Table of Content

    20 January 2007, Volume 27 Issue 1 Previous Issue    Next Issue
    Prospects of Urban Agglomeration in the Changjiang (Yangtze) River Delta
    GU Chao-Lin, ZHANG Min, ZHANG Cheng, ZHANG Xiao-Ming, WANG Chun, CHEN Lu
    2007, 27 (1):  1-8.  doi: 10.13249/j.cnki.sgs.2007.01.1
    Abstract ( 140 )   PDF (1047KB) ( 21 )   Save
    China is facing a large unprecedented social revolution,in which the development of economy and society promotes the rapid urbanization process.The urban agglomeration in the Changjiang(Yangtze) River Delta is the largest one in China,whose development and evolvement play an important role in the development of Chinese cities and economy in littoral areas of China,even in the development of Asia-Pacific Region.Since reform and opening-up took place in China,the rapid development of Chinese economy and the accelerating of economic globalization have provided the crucial opportunities and challenge for the development of urban agglomeration in the Changjian River Delta.This paper focus on the prospects of urban agglomeration in the Changjiang River Delta.
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    Study on Urban Economic Vatality Index in China
    JIN Yan-Jie
    2007, 27 (1):  9-16.  doi: 10.13249/j.cnki.sgs.2007.01.9
    Abstract ( 179 )   PDF (940KB) ( 29 )   Save
    Economic competition usually takes place on levels of country,industry and enterprise.With the economic globalization,cities have been the main body of competition.In China,economic total amount and developmental rate play an important role in evaluation of urban economic activity which roots in enterprises(mostly the nongovernmental business),foreign trade and capital.The income level of local residents decides the attraction to labor force which is the endogenetic energy of economic activity.Finance and social security system are perceived as important guarantees for urban development.The level of technology and education is becoming an important source of the increase of economy. Environment which correlates the sustainable development is placed high value on as an external factor of economic development.This paper uses factor analysis method to evaluate 50 cities in China from aspects of economy and its growth,amount and income of enterprises,income of residents,finance and social security,foreign trade and capital,level of technology and education,and environment. Urban benefits and production are main factors of the economic vitality.The 50 cities are classified as five levels by scores.The most developed cities lie in the Changjiang(Yangtze) River Delta Area and Zhujiang(Pearl) River Delta.Shanghai and Shenzhen which play the important role in the areas belong to the first level.The gap between coastal cities and inland ones is still large.
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    Index System and Method of Residential Environmental Evaluation in Inner Cities
    ZHANG Wen-Zhong
    2007, 27 (1):  17-23.  doi: 10.13249/j.cnki.sgs.2007.01.17
    Abstract ( 216 )   PDF (1073KB) ( 38 )   Save
    Recently,governments have paid attention to a Livable City as well as researchers and the media in China so that a Livable City has become a new focus in Chinese urban development,but they mostly focus on the concept of a Livable City and few could turn ideas into action.The paper points out that we should make the intrinsic meaning of a Livable City clear and confirm the definitions of Livability and a Livable City and principles of a Livable City,and then establish and quantify its index system.Through the evaluation of a Livable City,we would find the strength and weakness of the city as a Livable City,which would be helpful to confirm its construction orientation and developmental steps in the future.Based on relevant research literatures of theory about a Livable City and practice of urban construction and the concept of "a city for people",the paper systematically does research on evaluative content of a Livable City,index system design and evaluative methods of residential environment in inner cities.Firstly,The paper sets up the evaluative framework of a Livable City focusing on appraising 5 indexes such as convenience,amenity,health,safety and community of a city,which includes two index systems,that is,the index system of objective evaluation including 5 index and 21 sub-indexes and the index system of subjective evaluation including 5 index systems and 31 sub-indexes.Secondly,the paper discusses how to gather data.On the one hand,the objective data should be got from digital map,SPOT data,GIS data and so on.On the other hand,the subjective data should mainly gather resident survey data and fieldwork.Finally,the paper presents three main evaluative method systems such as Economical Value Evaluation,GIS tools and econometric estimation.Economical Value Evaluation,aiming to assess the value of residential environment adjustment and value difference of residential environment,includes Contingent Valuation Method,Direct Expenditure Method,Consumer’s Surplus Method,Travel Cost Method,Hedonic Price Method,Contingent Valuation Method and Computable General Equilibrium.Furthermore,the paper establishes a framework of residential environmental evaluation based on GIS to quantify different spatial levels of residential environment in inner cities and put evaluative results into maps directly, and then it would also analyze effecting factors,spatial differences and spatial structure of a city as a Livable City by multidimensional scaling,factor analysis,cluster analysis and multiple regression analysis.According to the evaluative results,we can prospect the trends in the determinants of livability and spatial trends in livability across areas,and give suggestions for the development of a Livable City such as that of determinants of livability,policy suggestions of infrastructure construction by different population groups and that of regional development in a Livable City.
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    Development of Light Rail Transit with Medium Freight Volume in Metropolitan Region of China
    YUAN Jia-Dong, YU Ning
    2007, 27 (1):  24-30.  doi: 10.13249/j.cnki.sgs.2007.01.24
    Abstract ( 180 )   PDF (732KB) ( 5 )   Save
    With the high-speed development of national economy,China’s urbanization has taken a fast-progessing track.In some relatively highly developed areas,dramatic changes have taken place in the spacial structure of big cities.The most notable characteristic is the transition from the simple form of a single city to a most complicated structure of metropolis,which is based on the core city surrounding by numerous cities and regions.The four metropolitan areas such as SH,BJ,GZ and SY have formed the preliminary shape,meanwhile,in the surrounding areas of those big and medium-sized cities with relatively high development economy and society,some regional metropolises and local metropolises are taking shapes as well.The formation and development of these metropolises has a very important supporting role to the social development of our regional economy.There is a consensus in adopting the metropolitan development strategy with an unbalanced growing pattern so as to promote the social development of our regional economy.However,the buildup of metropolises is confronted with many problems in the area of environment,land resources,transportation,energy and industries.Transportation is the most prominent issue among all these problems.The construction of a modern transportation system in the metropolis is most significant in terms of enhancing the connection of core city and surrounding towns and areas,helping the integration of land use in cities within the metropolis,boosting the joint construction and use of cross-region infrastructure;protecting and utilizing all kinds of resources,improving the living and investing environment and realizing the integration of metropolis.But the construction of the transportation system in the metropolis development strategy is sometimes accompanied by blindness.This article starts with analysis of the spacial structure and transportation requirements in the metropolis and discusses about the role and function of light rail transit with medium freight volume in public transportation.Taking into account of the issues in the development of light rail public transportation,the author makes a point that the development of public transportation with light rail transit with medium freight volume as the backbone is an important approach in the metropolis,provides many suggestions for the planning of comprehensive transportation system based on the light rail transit with medium freight volume in a metropolis.
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    Development of urban CBD system in Xi’an: Characters and Tendency
    WANG Hui, TIAN Ping-Ping, LIU Hong, QIN Si-Gang
    2007, 27 (1):  31-39.  doi: 10.13249/j.cnki.sgs.2007.01.31
    Abstract ( 124 )   PDF (2120KB) ( 17 )   Save
    Chinese cities have been experiencing remarkable restructuring in the reform and opening-up.The transformation of the existing urban central areas and the development of urban CBD systems have become a rather important part of the restructuring of Chinese cities since the 1990s with the introduction of the mechanism of land market,the rapid development of the tertiary industry,as well as the change of cities’ master plans.Based on the latest data from a variety of sources,such as the land leasing and transferring,the development of commercial office-buildings and shopping centers,the digital database of ’the 2nd National Census of Basic Economic Units in China’ and so on,using the basic theories on the contemporary CBD development in Western cities for reference,taking the city of Xi’an as a case,the dynamics,characters,tendency,and the relevant mechanisms of the development and evolution of the CBD system in contemporary urban China are analyzed in this paper.The results indicate that: a) the city’ old central area has been experiencing a functional ’purification’ characterized by the reduction of the total contained functions and the intensification of the commercial(especially retail) activities,which are resulted from the out-moving of manufactories,population,administration departments,and some producer services;b) the ’business centers’,i.e.the concentrated area of producer services,have been obviously ’floating’ outwards from the old central area,but the locations of the ’commercial centers’,indicated by the concentrated area of retail,are still relatively steady,as a result,the city’s CBD(central business district) and CRD(central retail district) are spatially separating from each other;c) the city’s new Hi-Tech Industrial Development Zone(i.e.the state-level Xi’an HTDZ) has been playing a increasingly significant role in the development of the city’s CBD system and is growing into the actual new CBD of the whole metropolitan area of Xi’an because of the comparatively more favorable conditions in many aspects in it for the clustering and development of the producer business services;d) the city’s CBD system is tending to evolve into a ’bi-pole,multi-core’ pattern,in which the two ’poles’ refer to the separated CRD(still staying in the city’s old central area) and CBD(coming into being in the HTDZ),and the multiple ’cores’ refer to another four existing or upcoming business centers located in the city’s another two new development zones,i.e.Xi’an Economic & Technological Development Zone,and Xi’an Qujiang Tourism & Holiday Resort Zone,as well as the central sector of the city’s ’university belt’,i.e.the most concentrated area of universities and research institutions,respectively.
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    Driving Mechanism of Land Use/Coverage Change in Southern Laizhou Bay
    ZHANG Zu-Lu, WANG Lin
    2007, 27 (1):  40-44.  doi: 10.13249/j.cnki.sgs.2007.01.40
    Abstract ( 141 )   PDF (618KB) ( 13 )   Save
    Being the most seriously infected area by salt water intrusion in China,southern Laizhou Bay has a more complicated land use/coverage change and driving mechanism.In order to extract the main driving factors,the author practiced the classic correlation analysis.So in socioeconomic aspect,population increase,industry structure adjustment,and the development of industry and urbanization are summarized.In natural condition,the salt water intrusion is pinpointed,which has an accordant process with the trend of land use structure change.Each factor is dwelled on separately.
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    Land Use/Cover Dynamic Changes in the Northern China
    LI Yue-Chen, LIU Chun-Xia
    2007, 27 (1):  45-52.  doi: 10.13249/j.cnki.sgs.2007.01.45
    Abstract ( 161 )   PDF (961KB) ( 15 )   Save
    The eco-environment of the 13 provinces in the northern China is relatively fragile.In order to understand the eco-environment feedback mechanism and seek a way to optimize land use/cover spatial pattern under ecological security,land use/cover dynamic changes in the northern China from 1989 to 1999 was investigated by RS and GIS.The results show that:(1) Grassland,unused land and forestland were the main land use/cover types in the research areas.In the study period,land use/cover change greatly.Although the eco-environment policies of government resulted in some original farmland being returned to grassland and forestland,the excessive reclamation in the region turned more grassland and forestland into farmland simultaneously.(2) Human activities comprehensively affected land use/cover dynamic change in the study area.The heterogeneity of the whole landscape increased.The land use/cover spatial structure tended to be more diversified and even.(3) The center of gravity of all land use/cover types changed.The water body is the most distinct and unused land,farmland and urban land follow.(4) Land use/cover changes show regional district differences.
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    Simulation on Relations between Land Use Type and Land Productivity in Loess Hilly Region—A case study in Wangjiagou catchment
    LI Zhong-Wu, CAI Qiang-Guo, ZENG Guang-Ming
    2007, 27 (1):  53-57.  doi: 10.13249/j.cnki.sgs.2007.01.53
    Abstract ( 136 )   PDF (582KB) ( 21 )   Save
    The land use type is a pivotal factor affecting land productivity in loess hilly region.Using the land productivity model based on erosion,supported by geographic information system(GIS),the paper researched the relation between different land use types and land productivity of hilly loess region.The result showed,to a majority of crops,land productivity of different land use types has a law,namely,bottomland >terrace >slope land>gully wall.In order to research the mechanism further,the paper discussed adaptability index and productivity index of different kinds of crop for different land use types,which embodied the same trends.
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    Scaling Character of Spatial Structure of Land Use
    ZHU Xiao-Hua, LI Jia-Lin, YANG Xiu-Chun, CAI Yun-Long
    2007, 27 (1):  58-62.  doi: 10.13249/j.cnki.sgs.2007.01.58
    Abstract ( 154 )   PDF (883KB) ( 16 )   Save
    In this paper,the fractal theory,multivariate regression analysis and grey relational analysis are applied to analyzing the spatial fractal character and its scale character of land use as a case study of Cixi City and Guizhou Province with scale of 1:100 000 and 1:1 000 000 respectively. The perimeter-area relationships of patches of different land types of Cixi City and Guizhou Province under different scales are established;the fractal dimensions of spatial structure of different scale regions of China are calculated.The fractal characters of land use structure in Cixi City and Guizhou Province are analysed,the relationships between fractal dimension of land spatial structure and patch number,average patch area and average patch shape index are established by multivariate regression analysis.It is indicated that patch number,average patch area and average patch shape index mainly influence the fractal dimension of spatial structure of land use,and the spatial fractal character of land use exists over scale.Based on the grey relational analysis,it is further found that patch number is the most important factor that influences the land fractal structure of Guizhou Province,and average patch shape index for Cixi City.Although the land spatial fractal structures of Cixi City and Guizhou Province are mainly influenced by the geometric characteristic of spatial pattern of land use.
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    Diurnal Variation of Surface Albedo and Relationship between Surface Albedo and Meteorological Factors on the Western Qinghai-Tibet Plateau
    LI Guo-Ping, XIAO Jie
    2007, 27 (1):  63-67.  doi: 10.13249/j.cnki.sgs.2007.01.63
    Abstract ( 155 )   PDF (435KB) ( 40 )   Save
    By using the continuous observational data of air,radiation and soil from two sites of automatic weather station(AWS) at Gaize and Shiquanhe on the western Qinghai-Tibet Plateau in the period from October 1997 to November 1998,the diurnal variations of surface albedo in summer and winter are analyzed.Furthermore,the stress of this paper is put on discussing the relationship between surface albedo and some meteorological factors(such as soil moisture,surface moisture temperature,air relative humidity and air temperature).The results are helpful to improve the parameterization schemes of surface albedo in climate model and satellite remote sensing.
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    Causes,South Borderline and Subareas of Permafrost in Da Hinggan Mountains and Xiao Hinggan Mountains
    SUN Guang-You, YU Shao-Peng, WANG Hai-Xia
    2007, 27 (1):  68-74.  doi: 10.13249/j.cnki.sgs.2007.01.68
    Abstract ( 271 )   PDF (1521KB) ( 40 )   Save
    Based on other scholars’ research,the paper establishes a new distributing pattern of permafrost in the Da Hinggan Mountains and Xiao Hinggan Mountains.It has made important progress in the formation causes and distribution pattern of the permafrost,but the conclusion that the permafrost was engendered mainly by latitudinal zonality,which was a part of Eurasian permafrost zone,should be discussed.The paper considers vertical zonality the dominant action in the formation of the permafrost. The elevation of the Da Hinggan Mountains and Xiao Hinggan Mountains heighten gradually from north to south.The descending temperature coming from elevation rising compensated the ascending temperature coming from low latitude relatively.The result made the types and subarea borderline protrude to south enormously.Taking the Da Hinggan Mountains as a whole,it was not feasible to take the south as mountain permafrost only.So,the south permafrost borderline of the Da Hinggan Mountains was in the south of Huanggangliang Mount and also 120 km south to Aer Mount.The south permafrost borderline of the Xiao Hinggan Mountains was in the south of middle mount nearby the Hulan River.The sheet permafrost subarea in the north of the Da Hinggan Mountains should include the region with an elevation of about 1000 m of Yilehuli Mount.That was to say,the east borderline of it was 70 km east to Xinlin.The insular thawy region of permafrost subarea in the Da Hinggan Mountains extend from middle chine of Yilehuli Mount to Aer Mount.And there were closed loops of insular thawy permafrost in middle mountains nearby the Wangtang River and the Hulan River in the south of the Xiao Hinggan Mountains.
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    Timing and Structure of Glacial Climate Events Derived from an Annually-Growth Stalagmite δ18O Record from Hulu Cave,Nanjing
    WU Jiang-Ying, SHAO Xiao-Hua, WANG Yong-Jin
    2007, 27 (1):  75-80.  doi: 10.13249/j.cnki.sgs.2007.01.75
    Abstract ( 134 )   PDF (604KB) ( 26 )   Save
    Greenland ice cores provided the most directly and highly resolved records of glacial climate events during the past 120 000 years,but they presented different time scales for these rapid climate events.As we previously reported,precisely-dated and high-resolution cave δ18O records make it possible to correct the chronologies of Greenland ice cores.Furthermore,annual to decadal-resolved monsoon records would explore a detailed transition pattern for the climate events,providing a crucial test for physical models of abrupt climate events.Here we present such precisely-dated East Asian monsoon record between 24 and 21 ka B.P.,and then discuss a possible forcing mechanism for the climate events during the Last Glacial Maximum.The growth phase for one stalagmite from Hulu Cave,Nanjing,has been precisely dated by thermal ionization mass spectrometry and counting result for continuous annual lamination profile under microscope.A total of 727 sub-samples were scraped off from successive laminations of the polished column and their oxygen isotope composition was measured by MAT-253 mass spectrometry.Based on the 230Th dates and more than 3000-year-long duration of annual banding sequence,an average 3-year resolution stalagmite δ18O time series between 24 and 21 ka B.P.has been established.The high resolution oxygen isotope record well reflects the variation of Asian summer monsoon precipitation during the last glacial period,i.e.the more negative value of stalagmite δ18O,the higher precipitation.The stalagmite δ18O record displays large amplitude from-4.709‰ to-8.709‰ in δ18O value,suggesting that monsoon precipitation changed largely in magnitude even during the Last Glacial Maximum.We recognizes two cycles of wet/dry from this record: one is from 24.0 to 22.1 ka B.P.and the other is from 22.1 to 21.1 ka B.P.Most importantly,shorter-term climatic events are superimposed on the two millennial cycles,coherently linking to the remote climate events,such as Heinrich events in North Atlantic and Dansgaard-Oeschger events in Greenland ice core records. The precisely-dated δ18O record provided a strong support for accuracy of the GISP2 time scale.An IS2 event(or DO 2),well expressed in the Greenland ice core δ18O records,can be unambiguously identified in our record.The timing of IS2 in GISP2 is close to the chronology of the stalagmite records within the uncertainty of U/Th dates.However,GRIP and NGRIP are younger than GISP2 by 800 to 2000 years for the same event.This discrepancy among the three Greenland ice cores would come from a larger uncertainty for the ice cores: age errors up to 1% during the Holocene and the uncertainties become larger as the chronology gets older.If the time scale of GISP2 is accurate before 40 ka B.P.based on ice-layer counting,we suggest that the event was synchronous over the Northern Hemisphere. Our record,in combination with the previously-published record between 17 and 15 ka B.P.also from Hulu Cave,indicated that the monsoon events(H1 and H2),in terms of their structures,are quite different from the cold events in North Atlantic,which were well presented in the Greenland ice core δ18O records. For the both of H1 and H2,the monsoon precipitation records show a rapid transition from dry to wet conditions,followed by a stepwise increasing trend,with a total duration of more than 600 years.In contrast,the Greenland δ18O records display abrupt changes either into or out of the events.This suggests that changes of East Asian monsoon were triggered by not only the North Atlantic themorhaline circulation but also the coupled oceanic-atmospheric circulation from tropical Pacific.
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    Sedimentary Records of Paleoflood Events During the Last 3000 Years in Jianghan Plain
    XIE Yuan-Yun, LI Chang-An, WANG Qiu-Liang, YIN Hong-Fu
    2007, 27 (1):  81-84.  doi: 10.13249/j.cnki.sgs.2007.01.81
    Abstract ( 92 )   PDF (566KB) ( 12 )   Save
    It is well known that paleoflood predictions must depend on its occurrence rule.However,available historical records do not provide long enough temporal scale for identification of emergence law of flood events.It is very important and necessary to discover and understand floodwater geological records.The pluvial geological records of Jiangling area in Jianghan Plain,show that the area revealed 18 flood events during the last 3000 years.The paleoflood events corresponded to cold and wet climate.With the help of power spectral analysis,it is found that paleoflood events include 26,31,36,43,52,79,110 a cycles.It is indicated that solar activity may be driving factor of paleoflood in Jiangling area.
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    Variation of River System in Center District of Shanghai and Its Impact Factors During the Last One Hundred Years
    CHENG Jiang, YANG Kai, ZHAO Jun, YUAN Wen, WU Jian-Ping
    2007, 27 (1):  85-91.  doi: 10.13249/j.cnki.sgs.2007.01.85
    Abstract ( 159 )   PDF (487KB) ( 39 )   Save
    Based on the data of disappeared rivers from 1860 to 2003 in center district of Shanghai,the variation of river system and its environmental impact were analyzed.The research results showed that:(1) Over 260 rivers,with a length about 470 km disappeared in center district of Shanghai during the past 140 years.The water area and water surface ratio reduced 9.42 km2 and 3.25%,respectively.The structure of river system was destroyed greatly.High-urbanization lessened the branching ratio,which leaded to an abnormal fractal dimension.(2) The rivers in the center district centralizedly disappeared during several phases.The reasons for river disappenring were altered in different times.From 1860 to 1949,the reasons included roads building,natural oblivion,concession expansion and residence zone building.From 1949 to 2003,those were city planning construction and residence zone building.(3) At a rough estimate,from 1860 to 2003,the substantive disappeared rivers caused the total river storage capacity and per area river storage capacity reduce about 20.92?106m3 and 50.6?103m3/km2,respectively.Now,the total river storage capacity reduced near 80% compare with that of 140 years ago,so the ability of storage capacity was greatly weakened in the center district of Shanghai.The number of cumulative built municipal pumping stations was significantly positively related with cumulative number,cumulative length and cumulative storage capacity of disappeared rivers from the 1950s to the 1990s.
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    Extraction of Chlorophyll-a Concentration Based on Spectral Unmixing Model in Taihu Lake Water
    WEN Jian-Guang, XIAO Qing, LIU Qin-Huo, ZHOU Yi
    2007, 27 (1):  92-97.  doi: 10.13249/j.cnki.sgs.2007.01.92
    Abstract ( 166 )   PDF (491KB) ( 17 )   Save
    Thematic Mapper(TM) data can be used to estimate chlorophyll-a concentration of water body and monitor the quality of inland water.There are different models for TM estimating Chlorophyll-a concentration,and the major model is empirical regression model.In this paper we build chlorophyll-a models based on TM data,in which the traditional band ratio approach and mixing spectral analysis model were used.And we also analyzed the method of end-member extraction.The correlation coefficient and rooted mean square errors were calculated,and the results of chlorophyll-a concentration gained from these models and those gained from the analysis in lab were compared,the result shows that the mixing spectral model for estimating Chlorophyll-a concentration is a optimal method.
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    Seasonal Change of Soil Moisture Content in Dried Soil Layer in Artificial Forest in Gaoling of Xi’an
    DU Juan, ZHAO Jing-Bo
    2007, 27 (1):  98-103.  doi: 10.13249/j.cnki.sgs.2007.01.98
    Abstract ( 172 )   PDF (256KB) ( 23 )   Save
    Through field investigation and indoor determination,by the method of drying and weighing,the soil moisture content in the layer of 06m and seasonal change of soil moisture content in artificial forest before and after abundant water year in Gaoling of Xi’an were studied in this paper.The results show that there were all dried soil layers in the 160400cm layer below Chinese parasol trees and poplar trees in 2002.In 2004,from 0 to 6m the dried soil layer has not appeared below the apricot and Chinese scholartrees,which proved that the soil moisture has resumed completely in abundant water year of 2003.After the abundant water year soil moisture content in 160-400cm and 410-600cm below pear,the apricot,Chinese scholartrees all are highest in spring,next is in summer,it is lowest or rises slightly in autunm.
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    Wind-protecting Effect of Shrub Dunes in Ecotone of Minqin Oasis
    WANG Sheng-Tang, ZOU Xue-Yong, CHANG Chun-Lai, CHENG Hong
    2007, 27 (1):  104-108.  doi: 10.13249/j.cnki.sgs.2007.01.104
    Abstract ( 199 )   PDF (698KB) ( 39 )   Save
    The belt of oasis border is usually called as ecotone of desert and oasis,which is mainly composed of shrub dunes.These shrub dunes can be divided into stable dune,semi-stable dune,semi-shift dune and shift dune by coverage of vegetation.A lot of studies have indicated that these shrub dunes are nature roughness unit and they have significant roles on airflow near land surface.They can change airflow structure and interchange of air torrent at boundary layer near land surface.They can also increase resistance of land surface to moving airflow by enhancing aerodynamic roughness length.When airflow blow passed shrub dunes,wind speed will be decreased remarkably because the dunes resist wind.So,shrub dunes in ecotone are very important defending barrier to nature oasis.This research selected a sample line(965m) mainly composed of stable dune,semi-stable dune and semi-shift dune in ecotone of Minqing oasis and one of stable shrub dune as study object.Field observation results indicate that mean wind speed at layers near land surface decrease 4.4% through the sample stable shrub dune and decrease 57% through the sample line.The mean wind velocity is reduced continuously along the sample line.At the edge of cropland inner of oasis,the wind velocity is only 21% referring to reference observation point. But shrub dunes in ecotone of oasis are one kind of the most vulnerable and unstable ecosystem and they are easily vulnerable to become degeneration ecosystem so as to threaten the sustainable development of oasis.The evolutions of shrub dunes are mainly influenced by human activities and climate changes.If they degenerate to be shift dunes,they will change from shelter barrier to be dust bowl.So,attention should be paid not only to the inner but also to the outer of oasis about its protection.Shrub and grass belts should be built in the surroundings while windbreak grid built in the inner and base windbreak built at the edge of oasis.Water is the most important factor to the stableness of the ecotone.It is significant for the sustainable development of oasis to supply sufficient ecological water utilized to realize the stableness of the belts of oasis border,at the same time,all kinds of human destruction activities should be forbidden.
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    Quantitative Analysis for Classification of Geomorphological Types
    GAO Xuan-Yu
    2007, 27 (1):  109-114.  doi: 10.13249/j.cnki.sgs.2007.01.109
    Abstract ( 261 )   PDF (806KB) ( 37 )   Save
    For decades,people have studied geomorphological classification in different ways and from different perspectives,and much progress has been made and each scheme has played a role in the development of geomorphology.In recent years,a statistical method has used to study geomorphology widely.This study empirically shows that it is also possible to classify geomorphological forms using mathematic method.It is different from the traditional method of classification.The main principle of quantitative analysis is to consider all factors synthetically,contrast all the data of each sample and make a classification grade according to the degree of similarity.The most similar and smallest geomorphological unit is taken into the first degree,the next most similar and small geomorphologic unit into next degree,the more different and bigger geomorphologic units into next and next degrees.We continue to proceed in this manner until we can classify the whole area’s geomorphological forms. This paper considers computer based quantitative analysis as a means to classify the geomorphological forms of Liangcheng County.It discusses a quantitative method of classifying geomorphological forms.As with the introduction of any new method to a subject,there are a number of technical challenges to be solved. Here we make a thorough investigation of problems such as how to measure and obtain data,how to select the basic sample units,how to determine the sample boundary lines,the optimum number of samples to take,etc.using quantitativeing analysis to classify geomorphologic forms,which has advantages over traditional classification in three aspects: detail,quantification and synthesis.
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    Comparison of Two Statistical Models in Contingent Valuation Method
    LI Hua-Sheng, XU Hui, PENG Bu-Zhuo
    2007, 27 (1):  115-120.  doi: 10.13249/j.cnki.sgs.2007.01.115
    Abstract ( 148 )   PDF (743KB) ( 25 )   Save
    Although the Contingent Valuation Method(CVM) is considered as an only method to evaluate the non-use value of biodiversity and other environmental resources by scholars abroad and at home,there still exist some undefinite factors such as the accuracy and availability of the valuing outcome and various error etc.To improve the accuracy and availability of the outcome of the method,the authors raise another statistical model,i.e.,stratified random sampling model,and compare it with simple random sampling model which is usually used.The case study was chosen in Yaoluoping National Nature Reserve which preserves plants and animals of sub-tropical zone in China.On the basis of the statistic data of questionaire in Jiangsu and Anhui provinces,the two statistical models are applied and compared in this paper.The mean WTP(willingness to pay) of Anhui and Jiangsu procince is 14.2 yuan(RMB) and 42 yuan acoording to the outcome of the questionaire.The mean WTP of the simple random sampling method is 47.8 yuan per person while that of stratified random sampling method is 28.6 yuan per person,so the total WTP of the two methods is 331 335?106 yuan/a and 198 039 million yuan/a respectively.The result indicates that the outcome of the stratified random sampling method is 60% of that of the simple random sampling method,and the former can improve the accuracy and availability of the outcome comparing with that of simple random sampling method to some degree.The authors show that the stratified random sampling method is an alternative approach though it has some deficiencies initiated from CVM method itself.
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    Application of Multilevel Grey Evaluation in Tourist Perception
    WANG Xia, GU Chao-Lin, MEI Hu
    2007, 27 (1):  121-126.  doi: 10.13249/j.cnki.sgs.2007.01.121
    Abstract ( 148 )   PDF (799KB) ( 14 )   Save
    Tourist perception is a psychological process through which tourist obtains information on travel target,environment of tourist destination.The evaluation of tourist perception involves a lot of factors,and the appraising information is not complete and exact entirely,which determines the gray nature of the evaluation system.Direct to this characteristic,this article makes the comprehensive evaluation of tourist perception by way of combining the AHP(Analytic Hierarchy Process) and Grey Theory.First,key factors that influence tourist perception are analyzed and the evaluation index system of tourist perception is then set up.Second,the weights of each index are obtained through AHP method.Finally,taking the five main tourism destinations in the Mega-Guilin Tourism Circle for examples,this article applies the method into the evaluation process.The empirical study shows that the result of the multilevel grey evaluation of tourist perception is objective and reliable.It can offer reference for the decision-making of planning,management and marketing of tourist destination.
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