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Table of Content

    25 December 2004, Volume 19 Issue 6 Previous Issue    Next Issue
    Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    Nature·Water·Human
    CHEN Jia qi
    2004, 19 (6):  689-693.  doi: 10.11849/zrzyxb.2004.06.001
    Abstract ( )   PDF (58KB) ( )   Save
    Along with the progressive development of the human society,the human demand for the material support from nature is higher and higher.Meanwhile the disturbance to the nature resulted from humanity is increasing accordingly,and then the influence on the sustaining capacity of the natural world also increases,and so a tensile relation between humanity and nature appears.Therefore humanity should deal properly with the relations to the nature so that the human survival environment may not be imperiled.Water is the important element of the nature,and keeps an intimate relation with the existence of the humanity.Due to the successive increase of the amount of water uses and improper water utilization,water scarcity occurred in some places and regions.In work of mitigating the water induced hazards sometimes unsuitable measures can also aggravate the disasters.Therefore people should handle properly the relations with water conscientiously in the framework of dealing properly with the relations to the nature,so that sustainable utilization of water resources and sustainable development of the human society can be ensured.
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    Analysis of the relationship between runoff amount and its impacting factor in the upper Yangtze River
    LI Lin, WANG Zhengyu, QIN Ningsheng, MA Yucai
    2004, 19 (6):  694-700.  doi: 10.11849/zrzyxb.2004.06.002
    Abstract ( )   PDF (330KB) ( )   Save
    Based on the runoff amount and meteorological data of the corresponding period in 1963~2001 at Zhimengda hydro station of the upper Yangtze River,the variation law and its impacting factor of runoff amount in the Yangtze River is analyzed.The result shows that the runoff amount of the upper Yangtze River has been decreasing in the recent 40 years,in which the decrement in autumn is more significant with the elevation/increase of annual air temperature and evaporation,and the decrease of precipitation as well as climatic desiccation. These factors have become the main cause for the decrease of runoff amount,among which precipitation is the most important factor to affect runoff amount,the precipitation decreasing in summer has a very close relationship with the decrease of runoff in autumn,while the decrease of runoff in autumn causes the decrease of annual runoff amount.
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    An analysis of the groundwater system evolution charac-teristics in large interior basins of Northwest China
    XU Guangming, ZHANG Yanjun
    2004, 19 (6):  701-706.  doi: 10.11849/zrzyxb.2004.06.003
    Abstract ( )   PDF (275KB) ( )   Save
    Northwest China is lack of water resources and ecological environment is fragile.Owing to unreasonable development of water and land resources,many problems of ecological environment(such as land desertification,salinization,etc.)have occurred.The evolution law of groundwater system must be followed for improving ecological environment and reasonable exploitation and utilization of water resources.This thesis analyzes and compares the characteristics of the aquifer systems and groundwater runoff systems of the various large interior basins in Northwest China.The transformation modes of surface water and groundwater are identified using method of fuzzy mathematics.The result shows that the transformation modes are not only unanimous in form but also analogous in the proportion of transformed quantity.The impacts of hydrologic environment and human activity on groundwater cycle and evolution laws are discussed.Finally,the thesis gives some proposal about the rational exploitation and utilization of water resources in these basins.
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    Effects of land use change on groundwater quality in karst watershed-A case study in Xiaojiang watershed of Yunnan province
    JIANG Yongjun, YUAN Daoxian, ZHANG Gui, HE Raosheng
    2004, 19 (6):  707-715.  doi: 10.11849/zrzyxb.2004.06.004
    Abstract ( )   PDF (737KB) ( )   Save
    The environmental effects of land use/cover change will become the focus in the future. Based on 2 times spatial data of land use and water quality datasets of Xiaojiang watershed in 1982 and 2003,land use change map and land use matrix were made,and also a series maps on pH and hydro chemical features of common ions of groundwater and groundwater quality change map were achieved,supported by GIS and comprehensive evaluation of groundwater quality.It indica tes: (1)The transformed area was 610.12km2 or 59% of the total during the past 20 years in Xi aojiang watershed.The unused land transformed into cultivated land and forestland,and forestland transformed into cultivated were most important change,of which the transformed area was 475.29km2 or 77.9% of the total;the spatial pattern of land use in Xiaojiang watershed has changed greatly.With the increase of human disturbances,the diversity index,the homogeneity index and the broken index all increase,especially,the broken index increased by 84.6%. (2)As forestland transformed into cultivated and unused land transformed into cultivated,the total hardness,total alkalinity,pH,SO42-,NO3- and Ca2+ of groundwater increased obviously,and formed the high value zone.The I,II and III grades of groundwater quality area were 943km2 or 91.2% of the total area in 1982,but there were only 434.2km2 or 42% of the total area which were I,II and III grades of groundwater quality area in 2003.Obviously,the groundwater quality became worsened during the past 20 years in Xiaojiang watershed. (3)Changes of groundwater quality are related to the pollution of fertilizer resulting from increase of cultivated land and the degeneration of eco environment due to the worsening of forestland quality.There was a dynamic relationship between the groundwater quality change and the land use change. Therefore,based on the watershed served as research unit,the research of land use change and its effects of hydrogeologic environment are very important for the protection of the resources and environment of the karst region.
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    Flood & drought disaster and regulation of storm-runoff resources in Hunan Province
    LI Jingbao, WANG Kelin, ZHU Ning, LIANG Chengjun, LIU Jiewei
    2004, 19 (6):  716-724.  doi: 10.11849/zrzyxb.2004.06.005
    Abstract ( )   PDF (395KB) ( )   Save
    Based on synthetic analysis of the statistics of the flood & drought disaster conditions from 1950 to 2002 and the rainfall amount from 1956 to 1988 and from 1954 to 1998 in Hunan Province in combination with natural conditions of drainage basins and the current situation of water conservancy,several conclusions can be drawn.The alternative evolution tendency of flood & drought in hilly areas of Hunan Province becomes more and more evident,the flooding outside of and waterlogging inside of Dongting Lake area alternate frequently,rural population who have difficulties in getting drinking water increases constantly.The rainfall from July to September only occupies 20% of the year's total,contrarily,rainfall from April to September occupies 69%, and precipitation most frequently occurs in the form of storm runoff.And this precipitation characteristic is the sticking point leading to the water security problems.So,it is necessary to take measures such as making full use of the favorable landform to construct small scale flood retention and storage projects,to rehabilitate eco environment in an all round way,to bring into play the potential of reservoir groups in flood prevention and water conservancy works constru ction,and to enhance the adjustment levels of large reservoirs so as to effectively regulate storm runoff from April to August,mitigate flood & drought disasters,at the same time,to satisfy the water demands for water supply,power generation,navigation,tourism and so on.
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    Analysis on the shrinking process of wetland in Naoli River Basin of Sanjiang Plain since the 1950s and its driving forces
    HOU Wei, ZHANG Shuwen, ZHANG Yangzhen, KUANG Wenhui
    2004, 19 (6):  725-731.  doi: 10.11849/zrzyxb.2004.06.006
    Abstract ( )   PDF (758KB) ( )   Save
    Wetland is an important resource and it is the most suitable and important survivinge nvironment to human beings.Because of natural and anthropogenic influence,wetland is shrink ing extensively.Its function is declining.All these have threatened the sustainable development of human beings.Taken Naoli River Basin as an example,the wetland shrinkage in space and time and its driving forces are analyzed from 1954 to 2000.The results show that the area of wetland reduces from 1 149 878 hm2 in 1954 to 277 691.25hm2 in 2000.The percentage of area reduces from 45.85% to 11.07%.The area of wetland is only 1/4 of the original.On the other hand,the area of cultivated land increases from 206 003.5hm2 to 1 440 260.25hm2.The percentage of area increases from 8.21% to 57.43%.And the main driving force of wetland shrinkage in Naoli River Basin is the human activities reclamation.
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    Study on the dew resource in Sanjiang Plain
    YAN Baixing, DENG Wei
    2004, 19 (6):  732-737.  doi: 10.11849/zrzyxb.2004.06.007
    Abstract ( )   PDF (163KB) ( )   Save
    Change characteristic of dew days in Sanjiang Plain was studied and dew was in situ collected using the collectors of poplar sticks in soybean field and marsh land from May to Oct. 2003.Carex lasiocarpa is the dominant plant in marsh land.At the same time, temporal and spatial changes of dew content were analyzed,including seasonal change and vertical distribution between marsh land and farmland.Dewfall condenses mainly in summer and fall and the peak of dewfall appears in September.The number of dew days in the years of 1992~2003 ranged from 66 to 108,and the mean is 95.42.The dewfalls in July,August and September collected on the surface of soybean field were higher than those on that of marsh land,and the dewfalls in May,June and October were lower than those of marsh land.The dewfalls varied with the height and dewfall was the richest in canopy in marsh land,and vertical changes of dewfalls in soybean field were unconspicuous.The unit area actual dewfalls in marsh land and soybean field reached 20.68mm and 19.46mm in 2003,which accounted for 5.05% and 4.75% of the rainfalls of the same period,respectively.Dew plays an important role in keeping water balance of marsh ecosystem and farmland ecosystem,and may compensate the shortage of rainfall in growth season of crops.
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    Simulation of water potential productivity of winter wheat and soil water dynamics on rainfed highland of the Loess Plateau
    LI Jun, SHAO Mingan, ZHANG Xingchang
    2004, 19 (6):  738-746.  doi: 10.11849/zrzyxb.2004.06.008
    Abstract ( )   PDF (416KB) ( )   Save
    Based on introduction,calibration and validation,the EPIC model was used to simulate water potential productivity (WPP) of winter wheat and soil water dynamics on rainfed highland at Changwu of the Loess Plateau for medium term (12 years) and long term (30 years) assessment simulation research respectively.The results show that:1)during the 12 year simulation period under real time weather conditions,WPP of winter wheat on rainfed highland fluctuates and decliness along with precipitation changes,crop available soil water amount in 3m soil layer also fluctuates and declines evidently,and trend of soil desiccation is remarkable;2)during 30 year simulation period under simulated weather conditions,WPP of winter wheat on rainfed highland fluctuates along with precipitation but declines slightly,crop available soil water amount in 3m soil layer fluctuates seasonally and annually,but without remarkable soil desiccation;and 3)after integrated analysis,it is thought that soil desiccation of wheat field on rainfed highland is a short time phenomenon and usually won't continue long if decline trend of precipitation is insignificant,but fluctuation of wheat yield along with precipitation change is inevitable.
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    The effects of land use change on water resource in intensive agricultural region-A case study of Quzhou county in Hebei Province
    KONG Xiangbin, ZHANG Fengrong,QI Wei, JIANG Guanghui, YAN Guoqiang
    2004, 19 (6):  747-753.  doi: 10.11849/zrzyxb.2004.06.009
    Abstract ( )   PDF (186KB) ( )   Save
    s: In many developing countries, water resource is one of the major limiting factors to development.A reliable supply of sufficient good quality water is required for human consu mption,industry and irrigation.So a region's sustainable development is dependent largely on water resources,it is especially so in intensive agricultural region.Therefore,the effects of land use change on the region's water resource are of particular interest. In the last 50 odd years,Quzhou county has experienced great changes in land use,and the area of crops has increased substantially,leading to marked consumption of water resources. This paper studies the relationship between land use and water resource by taking Quzhou as a case. Based on the data from the statistics bureau and irrigation data on Quzhou county,we analyzed the land input change and its contribution to the per unit area crop yield and the balance of water resources.The result showed that the multiple cropping index,fertilizer input and the rate of irrigation had been improved.The simulated production function of crop showed that the guarantee rate of irrigation contributed the most to the crop yield,which was up to 0.546.The high dependency on irrigation led to the over exploitation of the water resources and the subsequent unbalance of the water resources.If this tendency continues,adverse effects on regional sustainable water use will be exerted.Such measures as reducing multiple cropping index,and reducing the wheat area should be taken to improve the sustainability of water resources.
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    Resource-environmental pressure analysis and ecological cybernetics response: A case study of coastal wetlands in Yancheng, Jiangsu Province
    LI Yangfan, ZHU Xiaodong, ZOU Xinqing, LIU Qingsong, GAO Jianhua
    2004, 19 (6):  754-760.  doi: 10.11849/zrzyxb.2004.06.010
    Abstract ( )   PDF (414KB) ( )   Save
    Coastal Wetlands in Yancheng (CWY),Jiangsu Province consist of two national natural reserves characterized by protecting red crowned crane and elk.Each developmental stage of the coastal wetland in this area is under the strong influences of human activities such as wetlands reclamation,irrational exploitation,water quality degradation,etc.All of these aggravated the pressure imposed on the coastal wetland area.This paper analyzes multiple kinds of environmen tal pressure,including population pressure,socio economic pressure,irrational exploitation pressu re,environmental pollution pressure,to explore relationships among resource environmental pres sure,state and response;for the purpose of using ecological policies to turn the ecosystems of the coastal wetlands to a healthy state.Based on ecological cybernetic responses and sustainable development,a framework with relevant measures is proposed in this paper as follows:(1) Ecologi cal planning and design.To identify an optimal allocation of its core zones,buffer zones and experimental zones in order to assure a clear conservation target of CWY,and convert some biodiversity hotspots into a core ecological preserve area.(2) Ecological engineering.To implement a number of wetland related projects (waterfowl lake,reed farms,fish ponds,et al.)in the buffer zone for gaining great economic benefits to maintain feedbacks to waterfowl ponds and in the ecotourism zone serving as a good supplement to preserve wetlands landscape.(3)Ecosystem management.Community co management is a new approach to natural reserve management.Com munity residents can benefit from the application of new agricultural technology and implementation of community development programs.Meanwhile,the conservation of bio diversity can be strengthened.
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    Woodland hydrological effects of spruce plantations and natural secondary series in sub-alpine region of western Sichuan
    ZHANG Yuandong, ZHAO Changming, LIU Shirong
    2004, 19 (6):  761-768.  doi: 10.11849/zrzyxb.2004.06.011
    Abstract ( )   PDF (212KB) ( )   Save
    Primary dark coniferous forests,dominated with firs and managed as a part of water con servation project in the upper reaches of the Yangtze River,were cut on a large scale from 1950 to 1980 in sub alpine region of west Sichuan,spruces were planted on most cutover area and native tree species regenerated naturally at the same time.The cumulated mass (CM) of moss and litters and the maximal water holding capacity (MWHC) of moss,litters and soil were measured by field investigation and soaking experiment to analyze the hydrological effects of spruce plantations with different ages and natural secondary series in sub alpine forest of west Sichuan.The result shows that MWHC of moss and litters,along with their CM,increases with the increment of forest age in spruce plantations and natural secondary series.CM and MWHC of moss and litters in 10 years and 30 years' old plantations are significantly higher than those in natural secondary series with same age.CM of moss and litters in 40 years' old spruce plantations are also significantly higher than those in natural mixed forest with same age,but MWHC between them are not significantly different.The maximal water holding rates (MWHR) of moss and litters in spruce plantations are lower than those in natural secondary series.After 70 years' restoration,the sum of MWHC between moss and litters in spruce plantation has been close to that in primitive fir forests.In all spruce plantations and natural secondary series,soil bulk density increases with the increment of soil depth,while MWHC,capillary water holding capacity (CWHC) and least water holding capacity (LWHC) decrease.MWHC of soil in 0~40cm depths are significantly different among spruce plantations with different ages,but the differences are not related with their ages and MWHC of soil don't increase along with the increment of ages.There are not significant differences in soil 0~40cm MWHC among natural secondary series.Hydrological effects of spruce plantations increase faster than those in natural secondary series,indicating that CM and MWHC of moss and litters in the former ones increase faster than those in the latter.
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    Ecological security assessment of Hainan Island
    XIAO Rongbo, OUYANG ZhiYun, HAN Yishi, WANG Xiaoke, LI Zhenxin, ZHAO Tongqian
    2004, 19 (6):  769-775.  doi: 10.11849/zrzyxb.2004.06.012
    Abstract ( )   PDF (310KB) ( )   Save
    Ecological security is one of the important footstones of national security, and is the base of sustainable development.Regional ecological security means that the ecological condition and the main ecological issue of a region does not threaten its survival and development with a given temporal spatial environment,at the same time the natural ecosystem service meets the needs of the regional survival and development.On the basis of comprehension and analysis of ecological security conception,the evaluation indices system is established including ecological products, eco environment situation,ecological function,and regional ecological security index and calculation model is put forward.Taking Hainan Province as an example and applying this assessment method,its integrative terrestrial ecological security index is 0.610.Among three assessing aspects,ecosystem services security is highest(0.772),security depending on resource is the lowest(0.468).The result indicates that the terrestrial ecological security is better in Hainan province especially in erosion controlling,natural disaster rejecting,air quality maintenance,etc. But there is also a lot of unsafe hidden trouble about energy sources self supporting ability,biodiversity protection,waste and sewage disposal,etc.It is believed that scientific and reasonable measures should be further strengthened,and safe ecosystem should be developed,so as to realize regional sustainable development.
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    Landscape patterns analysis based on APACK for Ejin natural oasis
    CAO Yu, OU YangHua, XIAO Duning, CHEN Gao
    2004, 19 (6):  776-785.  doi: 10.11849/zrzyxb.2004.06.013
    Abstract ( )   PDF (399KB) ( )   Save
    The Ejin natural oasis landscape lies in the lower reaches of the Heihe river basin in the arid interior regions of northwestern China.With decreasing water resources from the upper reaches of the Heihe river basin,many urgent ecological and environmental issues in the Ejin natural oasis have become more pressing in recent years.Analysis on landscape patterns not only can clarify the characteristics of the natural oasis landscape spatial structures,but also can provide a scientific basis for the study of the landscape degradation,protection and its sustainable development.Using remote sensing techniques,GIS,and landscape pattern analysis software APACK,the landscape patterns of Ejin natural oasis landscape are studied respectively from the aspects of area statistics,indices at landscape level,indices at classes level and indices between attribute classes based on Landsat 7 Enhanced Thematic Mapper plus data in 2001.Moreover,correlation analysis between different landscape indices is carried out with the integration of Ejin natural oasis landscape indices in 1987,1994 and 2001.Results show that: 1) typical"matrixcorri dor patch" landscape structure was shown in Ejin natural oasis landscape; 2) it was not steady for Ejin natural oasis landscape with high fragmentation,low landscape diversity,and coarse land scape texture; and 3) it was not independent of each other between different landscape indices,and the relations between some of the indices was obviously correlated with each other.Furthermore,the authors suggest that it should be careful to select some of the landscape indices during landscape patterns analysis.
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    Study on eco-environment carrying capacity: A quantifying method and case study in the Haihe Basin, China
    XIA Jun, WANG Zhonggen, ZUO Qiting
    2004, 19 (6):  786-794.  doi: 10.11849/zrzyxb.2004.06.014
    Abstract ( )   PDF (380KB) ( )   Save
    Under a new developmental idea,i.e.,sustainable development,the modern societal and economic development is moving step by step towards the orbit of harmonious development with eco environment.In this course,the research on eco environment carrying capacity is very impor tant.In order to quantificationally analyze eco environment carrying capacity,this paper developed a quantitative method under the guidance of sustainable development principle.The main content includes 3 parts:(1) to quantify the development quality of society,economy and eco environment al subsystem and establish the index system and Pattern Recognition Approach(PRA);(2) to iden tify the Sustainable Development Degree (SDD) and to quantify the development quality of the study area with it; and (3) to build eco environment carrying capacity analysis model.Under the prerequisite of maintaining a certain eco environmental quality,using the model to adjust population quantity and economic scale and make the "society economy eco environment" system have higher development quality.The corresponding population quantity and economic scale are the indicators of eco environment carrying capacity.In the case study,this model was applied to the Haihe Basin.Taking 1998 as the year of the Haihe Basin present situation, considering the south to north water transfer project,the eco environment rehabilitation project and the improvement of water use efficiency,6 kinds of scenario schemes were designed.Based on the above method,quantification analysis of the changes of eco environment carrying capacity was made.Research result shows to improve water supply ability through the south to north water transfer project and to improve water use efficiency by changing industrial structure constitute one of the basic ways to solve the water eco environmental crisis in the Haihe Basin.The present research will offer scientific basis at both national and local levels for the formulation of sustainable development policies and the determination of regional population and economic development scale that is suitable to local natural resource and environment situations.
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    Study on the parametric models and measures in welfare estimation of natural resources:Comparison of theory and application
    ZHAO Jun, YANG Kai
    2004, 19 (6):  795-803.  doi: 10.11849/zrzyxb.2004.06.015
    Abstract ( )   PDF (400KB) ( )   Save
    Estimating the social welfare produced by natural resources is one of the focuses in the field of resources and environmental economics.Contingent valuation method (CVM) is one of the most dominating techniques for the estimation.Although the parametric model based upon linear utility difference was preferred in the subsequent studies since 1984 when Hanemnn incorporated logit model into CVM,yet with the fast development of computer software,the problem is advanced that whether the logit model can well fit the natural resources demand curve and whether it is appropriate for the welfare measures used in the previous studies need to be clarified.We firstly deduced in details the parametric models and the corresponding welfare measures supported by the theory of random utility maximization,then in a case study the fitnessf good comparison between linear models and loglinear models based upon ad hoc utility difference was made.It is showed in this paper that:(1)Linear models such as logit advanced by Hanemann can well fit the Willingness to pay (WTP) curve and measure the welfare change of nalural resources,and the zero WTP can be adjusted by Spike model in linear models.Although there is no significant difference in the results such as mean WTP between linear and log linear models,yet this can not cover the possible truth that the significance level of linear models may be obviously lower than the log linear ones.(2)Log models based upon non linear utility difference can especially in the tails fit the WTP curve very well,which may be more appropriate for the description of the natural resources demand curve but not private goods.There is no significant difference between log logit and log probit models.(3)Median WTP is sensitive to the distribution assumption of consumer preference,and there exists difficulty in measuring the total social welfare because of the definition of the median.We suggest that the mean WTP calculated under log logit model should be used to measure the welfare change of natural resources in contingent valuation method,which can be got by numerical integration in the interval of from zero to the maximum bid amount.(4)Log linear models effectively excluded the negative WTP and make the models more powerful for the valuation program for resources protection or improvement project,but log models can not consider the zero WTP while the linear models can,and log models will bring obvious fat tail effect in the calculation of mean WTP,so more discussion and improvement are needed for the above flaws of log models.
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    An application of partial least-squares regression method to the study of land use patterns
    ZHANG Yang, ZHOU Chenghu, DAI Jinfang, MA Ronghua
    2004, 19 (6):  804-810.  doi: 10.11849/zrzyxb.2004.06.016
    Abstract ( )   PDF (280KB) ( )   Save
    Land use is the linkage between human and nature.It is subject to natural environment and is seriously influenced by social and economic activities.So the study on land use patterns and their influential factors has become indispensable in LUCC research.Heavy interaction of research data and inadequate observation samples are the key problems to this study.Thus it is very important to optimize the research methods. Partial Least Squares (PLS) regression is a novel multivariate data analysis method developed from practical applications in real world.It is mainly used to model linear regression between multi dependent variables and multi independent variables.PLS regression has many advantages, which traditional methods do not have,such as avoiding the harmful effects in modeling due to the multicollinearity and regressing when the number of observations is less than the number of variables,etc.Moreover,it can combine the basic functions of regressing model,principal compo nents analysis (PCA) and canonical correlation analysis.Therefore,PLS regression is a optimized tool to LUCC research. In this paper,PLS regression is applied to study the relationship between land use patterns and their influential factors,taking Suxichang region as a case study.Supported by SAS/STAT statistical software,the PLS regression model was built and the calculated results were meticulously analyzed.Though the accuracy analysis of PLS factors,the most important PLS factors were selected,used in studying the relationship between each type of land use pattern and its influential factors.In addition,a predict model about land use pattern change was produced and analyzed. This case study confirmed the practicability and operability of the PLS regression method.It showed that PLS regression has the ability to make quantitive research on land use patterns,and could be widely applied to geographical research.
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    Assessing the tourism value of tourism resources-A case study of Dunhuang
    GUO Jianying, WANG Naiang
    2004, 19 (6):  811-817.  doi: 10.11849/zrzyxb.2004.06.017
    Abstract ( )   PDF (288KB) ( )   Save
    The values of tourism resources include tourism value, scientific research value, his toric culture and education value,environmental value,option value,bequest value and existence value.Many researchers have done a lot of studies on assessing tourism resources' scales,quality, hierarchies,exploiting future and conditions as well.Only a few did some researches on evaluating the values of tourism resources.In fact,it is very important to estimate the values of tourism resources.In this article the author introduces a newly developed method,i.e.,Travel Cost Method. Then,the author designs a research route to assess the tourism value of tourism resources.At the same time,the author proposes a way to get the coefficients of multi destinations' travel and to define the opportunity cost of the recreational time.According to the investigative data on the spots,the tourism value of tourism resources of Dunhuang is evaluated by using expenditure method,travel cost method and opportunity cost method.It turns out that the tourism value of tourism resources of Dunhuang is RMB 789.61 million yuan.With the development of tourism,the number will change.
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    Study on spatialization technology of terrestrial eco-information in China(III): Temperature and precipitation
    LIU Xinan, YU Guirui, FAN Liaosheng, LI Zhengquan, HE Honglin, GUO Xuebing, REN Chuanyou
    2004, 19 (6):  818-825.  doi: 10.11849/zrzyxb.2004.06.018
    Abstract ( )   PDF (415KB) ( )   Save
    Applying three dimension second order trend surface analysis and spatial interpolation method,with the meteorological data in 1971~2000 of 722 stations in China,climatic factors such as temperature,precipitation, and air humidity have been spatialized on the ArcGIS platform, and produced 180 climatological thematic maps with a resolution of 1km2.The findings indicate that mean absolute errors of climatic factors are as follows:0.5℃ for mean temperature,mean maximum and minimum temperature;1℃ for extreme maximum temperature;1.5℃ for extreme minimum temperature;and 0.4 m·min-1 for mean wind speed.The mean relative error of some factors: accumulated temperature of ≥0℃,5℃,10℃,15℃, mean relative humidity is below 5%, and precipitation and water vapor deficit is about 10%.In conclusion,the simulated results of models are basically up to the level of application requirements.It provides basic data and a research platform for the disciplines of ecology,geography,and resources & environmental science.Analyses show that the spatial temporal pattern of spatializaiton error of climatic data varies with the density of meteorological observation stations and the characteristic of meteorological factor,etc.,in a general trend of western region > eastern region,winter > summer,discrete climatic factor > continuous ones,the extreme value > the mean value.
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