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Issue No.4

General Review on Effects of Soil and Water Conservation
Measures on Water Resources in China

LI Zijun1, ZHOU Peixiang2, MAO Lihua3
(1.Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China;
2. Shandong Jian Zhu University, Jinan 250101, China; 3. Jinan University, Jinan 250002, China)

Abstract: In recent years, with more and more officials and professionals paying attention to the problems such as soil erosion and water loss, the exquisite contradiction between water supply and demand, whether soil and water conservation measures on upper regions would have effect on the amount of water resources of the lower reaches is a scientific issue to be discussed and probed into urgently. Primary achievements of effects of individual soil and water conservation measures on water resources as well as benefits of runoff reduction of watershed management in China have been reviewed and analyzed synthetically on the runoff plots scale and whole watershed scale respectively, and the benefits of runoff reduction of some large watershed have been analyzed and compared with each other . Some existing problems in this research field at present have been expounded and prospect is put forward at last.

Key words: soil and water conservation measures; water resources; benefits of runoff
reduction

The Externality of Beijing’s Traffic Issues and
It’s Government Solutions

XU Guangqing
（School of Environment and Natural Resources, Renmin University of China, Beijing, China, 100872）

Abstract: By Aug. 2003, there were more than 2 million motor cars, including 1.3 million owned by privates. As population expand incomes increase, and car prices go down, more cars will be seen in streets of Beijing. Beijing’s traffic congestion causes many social and natural problems, such as air pollution and deaths in traffic. We recommend using the externality theory of environmental economics to understand the externalities of car transportation. The crux of Beijing’s traffic congestion is the market failure caused by its externalities. Because of the group characteristic of the car transportation, the handling of its externalities should be relied on government solutions. By looking into other cities’ traffic measures, such as London of UK, Singapore and Nagoya of Japan, we recommend using the combination of force control and economic incentive to reinforce the management of Beijing’s traffic, so as to control the total amount of cars, to limit too many cars to go into the center of the city in rush hours and to encourage the citizens to use the mass transportations. Limited certificate of car ownership, congestion charging, and encourgement system for using mass traffic tools might be considered to apply in Beijing.

Key words: traffic; externality; market failure; government solutions

Spatio-temporal Analysis of Regional
Internet Development in China

LIU Guifang
(China-Australia Cooperative Research Institute for Geographic Information Analysis and Applications,
Henan University, Kaifeng 475004, China)

Abstract: The rapid increase in economy and high-speed development in information industry have made Internet in China grow quickly. Meanwhile, the social informationization step has accelerated and regional information disparities have emerged. Combining the number of domains in each province with maps, this paper discusses these disparities in China spatially and temporally. Meanwhile, we improve some methods of correlation analysis, Lorenz Curve and location quotient et al., which are different to the traditional economic ones such as GDP. The conclusions are as the following: (1) The Internet development in China declines gradually from Eastern China to Western China. (2) The gap between high level provinces and low level ones was big. For example, in 2001, domains in Beijing were 442 times as much as those in Qinghai province. (3) Although the absolute disparities between Eastern China and Central China as well as Western China were widened from 1999 to 2005, the comparative disparities in each province were constant by and large. (4) This paper classified provinces into five categories using location quotient, which represents the difference with the average level. The classification distribution showed that the Internet development in Eastern China was increasing, in contrast to the stagnation in Central China and Western China. So, the development in Central China and Western China should be paid much attention to by the government. (5) The spatial distribution of domains was consistent with that of provincial GDP, but not accordant absolutely.

Key words： internet in China; regional difference; spatio-temporal analysis

Discussion of Spatial Linkage of Freight Transportation
by Highway in Provincial Region
——Taking Liaoning Province as an Example

ZHANG Jiansong1, HAN Zenglin2, DONG Xiaofei2
(1. Dalian Nationalities University, College of Economics and Management, Dalian 116600 )
(2. Liaoning Normal University, College of City and Environment, Dalian 116029)

Abstract: This paper uses economic geography analytical methods and basic theories of the traffic geography, regards Liaoning Province and affiliated 14 cities as the research object, analyzes in depth the characteristics of formation, growth, distribution and exchange of the highway freight transportation in Liaoning Province. “Hub-and-Spoke” network originated from airplane transportation. In this paper it is applied to road freight transportation network, and this is a creation. “Hub-and-Spoke ” network has already become the basic mode of highway freight transportation network in provincial region, and it embodies "Dual-nuclei" structure characteristic at the same time. This text divides highway freight transportation network of Liaoning Province into two systems of Shenyang-Dalian and west of Liaoning. In conclusion, the industrialization and transportation linkage of Liaoning Province enters middle and later periods, and the regional concentrations index of the traffic volume of the goods is high relatively. There are following characteristic in the highway freight transportation spatial linkage in the provincial region: there is one or several central cities, the volume of goods transported is decided by the nature of the city to a great extent, goods transportation is not closely related to the distance, and coastal port exerts a tremendous influence on the spatial linkage and so on.

Key words: highway; freight transportation; spatial linkage; Liaoning

Progress on Climate-Vegetation Modeling in the Tibetan Plateau

ZHAO Dongsheng1,2, LI Shuangcheng3, WU Shaohong1
(1. Institute of Geographic Sciences and Natural Resource Research, CAS, Beijing, 100101, China;
2. Graduate School of the Chinese Academy of Science, Beijing 100049, China;
3. College of Environmental Sciences, Peking University, Beijing, 100871, China)

Abstract: Modeling is a key method in the study of climate-vegetation， which is an important content in the field of global change researches. As a huge geographical unit, the Tibetan Plateau has strong effects on Chinese and East Asian climate because of its unique location and higher elevation. Because of special environment, the biomes on the Tibetan Plateau have many distinguishing characteristics that are not shown by some global models. The above-mentioned characteristics and less human disturbance make it an important area for study on climate-vegetation. This paper reviews five major types of climate-vegetation models that have been widely used to simulate response of vegetation to climate change and points out its advantage and disadvantage. Combining some related researches on the Tibetan Plateau, the paper summarizes the progress of climate-vegetation modeling from two aspects of vegetation distribution and vegetation net primary productivity, and finds modeling is a very important way for climate-vegetation researches. Nevertheless, in fact, climate-vegetation modeling is lagged behind other areas. So the crux of works in future is to master the crucial theories of climate-vegetation mutual reaction, then develop pertinent models with characteristics of the Tibetan Plateau.
Key words: the Tibetan Plateau; climate-vegetation; modeling

Review on the Approaches of Separating Autotrophic and
Heterotrophic Components of Soil Respiration

JIN Zhao1,2, DONG Yunshe1, QI Yuchun1
(1. Institute of Geographical Science and Natural Resources Research, CAS, Beijing 100101, China;
2. Graduate School of Chinese Academic Science, Beijing 100039)

Abstract: Soil respiration is an important part of global carbon cycle, which accounts for about 25% of the global carbon dioxide exchange. Estimating the contribution of soil organic material ( SOM-derived ) respiration, root respiration and rhizomicrobial respiration to total soil CO2 efflux and the carbon distribution between actual root respiration and rhizodeposits is crucial in determining the carbon and energy balance of plant and soil. Up to date a large amount of the researches have been done on partitioning total soil respiration into autotrophic and heterotrphic components and great progress has been achieved. But it is still very difficult to discriminate between the CO2 directly derived from actual root respiration and that derived from mineralization of rhizodeposits, and this has presented one of the greatest challenges to quantifying rhizosphere C-flow. Several methods have been suggested to separate SOM-derived respiration and root-derived respiration (including actual root respiration and rhizomicrobial respiration): (1) integration of component method, (2) trenching method, (3) root-excising method, (4) gap formation method, (5) root mass extrapolation method, and (6) isotope method. Also there are several methods to separate actual root respiration and rhizomicrobial respiraton: (1) isotope dilution method, (2) model rhizodeposition method, (3) 14CO2 dynamics method, (4) exudate elution method, (5) 13C of CO2 and microbial biomass and (6) combination of some no-isotopic methods. This review has described the basic principles and assumptions of these methods and compared the results obtained in the original research papers.

Key words: soil respiration; SOM-derived respiration; root respiration; rhizomicrobial
respiration

Approach to Mutil-objectives Assessment
for Urban Torrent Hazard

TANG Chuan1， SHI Yu e2
(1. National Laboratory for Geo-hazard Prevention, Chengdu University of Technology, Chengdu 610059;
2. Laboratory of Continertal and Estuarial Morphadynamic, University of Caen,14032 Caen Cedex, France)

Abstract: This paper focuses on the problems of urban torrent hazard in the recent years and reviews the current study status and future research work about assessment of urban torrent hazard. According to torrent-breeding environment, triggering factors, social and economic situation of flooded area, this research formed a GIS based technical methodological system, which is shown as following: collect data→establish database of spatial attribute →choose the system of assessed indexes→analyze forecasting estimation→torrent hazard assessment and risk zonation. Based on this, an integrated methodology for urban torrent risk assessment is approached. Procedure of the methodology for torrent hazard zonation in the flooded area, urban vulnerability analysis, loss evaluation and risk assessment, torrent hazard zonation on the alluvial fan are created via geomorhologic method and the numerical simulation method. Detailed land cover information was derived by using the high resolution satellite imagery and then we evaluated the vulnerability values on different land-use features. Based on a GIS statistical and analytical tool，urban torrent loss and risk for urban area is evaluated. These assessments can be used for torrent mitigation by identifying hazard areas, allowing for avoidance through zoning or other land use policy decision. In addition, residents who live in torrent areas need risk information for evacuation and flood control.

Key words: urban torrent； hazard zonation； vulnerability； loss evaluation； risk assessment

Study on Estimation of Regional Evapotranspiration
by Remote Sensing in the Mu Us Sandland
——A Case Study of Wushen County in Inner Mongolia

ZHOU Huizhen1, LIU Shaomin1, YU Xiaofei1, ZHANG Jinsong2, ZHOU Zefu2, WU Junyi3
(1. State Key Laboratory of Remote Sensing Science, School of Geography, Beijing Normal University,
Beijing 100875, China; 2. Research Institute of Forestry, CAF, Beijing 10091, China；
3. Nalinhe Town forestry centre of Wushen County in Inner Mongolia, Wushen County 017300, China)

Abstract: Accurate estimation of surface evaporatranspiration (ET) is important in the study of global climatic change, scientific management of water resources. In this paper, the evapotranspiration from 1981 to 2003 in Wushen County, located in the Mu Us Sandland, was estimated by using Advection-Aridity Model based on the complementary relationship hypothesis with 1km resolution reflectance data of NOAA/AVHRR and MODIS and meteorology data. The temporal and spatial distribution of ET was analyzed. The results showed: (1) The annual average of ET of Wushen County is 252 mm. Spatially, it increases from northwest to southeast. The multi-year relative variation of ET in Wushen County is from 10% to 24%, larger in northwestern and southeastern parts and smaller in eastern and southern places. Seen from the yearly spatial distribution of the ET, there is the same trend that ET increases from west to east. (2) Ordered in land cover and land use in 2002, ET decreases in following sequence: water body, crop field, grassland, shrub, forestland and sand land. (3) Interannual change of ET in Wushen County is large while the maximum value is up to 300mm and the minimum value is only 200 mm. The monthly distribution of ET takes a ‘bell’ shape, with peak in about July to September.

Key words: surface evapotranspiration；remote sensing；Wushen County in Inner Mongolia

A Landslide Susceptibility Mapping Approach Using Expert
Knowledge and Fuzzy Logic Under GIS

ZHU Axing1,2, PEI Tao1, QIAO JianPing3, CHEN Yongbo3, ZHOU Chenghu1, CAI Qiangguo1
(1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
2. Department of Geography, University of Wisconsin Madison, 550N, Park Street, Madison 53706, USA;
3. Institute of Mountain Hazards and Environment, CAS, Chengdu 610041, China)

Abstract:Current methods cannot meet the needs of evaluating landslide susceptibility because they cannot incorporate the nonlinear relations between landslide and the inducing factors as well as the different forms of relationships. A new approach integrating the expert knowledge and fuzzy logic is proposed in this paper to evaluate the landslide susceptibility. This method first encodes the knowledge from domain experts into four combinations of environmental factors: 1) the difference between slope gradient and the strata gradient as well as the difference between slope orientation and strata orientation, 2) slope gradient and lithology, 3) slope height and lithology, and 4) slope shape and lithology, and thus incorporates the relativity between factors into these combination models. Information on variables involved in these combinations is characterized using a set of GIS techniques. The susceptibility of a given location hence can be evaluated by evaluating each combination and overlaying the values from these four combinations. Some parameters in these models are determined by statistical analysis, and others are provided by landslide experts. The approach is applied to a section of the Three Gorges area from Yunyang to Wushan, and a susceptibility map is produced. The result shows that the computed susceptibility values are much higher over areas with landslides than areas without landslides. We conclude that our approach is capable of capturing the landslide susceptibility.

Key words: landslide; fuzzy induction; slope susceptibility; three gorges; the knowledge from
expert

The Effects of Nitrogen Limitation on Terrestrial Ecosystem
Carbon Cycle: a Review

REN Shujie1,2, CAO Mingkui1, TAO Bo1, LI Kerang1
(1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China;
2. Graduate School of the Chinese Academy of Sciences (GSCAS)，Beijing 100038 )

Abstract: Terrestrial carbon cycle and nitrogen cycle are closely coupled. Some factors, such as temperature, water and CO2 concentration, were more considered in the previous carbon researches than the nitrogen because of the complexity of nitrogen cycle, but this situation has changed in recent years. Nitrogen has great effects on the plant photosynthesis, organic matter decomposition, carbon allocation and the responses of ecosystem when the atmospheric CO2 concentration increases. There are generally three types of carbon models to consider nitrogen limitation on carbon assimilation: (1) static models: these type models usually use a constant soil fertility index or leaf nitrogen concentration and are fit for a site or district where the nitrogen variability can be neglected; (2) soil nitrogen limitation models: these models can maintain stable nitrogen budgets and dynamic soil nitrogen can turn the potential NPP to actual NPP; (3) leaf nitrogen limitation models: such models are similar to soil nitrogen limitation but feature a further dynamic leaf-level nitrogen regulation of NPP. The common approach uses relative leaf nitrogen concentration to scale down proportionally either the maximum Rubisco or the NPP. Although the three type models all consider the nitrogen effects on carbon cycle, they may produce great uncertainty in carbon research because of the partly understanding of the interaction between carbon and nitrogen. Future studies should focus on both the experiment and observation about the nitrogen feedbacks on carbon cycle and the development of integrated dynamic ecosystem models that can describe the interaction of carbon and nitrogen cycle, contributing to decreasing the uncertainty in the carbon research.

Key words: carbon cycle; nitrogen cycle; terrestrial ecosystem; limitation; model

Evaluation of Regional Ecological Security
Based on Dynamic Factors
——A Case Study of Wanquan County, Hebei Province

ZHU Yunhai1, ZHANG Baiping1, CAO Yinxuan2, ZHANG Yunsheng2
(1. LREIS, Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China；
2. Chinese Academy of Surveying and Mapping, Beijing 100039, China)

Abstract: At the beginning of the new century, the issue of ecological security has been put on the agenda of the government in many countries owing to increasingly deteriorating environment of the world. Because regional ecological security serves as the basis of sustainable regional and national development, it comes to be the focus of ecological security. The aim of this study was to develop a comprehensive evaluation system for regional ecological security. Wanquan County of Hebei Province, located in a transitional zone between the farming and pastoral regions, was taken as a case study area. It serves as one of major channels of sandstorm transportation from Inner Mongolia to Beijing. After processing of basic data and in accordance with the principle that evaluating indicators should be dynamic, principal and operable,3 types of evaluating indicators, including vegetation changes, LUCC and soil erosion, were selected. By the comprehensive index method, the dynamic evaluation model was built with the three types of indices based on ecological degradation, and their weights were worked out by introducing least squares solution. And then, the evaluation image for ecological security was generated in ArcGIS9.0/Spatial Analyst module and the model was realized. The final results show that the situation was better in the river area and insecure areas distributed in north part and middle part mainly. An average score of 2.3 in a 4-grade range would not only tell the ecological condition for the entire study area, but also remind the local government to pay more attention to ecology protection. It was proved that dynamic evaluation indicators were superior to static ones for ecological security evaluation, and the least squares solution was a practical and scientific method to balance the weights for evaluation indicators. In addition, the evaluation system was proved to be qualified and synthetically corrected also by applying it to other counties around Beijing.

Key words: ecological security; dynamic evaluation indicators; least squares principle;
Wanquan County

Study on the Theory and Methods of the Identification
of Wetlands Boundary

YIN Shubai1,2, LV Xianguo1
（1. Northeast Institute of Geography and Agricultural Ecology, CAS, Changchun 130012, China;
2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China）

Abstract: Based on the analysis on the difficulty of wetland boundary identification and its causes, and having reviewed the wetland boundary indicators and their criteria selected at present, the paper suggested that, under the condition that the mechanism of wetland formation process has not been fully understood, all of the wetland boundaries based on hydrology and vegetation criteria are to some extent arbitrary boundaries. Wetland boundaries based on arbitrary criteria are not wetland's natural boundaries, because the natural boundaries of any complex can only be cognized, not be “man-prescribed”. Even if there is no controversy on the criteria, it is usually impractical to identify wetland boundaries in the field accurately, because it takes repeated visits over a lengthy period of time(several years), and both seasonal conditions and then recent weather conditions should be considered when these indicators are applied. Wetland boundaries based on instantaneity indicators are unrepeatable and controversial. Aiming to resolve the problems on wetland boundary delineation, the paper analyzed the principles of the System Theory and physical geography related to wetland boundary delineation, and put forward a new method for wetland upper boundary identification. The method suggested that, under the condition that the mechanism of wetland formation processes has not been fully understood, “black box” method of System Theory can be used to identify wetland boundaries scientifically; when it is difficult to identify wetland boundary based on the characteristics of wetlands itself, if the boundaries of aquatic and terrestrial systems can be identified, they can be regarded as the wetland's lower and upper boundaries; the lower limit of rooted plants is chosen as the indicator for delineating wetland lower boundary, and the thinning-out point of the diagnostic horizon of zonal soil is chosen as the indicator for wetland's upper boundary, because the thinning-out point is a kind of critical point, and it can factually reflect the long-term interaction result of all environmental elements. The scientificity and feasibility of the method was also analyzed. The characteristics of the diagnostic horizon, which is less responsive to short-term change than wetland vegetation and hydrology, make sure that the delineating result is repeatable, and that the controversy can be avoided.

Key words: wetland boundary; boundary criteria; soil diagnostic horizon, thinning-out point

Assessing the Impact of Climate Change on Wheat Production
in DingXi (Gan Su province) and HeFei (An Hui Provicve)

TIAN Zhan1,2, XU Xinliang1, SHI Jun1
(1. Shanghai Climate Center Shang Meteorologic Bureau, Shanghai 200032;
2. The Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101)

Abstract: The climate is changing due to higher concentrations of greenhouse gases. If concentrations continue to increase, climate change will be more severe in this century based on climate models project. And it will have significant impacts on many human sectors, especially on agriculture. Agriculture is the foundation of society, especially for China with large population. Wheat is the second most important crop in China. Therefore, it is necessary to assess the impacts of climate change on wheat in China. In order to predict the future risk of climate change on Chinese wheat production, firstly, fifteen-year ECMWF re-analysis data (1979~1993) is used as quasi-observed boundary conditions to drive regional climate modeling system-PRECIS, then the dataset is employed to test the effects of feeding CERES-Wheat model with RCM daily outputs directly via comparing the simulated results and the station observation. Based on the above validation, two wheat stations (Ding Xi and He Fei) were selected to assess the possible changes of future two production under IPCC SRES A2 & B2 scenarios. The rained and irrigated wheat production without and with CO2 fertilization effect, were simulated respectively. It is shown that: regardless of A2 or B2 scenarios, the future climatic change will increase wheat yield both in Dingxi and Hefei to some extent, but the range increased differs greatly. The yield increasing effect of A2 scenario will be generally greater than B2 scenario, the irrigated wheat will benefit more than rainfed wheat, the winter wheat (Hefei ) has larger increasing degree than spring wheat (Dingxi ). With the directly fertilizer effect of CO2, all the treat will increase by a large margin.

Key words: CERES-wheat mode; climate change; RCM

Review and Evaluation of Researches on Urban-Rural
Interaction Development in the Last Fifteen Years

DUAN Juan1,2，WEN Yuyuan3，LU Qi1
(1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China；
2. Graduate School of Chinese Academy of Sciences, Beijing 100039, China； 3. Institute of Regional
Economics and Urban Economics, Renmin University of China, Beijing 100872)

Abstract: Urban-rural interaction development refers to the two-way flowing and optimial allocation of capital, labor, material, information and other socio-economic factors in urban-rural space. Urban-rural interaction development has changed one-way flowing pattern of urban-rural socio-economic factors under urban-rural segregation system, promoting urban-rural common development and overall optimization of regional spatial structure. Meanwhile, in the cross-research field of urban geography and rural geography, urban-rural interaction development will also help to widen research system of geography and provide new research framework for constituting a new round of regional planning and urban-rural planning. Therefore, in the process of building new socialism rural areas and harmonious society, it is necessary to carry out theoretic and practical study on urban-rural interaction development. This article summarized the domestic and foreign research achievements on connotation, mechanism, pattern and way of urban-rural interaction development during the last 15 years, and pointed out that the current researches might mostly favor qualitative and static aspects, while lacking quantitative and dynamic analysis from perspective of the different spatio-temporal dimensions. Therefore, there are three principal issues urgently needed to be solved in the future: (1) Strengthening the research on basic principles of urban-rural interaction development. Spatial economics theory, system science theory and coordination symbiotic theory may be used to analyze the form, content, structure, function and mechanism of urban-rural interaction development. (2) Strengthening the research on mechanism and rule of spatio-temporal evolvement of urban-rural interaction development. Some mathematical methods may be used: firstly, the Two-stage Nested Theil Decomposition method and Exploring Spatial Data Analysis method may be used to reveal the spatial difference of urban-rural interaction development. Secondly, Wavelet Analysis method may be used to reveal temporal variation characteristic of urban-rural interaction development. Thirdly, Grey Association Analysis method and Granger Cause and Effect Analysis method may be used to reveal the relations between urban-rural interaction development and their driving factors. (3) Strengthening the research on the pattern and optimization countermeasure of urban-rural interaction development in different types of regions. Questionnaire and interview methods may be used.
Key words: urban-rural interaction; association; regional planning

Issue No.3

Formation and Evolution of River Terrace and
Environment Responses

WEI Quanwei1, TAN Lihua1, WANG Suiji2
(1. School of Geography, Beijing Normal University, Beijing 100875；
2. Key laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences
and Natural Resources Research, CAS, Beijing 100101)

Abstract: As one of the consequences of historical fluvial evolution, river terrace has recorded some information about environmental changes during river processes. It is the significant geomorphologic complex for analyzing river's historical evolution. This work gives a review on the origin, geomorphologic characteristics, causes of formation, environment responses and the date-measure technology of river terraces as well as its significance in reconstruction of environment during terrace formation. It shows that river terraces are the integrative consequence of the river system and related environment influences. Researchers should consider the entire river system and its environment syntheses to study river terraces. The geological tectonic and climate characteristics and ancient river dynamics may be revealed according to research of river terraces. River terraces are the crucial geomorphologic elements used to reveal the environmental information in study areas. With the development of the meterage instruments, the date-measure technology will be more accurate and sensitive. The dynamic simulation and the quantitative analysis for the formation and evolution of river terraces need more exploration.

Key words: river terrace; causes of formation; environment responses; tectonic processes;
climate change

An Enhanced Method for Spatial Distributing Census Data:
Re-classifying of Rural Residential

YANG Xiaohuan, LIU Yesen, JIANG Dong， LUO Chun, HUANG Yaohuan
(Institute of Geographic Sciences and National Resources Research, CAS, Beijing 100101, China)

Abstract: Spatial distributing of census data is an effective way to integrate statistical data and natural factors. Land-cover and land-use change (LUCC) is the effect of human activities, and spatial distribution of population has close relationship with LUCC pattern both at regional and global scales. Population can be redistributed onto geo-referenced square grids according to this relation. Since there exist efficient approaches for monitoring LUCC with remote sensing and GIS, geo-referenced population data can also be updated conveniently. According to existing methods, it is found that the population density is directly related to land use types and the residential area is the best index for population distribution. Residential areas could be reclassified into three sub classes: urban residential, rural residential, and commercial-industrial. The paper presented an enhanced method for spatial distributing census data: re-classification of rural residential areas. On the basis of the relationship of various kinds of indexes and inhabitation density, several indexes were selected for re-classifying rural residential areas. Using these re-classified rural residential data, the precision of census redistributing pattern was improved obviously. Methods and main algorithms used in these studies were presented in the paper. Characters and prospect of this study were also discussed.

Key words: census data; spatial distributing; rural residential

Progress in Land Surface Temperature Retrieval from Passive Microwave Remotely Sensed Data

JIA Yuanyuan1,2, LI Zhaoliang1
(1. Key Laboratory of Water Cycle and Related Land Surface Processes, Institute of Geographical Sciences
and Natural Resources Research, CAS, Beijing 100101;
2. Graduate School of the Chinese Academy of Sciences, Beijing 100049)

Abstract: Land surface temperature (LST) is of considerable importance for many applications, notably global climatic, hydrological, ecological and biogeochemical studies. In the past two decades, a large number of methods and algorithms have been developed to retrieve cloud free LST from thermal infrared data. As for all optical remote sensing, the Earth observation can only be realized for cloud free condition. In order to get LST for all weather conditions, microwave remotely sensed data, instead of thermal infrared data, from space is commonly used due to its capability to penetrate clouds and to some extent rain. Although the passive microwave remote sensing has some advantages compared to the thermal infrared, there are few algorithms developed to retrieve LST from it, mainly because there are various factors affected the microwave signal. In this paper, we review almost all existing algorithms found in literature, which can be roughly categorized into the statistical-based and physics-based retrieval algorithms, to retrieve LST from passive microwave remotely sensed data. The merits and the disadvantages are summarized for each method respectively. Finally further possible improvement and development directions on the scaling transfer, the microwave radiative transfer modeling and the combination of the different remote sensing data are given for LST retrieval from passive microwave data.

Key words: land surface temperature; passive microwave remote sensing; radiative transfer
model

Spatial Simulation Using GIS and Artificial Neural Network
for Regional Poverty —A Case Study of Maotiaohe
Watershed，Guizhou Province

XU Yueqing1,2, LI Shuangcheng2, CAI Yunlong2
(1. College of Resources and Environment, China Agricultural University, Beijing 100094, China;
2. College of Environmental Sciences, Peking University, Beijing 100871, China)

Abstract: Owing to the fragile eco-environment, terrain fragmentation, and serious soil erosion, the karst area in Southwest China is one of the distinct poor regions. Selecting Maotiaohe watershed as study area, taking villages and towns as studying unit, and using GIS and ANN model, this paper simulates the spatial distribution of natural impoverishing index and socio-economic alleviating impoverishing index, calculates the poverty degree of villages and towns, and reveals the spatial distribution of poverty in order to provide scientific basis for eliminating poverty and ecological reconstruction. The results show that the natural factors such as soil erosion and so on are the main impoverishing indexes, and socio-economic factors are the main alleviating impoverishing indexes. The villages and towns with smaller poverty degree are mainly distributed in the middle and east area of Maotiaohe watershed, and those with larger poverty degree are mainly distributed in the southern and northern area of Maotiaohe watershed. The results also indicate that application of BP neural network to simulating regional poverty is convenient, precise and feasible, which can be an alternative approach to simulating regional poverty.
Key words: regional poverty; spatial simulation; artificial neural network

Review on Study of the Soil Macro-organic Matter

LIANG Aizhen1,3, ZHANG Xiaoping1, YANG Xueming2, FANG Huajun1,3
(1. Northeast Institute of Geography and Agricultural Ecology, CAS, Changchun 130012, China;
2. Harrow Research Centre, Agriculture & Agri-Food Canada, Ontario, N0R 1G0, Canada;
3. Graduate School of the Chinese Academy of Sciences, Beijing 100039, China)

Abstract: Soil macro-organic matter (MOM) with a rapid turnover rate plays a dominant role in soil nutrient dynamics, especially soil nitrogen. MOM is a significant component of light organic matter in soils. It can be a sensitive index to reflect the short-term effects of the management on soil organic matter. This paper reviews the concepts of various soil organic matter(SOM) fractions by different physical fractionations, details the fractionation methods for soil macro-organic matter(MOM), discusses the factors which have influences on the content of the soil MOM，factors which include management, land use, soil texture and climate. In the end, this paper points out the existing problems about the study of MOM:
（1）The dynamic mechanism of soil organic matter is still puzzling.
（2）The procedure for the separation of the soil MOM fraction needs to be studied further.
（3）Many researchers’ opinions diverge from each other on the contribution of MOM to soil nitrogen mineralization.
In future, the study should focus on the mechanism of MOM responding to affecting factors, separating methods and the contribution of MOM to soil nitrogen mineralization.

Key words: soil macro-organic matter; physical fractionation; influencing factors; existing
problems

Aerosol Optical Thickness Retrieving Over Bright Surface：Progress and Prospect

SUN Lin， LIU Qinhuo, LIU Qiang, CHEN Liangfu
（State Key Laboratory of Remote Sensing Science IRSA, CAS， Beijing, 100101）

Abstract: It is a great challenge to retrieve aerosol optical thickness over bright surface from remotely sensed data, because it is very difficult to estimate the reflectance of the complicated surface accurately, and the radiance is not sensitive to the aerosol change when the surface reflectance is high. To overcome the difficulties of aerosol optical thickness retrieving in the bright areas, many methods were provided. We introduced some significant methods: 1) contrast reduction algorithm. This method applied in a sequence of satellite images which contain a clear image; 2) high contrast surfaces algorithm. This method can retrieve aerosol optical thickness from two closely located, high contrast surfaces; 3) two or more sensors cooperation method, which can retrieve aerosol optical thickness together with surface reflectance; 4) methods which are based on surface reflectance database/model, which need to ascertain the surface reflectance accurately. We analyzed the advantages and disadvantages of each method. At last, we provided the prospect of the aerosol optical thickness deriving over bright surface. The construction of surface reflectance database and the development of the BRDF model make the surface reflectance more accurate, the increasing aerosol measuring stations advance our quantitative understanding of aerosol characteristics, and the design of many new satellite sensors which can derive the aerosol optical thickness becomes more perfect. All of the above factors can help aerosol optical thickness retrieving a lot.

Key words: bright surface; aerosol optical thickness; retrieve

Change of Reference Crop Evapotranspiration
from West Songnen Plain

LIANG Liqiao1,3, YAN Minhua2, DENG Wei2, LI Lijuan1
（1. Institute of Geographic Sciences and Natural Resources Research, CAS, Beijing 100101, China;
2. Northeast Institute of Geography and Agricultural Ecology, CAS，Changchun Jilin 130012, China;
3. Graduate University of the Chinese Academy of Sciences, Beijing 100039, China）

Abstract:Reference crop evapotranspiration (ET0) is one of important climate factors, mainly affected by local climate. As related to water balance and energy balance, it decides the shaping and evolvement of geographical environment. With 34 meteorological stations’ data including minimum and maximum air temperature, wind speed, air humidity and sunlight hours from 1951 to 2000, ET0 was obtained by FAO Penman-Monteith equation (P-M) for growing season in western Songnen Plain of Northeast China. Then the authors analyzed the temporal-spatial characteristics of ET0 series with climate diagnostic analysis, and the abrupt change points through point-area integrated analyses by Jy parameter and Mann-Kendall methods. The results show that: (i) the high value of ET0 appears in southwest sandy land, and ET0 gradually decreases northeastwards; (ii) ET0 tends to increase in recent 50 years, and the north area contributes most; (iii) taking 1962 and 1982 as turning points, areal ET0 series indicates evident phase changes during period of 1951~2000; and (iv) two upward and one downward abrupt changes are examined in areal ET0 series, and the time of abrupt changes in typical stations is basically consistent with that in study area, but properties of abrupt changes show evident spatial diversity.

Key words: western Songnen Plain; reference crop evapotranspiration; Penman-Monteith
equation; process in temporal and special changes

Automatic Soil Texture Classification System
Based on Computer Graphics

ZHANG Liping1, 2, ZHANG Yili1, WANG Yingan1, 2
（1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China; 2. Graduate School of the Chinese Academy Sciences, Beijing 100039, China）

Abstract: International and USDA’s soil texture classification systems are prevalent in the world, which adopt additional manual inquiring of triangle coordinate diagram to realize the naming of soil texture. This takes a lot of time and energy and lacks precision control. To apply computer program can perform the same task easily, conveniently and fast. According to the oversea research status quo in soil texture automatic classification based on computer graphics, using Visual Basic（VB） a as platform, soil texture automatic classification system (STAC) is built the better practicability in China. The theories of STAC are mainly based on the fact that each point in the textural triangle represents a unique combination of clay, sand and silt content. For a given textural class, all combinations of clay, sand and silt content are bound by a polygon. Therefore, finding the textural class is equivalent to finding the polygon where the particular combination of clay, sand and silt content is located. The algorithm of the program is point-in-polygon algorithm, which can determine whether a point of known coordinates(clay percentage and sand percentage) lies inside a polygon in the textural triangle. STAC is simple, convenient, fast and explicit. STAC can be used in a Windows 95 console program and above without requiring installation. It realizes texture automatic naming of single as well as batch soil data and provides graphical display, statistics and analysis function, and user-defined classification, and can classify several thousands of soil samples in about a second.

Key words: soil texture; plane triangle coordinate diagram; computer graphics; automatic
classification

Research Progress on Urban Air Quality Health Risk Assessment

ZHANG Li1,2, WANG Wuyi1, LIAO Yongfeng1,3
(1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101; China； 2. Graduate School, CAS, Beijing 100049， China； 3. National Disaster Reduction Center of China, Beijing 100053， China)

Abstract: At present, air pollution draws attention of many researchers and officials from all countries to the latent impacts to human health in the world, along with the development of industrialization and urbanization. Study focus is to assess health effects of exposure to pollutants. Recently health risk assessment of air pollution is being developed at home and abroad. The full risk assessment process includes identification of pollutant concentration，exposure assessment, dose and effect assessment and expression of human health risk. The authors introduce research progress in urban air quality simulation, human exposure, air pollutant toxicology and health effect, and GIS operation in health risk assessment in recent years. Having analysed existing researches, the authors find some research limits, including: 1. Research scale are restricted to small regions, and data from limit inspect stations can’t assess broad regions, such as megapolis; 2. Applied methods usually are qualitative although some are semi-quantitative assessment on the basis of WHO air quality health effect standard; 3. Indexes of human effect mainly are morbidity and mortality, and seldom research touches on health risk of exposed population; 4. Some researches focus on conventional pollutants health effect in short term, and little involve comparatively sensitive traffic pollutant health effect. In order to serve population, future research should concentrate on simulating microscopic urban air quality, structuring quantitative assessment based on exposure-dose relationship and developing long-term pollutant health effect models according to actually absorbed dose.

Key words: urban air quality; human health; risk assessment

The Progress and Prospect of Land Use Conflicts

YU Bohua1,2，LV Changhe1
（1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101, China；
2. Graduate School of the Chinese Academy of Science, Beijing 100039, China）

Abstract: Varied demands of society for the limited land are leading to an overlay of interests and thus to land use conflicts. Moreover, the conflicts are exacerbated by the rapid increase of population and urban expansion on both regional and global scale, which is an obstacle for sustainable land use. It is becoming increasingly challenging for local and national government over land management. Thereby, the study of land use conflicts plays an important role in the realization of sustainable land use. This article examines the causes of land use conflicts from both physical and social-economic dimensions, and regards that scarces of land resource and increasing conflicting demands for land should be responsible for land use conflicts. Conflicts among economical, environmental and social objectives are this articles main contents. Farming-pastoral region, water-land ecotone and urban-rural fringe are the three hotspots of multiple conflicts. The article also describes familiar methods used in the study of resource use conflicts, with a hope to help the study of land use conflicts. There is still a long way to define and understand the concept of land use conflict and its connotation, to pursue its driving forces and countermeasures. In the future the emphases of land use conflicts study should focus on tracing and monitoring the dynamics of land use conflicts in order to create a better basis for understanding the conflicts and also on the contrast of internal and external conflicts from the context of occurrence and evolution. The models or tools should also be developed at the same time in order to reduce land use conflicts in terms of a regional management of environment and natural resources.

Key words: land use conflicts; stakeholders; conflicting interests; hotspots; land use
management

The Progress and Prospect of Stable Isotopes in Plants

WU Shaohong1,2, PAN Tao1,3, DAI Erfu1
(1. Institute of Geographical Sciences and Natural Resources Research, CAS Beijing, 100101;
2. Institute of Tibetan Plateau Research, CAS Beijing 100085；
3. Graduate University of the Chinese Academy of Sciences, Beijing, 100049)

Abstract: Stable isotopes in plants are widely applied in geographical and ecological studies in the recent years internationally, which combine long-term biogeochemical process and integrate different systemic components. Researches on stable isotopes of plants aim at studying temporal and spatial information of environmental factors, and revealing the trends of climate change and the geographical distribution characteristic. Abundant environmental and climatic information is recorded by stable isotopes in plants, such as information on temperature, humidity, precipitation and environment isotopes composition. The latest progresses over the world are reviewed in this paper, including the basic theories, research methods and main application areas. Review of researches on stable isotopes in plants on national and international literatures shows that stable isotopes in plants have close relation with environmental factors. The technology of stable isotopes in plants is mostly used to rebuild historical climate series, and recovers isotopes composition and concentration trends of CO2 in the atmosphere. Analysis of the features of isotopes in plants indicates that stable isotopes in plants could not only be applied to studying climate change, but also to detect regional environmental differences which has an important future for application. Study shows that the 18O in plants came only from H2O. Therefore, the origin of vapor in plants is one of the most important factors of the δ18O composition in plant, especially in typical monsoon regions. So it is possible to estimate the respective affected areas of different monsoons, and to study the spatial pattern of monsoon climate.

Key words: plants; stable isotopes; fraction; climate change; district environmental difference

A Review of Distributed Model for Soil Erosion
and Sediment Yield

CAI Qiangguo1， YUAN Zaijian1，2，3， CHENG Qinjuan1，2， QIN Jie1，4
（1. Institute of Geographical Sciences and Natural Resources Research, Key Laboratory of Water Cycle & Related Land Surface Processes, CAS, Beijing 100101, China；
2. Graduate School of the Chinese Academy of Sciences, Beijing 100049, China；
3. School of Economics & Management，Hebei University of Science & Technology，Shijiazhuang
050018， China； 4. Huazhong Agricultural University，Wuhan 430070， China）

Abstract: With the development of computer and GIS, distributed model for soil erosion and sediment yield has become the developing direction in the field of soil erosion. This paper discussed the technical route and realization of distributed model based on the analysis of the main distributed models home and abroad at present. Finally, the paper indicated some problems of the distributed models for soil erosion and sediment yield in our country:（1） there are many problems in the developing of distributed models for soil erosion and sediment yield which are based on the distributed hydrological models, although the latter provides many references for study of the former；（2） the distributed models for soil erosion and sediment yield are mainly based on the loess plateau and the models are regional at present in our county；（3） most relational expressions of soil erosion and sediment are mainly empirical and the process of soil influx is simply beginning to be considered nowadays；（4） the spatial and temporal change of single rain event was ignored in most distributed models for soil erosion and sediment yield at present. In the future, the above problems should be solved in the constructing of distributed model for soil erosion and sediment yield in our country.
Key words: GIS; distributed model for soil erosion and sediment yield; soil erosion; technical
realization

Formation Background of the Zhalong Wetland and
its Eco-environmental Significance

YIN Zhiqiang1, QIN Xiaoguang1, LIU Jiaqi1, QIU Shanwen2
(1. Institute of Geology and Geophysics, CAS, Beijing 100029, China;
2. Northeast Institute of Geography and Agricultural Ecology, CAS, Changchun 130012,China)

Abstract: Zhalong wetland locates at the western part of Heilongjiang province and was developed from the terminal lake of the Wuyuer river. In this paper, the geological environment of the Zhalong area and the relationships among the Zhalong wetland, the Nenjiang river and the Songnen desert were studied by field survey, soil sample analysis and remotely sensed image interpretation. It was found that the desert from Qiqihaer to Daqi consisted of NW-extended dunes and saline, forming a NE-extended dune belt with Keerqin desert together. The desert was mainly developed from the last glacial period. After that, the Nenjiang river flowed through the dune area and rebuilt the dunes and a lot of yoke lakes were left in Zhalong area. Because of the crustal tectonic uplift in the Zhalong area, the Nenjiang river moved westwards and Wuyuer river became an inner river which terminal lake evolved and developed as the present Zhalong wetland eventually. So the environmental evolution of the Zhalong area since the last glacial period was concluded as: the wind-blown dune belt formed → the Nenjiang river rebuilt the dune belt → the Nenjiang river westwardly migrated and the Wuyuer river became an inner river → the terminal lake of the Wuyuer river evolved to the Zhalong wetland. Therefore, the Zhalong wetland and the Lianhuan lake developed on an once-existed desert, suggesting that the eco-environment of the area is the frailest in the whole Nenjiang watershed. It means that the salinification and desertation in the area would rapidly develop and severely affect the eco-environment of the Qiqihaer-Daqi area if the Zhalong wetland disappeared.

Key words: the Zhalong wetland；remotely sensed image；environmental evolution

The Effects of Land Use Change on Land Quality at Patch
Scale — A Case Study in Zhangbei County, Hebei Province

GUO Xudong, XIE Junqi, HE Ting
( Key Laboratory of Land Use, Ministry of Land and Resources,
China Land Surveying & Planning Institute, Beijing 100035, China )

Abstract: Huge press on natural resources and environment in China requires the study of the regional land quality pertinent to land degradation. Land use, which is exhibited as patches in space, has a close relationship with land quality. The research of the relationship between land use and land quality at patch scale can improve our under standing of the effects land use changes on land quality. The Ministry of Land and Resources implemented “Remote Sensing Monitoring on Land Resources and Eco-environment in Area around Beijng” and “Remote Sensing Monitoring Study for Distribution of Cultivated Farmland and Grain for Green in Typical Regions around Beijing” projects from 2002 to 2004. With the help of the project’s achievements, the cultivated farmland changes in Zhangbei County, Hebei province, from 1999 to 2003 were analyzed by using the SPOT2/4 and SPOT5 remote sensing data. The degradation character of changed patches from cultivated land in 1999 to grassland and forest land in 2003, from grassland and forest land in 1999 to cultivated land in 2003 and unchanged cultivated land were analyzed by the application of GIS and statistical methods. The cultivated land decreased by 20229.5ha in 2003 compared to 1999, most of which turned into grassland and forest land, and the main type is the change of farmland to man-made grassland. The most of newly increased cultivated land came from grassland. The area of un-degraded patches in all types from cultivated land to grassland and forest land, except the change from farmland to low-density forest land, are larger than degraded patches, indicating these change types could lead to a higher land quality. The changed patches from forest land to farmland and from grassland to irrigated farmland have an obvious degradation inclination; however, the proportion of changed patches’ area and quantities from grassland to farmland, from other land to farmland and from grassland to vegetable land is not large. Compared to un-changed cultivated patches, the area proportion of undegraded patches to total changed patches from farmland to grassland is larger and the quantity proportion is similar; the area and quantity proportion from farmland to grassland is not different largely. Both area and quantity proportions of un-degraded patches from farmland to forest land are larger than those from forest land to farmland. These results indicate the transition from farmland to forest land and grassland can improve the regional land quality.

Key words：land use change; land degradation; land quality; patch scale

Analysis of Vegetation Change in Mt. Qomolangma
Natural Reserver

ZHANG Wei1,2, ZHANG Yili1, WANG Zhaofeng1,2, DING Mingjun1,2, YANG Xuchao1,2
LIN Xuedong2,3, YAN Yuping4
（1. Institute of Geographical Sciences and Natural Resources Research, CAS, Beijing 100101；
2. Graduate School of the Chinese Academy of Sciences, Beijing 100039；
3. Institute of Tibetan Plateau Research, CAS, Beijing 100085；
4. Laboratory for Climate Studies, CMA, Beijing 100081）

Abstract: Based on the NOAA AVHRR-NDVI data from 1981 to 2001, digitalized China Vegetation Map (1∶1 000 000), temperature and precipitation data, DEM， and spatial people density data in 2000, the spatial patterns and characteristics along the altitude gradients of the vegetation change as well as their factors in Mt. Qomolangma Natural Reserver have been studied. The results show that: (a) there are notable spatial differences of vegetation change in Mt. Qomolangma Natural Reserver and stability is the most common status. 5.09 percent of the whole area is becoming serious degradation, 13.34 percent degraded, 54.31 percent keeping stable, 26.31 percent turning better and 0.95 percent notably turning better. The degradation and serious degradation areas mostly lie in the south of the Reserver, which are along the national boundaries. The areas of vegetation turning better lie in the north of the Reserver and the south side of the Yarlung Zangbo River. The stable areas lie between the better and worse areas. Along with the increase of elevation, the states of vegetation changes transit from degradation to stability. At the altitude from 2400m to 4000m vegetations are in degraded change condition while at the altitude from 4000m to 6000m vegetations are stable. (b) The degenerated objects in Mt. Qomolangma Natural Reserver are most composed of shrubs, needle-leaf forests and needle-leaf and broad-leaf mixed forests. Plant changes can be divided into three types: (1)Stable to growing better. They are steppes and meadows. (2)Stable to degraded. They are shrubs and alpine sparse vegetation. (3)Degraded. They are needle-leaf forests and needle-leaf and broad-leaf mixed forests. (c) The temperature change affects vegetation change in space while the integration of temperature changes and slopes affects vegetation change along the altitude gradients. Spatial correlation coefficient of temperature change and NDVI change is 0.51. Correlation coefficients along the altitude gradients of temperature change and NDVI change and slope and NDVI change are 0.946 and -0.896. (d) Unconscionable resource use mode made by human beings leads to the vegetation degeneration in some parts of Mt. Qomolangma Natural Reserver. Bio-resources are continually used to meet the need of economic development and human living, which are hard to regenerate in such a rigorous environment. Because of poverty and severe environment in Mt. Qomolangma Natural Reserver, sustainable development should be consistent with economic development. A series of adaptive policies and modes such as protecting bio-resources, altering industry structures and eliminating hunger and poverty should be taken to keep sustainable development.

Key words: Mt. Qomolangma; natural reserver; vegetation degeneration; altitude gradients;
resource use mode