural feature can help to lay the foundation for the research of a sustainable development of rural tourism. It is also important for the development, operation and management of countryside tourism. Based on the analysis on the content of countryside and rural tourism, five major factors, namely, geographic condition, tourism resource, community participation, localization of tourism industry and sustainable development are identified. According to structural equation, a countryside feature evaluation model is proposed in which the variables of the causal link are connected with arrow path. Its relevance is expressed using coefficients (threshold >0,<0.95 ). In this essay Wuyuan in Jiangxi Province is used as an example. SPSS statistical software was used for the multiple regression analysis of the observation matrix of the sample; path coefficients and random errors were obtained. F test and fit test were conducted for each regression equation. The result shows a high reliability. T test was conducted for the path coefficient with t values between 2.319~86.895 and P values being P<0.01 or 0.05. The causal relationship in the model was obvious and in line with the assumption of the study. Thus the model can be accepted.
    References | Related Articles | Metrics
    Multi-level grey evaluation of tourism resourcesexploration potential: A case of Laozi Mountain Tourism Attraction
    WANG Xia, GU Chao-lin, LIU Jin-yuan, MEI Hu
    2007, 26 (3):  625-635.  doi: 10.11821/yj2007030024
    Abstract ( 1771 )   PDF (502KB) ( 1848 )   Save
    Tourism resources exploration potential evaluation can be defined as the capacity of tourism resources to develop tourism industry and to gain economic, social and environmental benefits. The evaluation of tourism resources exploration potential involves not only the value of tourism resources themselves, but also environment conditions and development benefits which are necessary for the tourism resources development.Ot the basis of the combination of AHP approach and Grey Theory, this article tries to innovate the evaluation approach of tourism resources exploration potential by applying the multi-level grey approach. In the empirical study, Laozi Mountain Tourism Attraction is taken as an example.First, key factors which have important influence on tourism resources are analyzed and then evaluation index system of tourism resources exploration potential is established. It consists of three hierarchies, and is composed of 12 indexes. Second, the tourism resources exploration potential of the above six scenic spots in Laozi Mountain Tourism Attraction are evaluated and sorted based on the multi-level grey approach. The study shows that the result of the multi-level grey evaluation of tourism resources exploration potential is objective and reliable; it doesn't require a large sample and is very effective to fill in the gaps such as inexact and incomplete evaluation information. In addition, this paper applies multi-level grey approach in the evaluation of tourism resources and makes a comparative analysis between the evaluation result of tourism resources and that of tourism resources exploration potential. The study indicates that there is difference between them, high rating tourism resources does not mean prospective exploration potential. The evaluation of tourism resources exploration potential is more comprehensive and is helpful to resolve the conflict between tourism resources rating and tourism resources exploration potential.
    References | Related Articles | Metrics