Table of Content

    25 September 2010, Volume 29 Issue 9 Previous Issue    Next Issue
    Original Articles
    Several Problems in the Study on Integrated Evaluation of Security Risks of China's Energy and Water Resources
    ZHENG Jingyun, HE Fanneng, WU Wenxiang
    2010, 29 (9):  1027-1031.  doi: 10.11820/dlkxjz.2010.09.001
    Abstract ( )   PDF (827KB) ( )   Save

    The study of integrated evaluation on security risks of energy the international integrated risk governance researches. This study not only concerns about the achievement of sustainable development and the building of a harmonious society, but also the establishment of the scientific and technological innovation system in China. This paper introduces the objective and contents of the study on integrated evaluation of energy and water resources' security risks, build a conceptual framework of risk evaluation, and analyzes main technical difficulties and problems in such studies. The purpose of this paper is to provide the basis for further studies on the integrated governance of energy and water resources security in China.

    References | Related Articles | Metrics
    Risk Assessment on Water Resource Utilization in the Songliao Basin by Spatial Cluster Analysis
    ZHANG Xuexia, WU Peng, LIU Qiyong
    2010, 29 (9):  1032-1040.  doi: 10.11820/dlkxjz.2010.09.002
    Abstract ( )   PDF (1425KB) ( )   Save

    With the socio-economic development, water demand is increasing, and the conllicts between water supply and water demand at regional scales become increasingly significant. Scientific evaluation on the risk that caused by the conllicts between supply and demand of water resources is essential to the elimination of the imbalance. This paper analyzes the utilization of water resources in the Songliao Basin based on the water quantity, water quality and socio-economic data in 1999-2006, and generates a risk evaluation index system of water resources utilization, which included 10 indicators. Three common factors including high water demand, high water supply and low-quality water were used in factor analysis. The three common factors were assessed with spatial clustering, and the risk distribution of water resources in the Songliao Basin was estimated. The research results show that the pattern of water resource utilization in the Songliao Basin is that high risks is in the center, with low risk around the basin. Nen River and Songhua River have high risks and Tumen River and Wusuli River have low risks.

    References | Related Articles | Metrics
    Framework for Water Scarcity Assessment and Solution at Regional Scales: A Case Study in Beijing-Tianjin-Tangshan Region
    LI Jiuyi, LI Lijuan, LIU Yumei, LIANG Liqiao, LI Bin
    2010, 29 (9):  1041-1048.  doi: 10.11820/dlkxjz.2010.09.003
    Abstract ( )   PDF (1217KB) ( )   Save

    Water scarcity risk assessment is a research hotspot worldwide. Regional scale risk assessment is more complex than that at a city scale because of the internal differences. A water scarcity risk assessment and decision-making system as established at a regional level in this article, which constituted by four indexes, i.e. the demand satisfaction index, the demand reliability index, the rate of water resources utilization, and water-use efficiency. A case study in the Beijing-Tianjin-Tangshan region was conducted. The results show that the water scarcity risk level of Beijing, Tianjin, Chengde and Zhangjiakou is lower in 2020, better than the present situations. The risk level of Qinhuangdao is moderate, and that of Tangshan and Langfang is high. Saving water and unconventional water use should be wildely adopted in this region. Besides, water supply to Tangshan should be increased to reduce the water scarcity risk. In Langfeng, agricultural water demand should be decreased by reducing the multiple cropping indexes. This system can directly reflect the probability of water scarcity and the capacity to avoid risks. Reasonable water resource management decision -making can be made based on this study because the characteristics of regional water scarcity are clearly revealed by the four indexes.

    References | Related Articles | Metrics
    Analysis on Mainland China's Solar Energy Distribution and Potential to Utilize Solar Energy as an Alternative Energy Source
    LI Ke, HE Fanneng
    2010, 29 (9):  1049-1054.  doi: 10.11820/dlkxjz.2010.09.004
    Abstract ( )   PDF (43472KB) ( )   Save

    With rapid population growing and dramatic industrial economy developing, the world faces the dual challenges of massive energy requirements and environmental issuescaused by extensive fossil fuel depletion. One of the main candidates for faxing these challenges are renewable sources of energy (including solar, wind, biomass, geothermal, hydro,wave and tidal energies). Among these sources, solar energy comes at the top of the list due to its abundance, and more even distribution in nature than any other renewable energy types. However, analyses of China's solar energy potential so far have generally relied onclimatological empirical formula which is hard to spread and undeveloped drawing technique. Therefore, based on general solar radiation observations taken from 99 China's radiation stations and sunshine duration observations taken from 387 of China's 752 meteorological stations, this textcpunted average annual solar total radiation as the factor of abundance, sunshine duration as the factor of stabilization and available sunshine days(≥3 hours) as the factor of guarantee from the years 1995-2004. Using ArcGIS cartography software and the aforementioned data, the following text depicted a series of maps of mainland China's solar energy distribution. Then these maps were overlaid to present a more accurate picture of mainland China's solar energy potential. An analysis of these maps leads to the following conclusions. The greatest solar energy potential is in the Qingzang Plateau, Northern Gansu, Eastern Xinjiang and Mid-Western Inner Mongolia, where are the best locations for extensive solar energy utilization; solar energy potential in Xinjiang, Eastern Inner Mongolia, western part of Northeast Plain, Northern Hebei and Ningxia, Southeast Qinghai and Western Sichuan, is the second best, also perfect for solar energy development. In the areas of the northeast part of Northeast Plain, most parts of Loess Plateau, Yunnan and Hainan, Northern Huabei Plain, and Northern Xinjiang, solar energy potential is at average level. The other areas of mainland China have small solar energy potentials due to the lack of solar radiation.

    References | Related Articles | Metrics
    Empirical Study for Comprehensive Appraisal of Coal and Oil Security Risk: A Case study in Beijing and Zhejiang
    WEI Danqing, ZHAO Jian'an, LI Hongqiang, LANG Yihuan
    2010, 29 (9):  1055-1059.  doi: 10.11820/dlkxjz.2010.09.005
    Abstract ( )   PDF (888KB) ( )   Save

    On the basis of the risk appraisal index system of coal and oil, a risk appraisal model for the comprehensive risk degrees was established and the degrees of various risk sources for the coal and oil security were estimated. In this paper, we use the AHP and 14 indicators to calculate the risk indexes, and made a comprehensive grading of the coal and oil security risk, and classified the possibility of risks into the lowest, low, medium, high and very high levels. Concerning the comprehensive risk index (ECSRI), 0-0.2 is I (the lowest), 0.20.4 is Ⅱ(low), 0.4-0.6 is Ⅲ (medium), 0.6-0.8 is Ⅳ (high), and ≥0.8 is V (very high). We applied the system to the empirical research in Beijing and Zhejiang, two regions with high levels of social and economic development in eastern China, obtained the comprehensive risk degrees and the degrees of various risk sources for the coal and oil security for this two places, and then evaluated coal and oil security risk ratings. The result is that coal security risk ratings of Beijing and Zhejiang are at the lower and medium levels respectively. The rating for Beijing is 0.3160 and for Zhejiang is 0.4725. Oil security risk ratings are at medium and higher levels (Beijing is 0.4840 and Zhejang is 0.6371). Compared with the actual coal and oil security of these two places, the result is generally coincident with the reality, and thus confirmed the reliability of the index system and evaluation method. At the same time, the empirical results also predicted the risk probability of two places within the next few years. }

    References | Related Articles | Metrics
    Land Use System Dynamic Modeling: Literature Review and Future Research Direction in China
    PEI Bin, PAN Tao
    2010, 29 (9):  1060-1066.  doi: 10.11820/dlkxjz.2010.09.006
    Abstract ( )   PDF (858KB) ( )   Save

    The dynamic inter-relationship of land use/cover change (LUCC) and its environment has been one of the major issues since the LUCC study started in the 1980x. To integrate both processes of land user’s decision making and environmental change to investigate land use system dynamics is one of the feasible approaches to couple physical system and social syetem into a more complicated land use system. Based on the complexity analysis of land use system, this paper summarizes the major research problems in LUCC modeling, including (1) how to analyze the influence of physical characteristics on decision making process, (2) how to quantify the interaction between different user, and (3) how to build regional land use dynamic models. Models are recongnized as one of the powerful methods to study the structure and function of land use system. Till now, few models can truly intergrate the physical subsystem and socio-economic subsystem into more comprehensive models to simulate more realistically the land use change processes. While the agent based modeling (ABM), which considers the spatial dimension and the decision making process of land use change, is more suitable for simulating land use change process on spatial, interactive and multi-scale dimensions. Based on the review of the researches on agent based modeling of land use change, this paper proposes some suggestions for such works in China.

    References | Related Articles | Metrics
    Agricultural Land Use Responses to Increasing Labor Opportunity Cost in Suixian County of Henan Province
    CHEN Yuqi, LI Xiubin, ZHU Huiyi, ZHANG Wen
    2010, 29 (9):  1067-1074.  doi: 10.11820/dlkxjz.2010.09.007
    Abstract ( )   PDF (1324KB) ( )   Save

    Increasing labor opportunity cost has become one of the most important influencing factors for agricultural land use changes. Based on 328 household survey data in Suixian County, Henan Province, this paper analyzed the types of labor employment and non-agricultural work time and wages, and then calculated the labor opportunity cost by using different labor types’ chances of getting non-agricultural job as the correction factor to amend wages. It was found that labor opportunity cost significantly affected land use practices of rural households. Households with higher labor opportunity cost always have higher nonfarm income. They are less dependent on agricultural production and more likely to lease their cultivated land to other farmers. These farmers are also inclined to grow food craps which need less labor inputs but have higher labor productivity. This results in homogenization of regional land use structure in terms of crop types. As to land use intensity, along with the increase of labor opportunity cost, labor intensity and yield -increasing inputs in agriculture decrease rapidly, while labor-saving inputs show an increasing trend. The households with larger labor opportunity cost are willing to increase machinery inputs as a substitute for labor inputs. Because of the reduction of yield-increasing inputs, the households with larger labor opportunity cost have lower grain yield per area

    References | Related Articles | Metrics
    Analysis on the Spatio-temporal Variation of Grassland Cover Using SPOT NDVI in Qilian Mountains
    DAI Shengpei, ZHANG Bo, WANG Haijun, WANG Yamin, LI Dan, WANG Xingmei
    2010, 29 (9):  1075-1080.  doi: 10.11820/dlkxjz.2010.09.008
    Abstract ( )   PDF (1337KB) ( )   Save

    Based on RS and GIS technology, the grassland cover spatio-temporal variation of Qilian Mountains was analyzed using cumulative average method, average method, trend line analysis, image differencing with the SPOT VGT-NDVI data, and Hurst exponents were utilized to predict the future trends of grassland cover change in Qilian Mountains. The results show that: (1) the grassland vegetation NDVI has been in creused in Qilian Mountains from 1999 to 2007. The increase rate of annual average NDVI and growing season NDVI in typical steppe and plain grasslands was higher than that in alpine meadow and desert grasslands. The increased and reduced areas were 69776 km2 and 15928 km2, respectively. The grassland vegetation NDVI in Lenglong Ridge, Laji Mt., Datong Mt., Daban Mt., South Qinghai Mt., Zongwulong Mt., Tuolai Mt., South Tuolai Mt. was improved, and comparatively, the grassland vegetation NDVI was reduced in Wushao Ridge, the valleys of Datong River, Shiyang River, Heihe River, Beida River and Shule River and the surrounding areas of Qinghai Lake. (2) The grassland vegetation NDVI of Qilian Mountains with a single peak curve during the year changer in Qilian Mountains. (3) The grassland cover in Lenglong Ridge, Zongwulong Mt., South Qinghai Mt., Jingtie Mt., Laji Mt., Wushao Ridge; the valley of Datong River, Hei River, Beida River, Shule River and the surrounding areas of Qinghai Lake will be sustainably improved in the future, and the grassland cover will be degraded in South Zoulang Mt., Tuolai Mt., South Tuolai Mt., Datong Mt. and the valleys of Huangshui and Shiyang rivers. The cover of desert grasslands and alpine meadow grasslands will be improved, and the typical steppe and plain grasslands will be degraded in the future.

    References | Related Articles | Metrics
    Impact of Land Use on Input and Export of Nitrogen of Watersheds: A Case Study in San Joaquin Valley, CA
    HAN Zhen, LUO Yuzhou, WANG Zhonggen, Randy A. Dahlgren, Minghua ZHANG
    2010, 29 (9):  1081-1086.  doi: 10.11820/dlkxjz.2010.09.009
    Abstract ( )   PDF (872KB) ( )   Save

    Land Use influences the spatial distribution of nitrogen (N) inputs in watersheds and the transportation of N to rivers, and is therefore clowly related to non-point pollution. Here we took San Joaquin Valley, one of the most important agricultural areas in the United States, as an example to analyze the impacts of land use on input and riverine N export in this area. Total N loads were monitored at five mainstream sites and four tributary sites along San Joaquin River. The spatially explicit calculation of N input8 for the nine corresponding watersheds was conducted with GIS (Geographic Information Systems). The inputs were calculated as the sum of inorganic fertilizer, organic manure, atmospheric deposition, natural fixation, and crop fixation. The N in water removal and harvest was subtracted. Results showed that total N inputs ranged from 3607 to 12301 kg km-2 yr-1, among which inorganic fertilizer (42%-65%) and organic manure (26%-48%) were the largest sources. The proportion of N inputs exported through rivers ranged介om 0.1% to 8.87%. A new index:F=CN/(L/Q) was developed to characterize the variability of the fractional N export from the watersheds. CN (Curve Number), an empirical parameter from SWAT (Soil and Water Analysis Tool), was used to represent in-field yield of N in agricultural areas. Larger CN indicates larger potential to produce runoff that flushes N into the receiving river channels. L/Q (L: Rivermile, Q:Streamflow) was used to represent the N transport processes in river channels. Regression analysis showed that there was a strong linear correlation between F and fractional N export. The index F has the advantage in using readily available factors to predit trends of N loads in areas which have similar(limate and landscape. Using the product of F and rate of inorganic fertilization, agricultural fields that have high risk of N pollution were identified. The larger value of IFR.F indicates intensive fertilizer application and high runoff potential. We suggested that management and monitoring practices should be applied intensively in these areas.

    References | Related Articles | Metrics
    Study on the Boundary and the Area of Badain Jaran Desert Based on Remote Sensing Imagery
    ZHU Jinfeng, WANG Nai'ang, CHEN Hongbao, DONG Chunyu, ZHANG Hua'an
    2010, 29 (9):  1087-1094.  doi: 10.11820/dlkxjz.2010.09.010
    Abstract ( )   PDF (1620KB) ( )   Save

    The Badain Jaran Desert is a unique geomorphic unit with the world's highest sand hill and more than 100 lakes. However, there are different opinions on the boundary and the area of it, leading to the question whether its area is the second or the third in China. According to latest research achievements and extensive fieldwarks in 2009, questions related to the boundary and the area of the desert have been dealt with in the view of geography. By using the Landsat7-ETM+ images and GIS and GPS methods, the boundary of the Badain Jaran Desert was investigated and the area of it was reexamined. The results show that the Badain Jaran Desert starts from the southeastern edge of the Yabulai Salt Lake and Yabulai Mount and the eastern edge of the Zangnai Mount and S218 National Road, cannects with the western edge of the Zhengyi Valley on Heihe River, and reaches Ruashui River and Gurinai Lake. The north of it is the Guaizi Lake and the Ancient Juyan Lake. The south of it is the Heli Mount, Beida Mount and Heishan Mount. The Badain Jaran Desert crasses a langitude of 5 degrees with a length of 442 km from east to west, and a latitude of 3 degrees with a length of 354 km from south to north. It ranges from 39°04'15"N to 42°12'23"N and from 99°23‘18"E to 104°34'02"E, cavering an area of 52.162x103 km2. The Badain Jaran Desert cavers 7 caunties (banners or district)in 2 provinces. Therefore, it can be cincluded that the Badain Jaran is the second largest desert in China.

    References | Related Articles | Metrics
    Ecological Safety Evaluation of Three Gorges Reservoir Area in Chongqing with the Pressure-State-Response Model
    WEI Xingping
    2010, 29 (9):  1095-1099.  doi: 10.11820/dlkxjz.2010.09.011
    Abstract ( )   PDF (893KB) ( )   Save

    An ecological safety index (ESI) system including 20 indices for the Three Gorges Reservoir area in Chongqing was built up following the principles of the pressure-state-sponse (P-S-R) model. The ecological safety problems were analysed through standardizing the primary data, estimating values of weight and construtting models for ecological safety evaluation. The study results was made more reasonable by using the average means of the results from the entropy method and AHP method as comprehensive weight values. The Recults showed that the Three Gorges Reservoir area in Chongqing was kept at a very unsafe state from 1997 to 2003 and kept at an unsafe state from 2004 to 2007. The resource environment was at very unsafe state from 1997 to 1999, unsafe state in both 2000 and 2001, critioal safe state from 2002 to 2006 and relative safe state in 2007. The human enviroment response was at very unsafe state from 1997 to 2004 and unsafe state from 2005 to 2007. The affeoting degrees on urban eoologioal safety of the factors in the PSR model follow a desoending order of human enviromental response, resource environmental state and resource environmental pressure m turns.

    References | Related Articles | Metrics
    Modeling the Distribution of Permafrost along a Transportation Corridor from Cetar to Muri in Qinghai Province
    LI Jing, SHENG Yu, CHEN Ji, WU Jichun
    2010, 29 (9):  1100-1106.  doi: 10.11820/dlkxjz.2010.09.012
    Abstract ( )   PDF (1309KB) ( )   Save

    Taking the lOkm-wide buffer areas along the traffic lines, the Cetar-Muri Railway and the ReshuiJiangoang Road, in Qinghai province as the research areas, this paper studies the distribution patterns of permafrost in the buffer area. Boreholes, which were drilled in the fields and used to determine the existence of perfamost at the drilling points, were the data basis. Based on the 189 boreholes and DEM, effects of longitude, latitude, elevation, solar radiation, aspect,slope and curvature on the distribution of permafrost were evaluated quantitatively through the(orrelation analysis. The results indicated that the macro-scale factors of longitude, latitude, elevation and solar radiation were the major affecting factors. As the spatial scale decreused, slope was another important factor affeoting the distribution of perma frost Therefore, a logistio model, baking longitude, elevation and slope as independent variables, and the occurrenoe probability of permafrost as a dependant variable, was developed to simulate the distribution probability of permafrost in the buffer areas. The modeling results showed that the possible permafrost with probability values ranging from 0.75 to 1 was the major type, accpunting for 65% of the buffer area. The second largest distribution area was the seasonally frozen ground with probability values smaller than 0.5, accpunting for 29% of the buffer area. The third was the possible permafrost type with probability values of 0.5-0.75, accpunting for only 6% of the buffer area.

    References | Related Articles | Metrics
    Ecological Sustainability Assessment Based on Material Flow Analysis: A Case Study in Shenzhen City
    HUANG Songlin, WU Jiansheng, PENG Jian, HUANG Xiulan
    2010, 29 (9):  1107-1114.  doi: 10.11820/dlkxjz.2010.09.013
    Abstract ( )   PDF (1312KB) ( )   Save

    To study the relationship between economic development and environmental pressures of the economic system, the material inputs and outputs of the economic system in Shenzhen City during the period from 1992 to 2007 were calculated and analyzed by the material flow analysis (MFA). The material intensity and material efficiency in Shenzhen were compared with other distrios using the same indicators. The results showed that Shenzhen relied greatly on outside resources and the material inputs of its economic system changed obviously in 2004. The key point for controlling material consumption was to control the amount of material inputs. Shenzhen is on the third stage of city development, and the material inputs go down slowly and the material outputs rise. Shenzhen is getting ride of the reliance on the outside materials step by step but the eeo-environmental system is still under a great pressure. Shenzhen’s resource production efficiency and environment efficiency are improving. The improvement of technology increases the efficiency of material use. So the costs of material consumption and environment pollution are becoming lower and lower. The interaction between economic system and eco-environmental system can be divided into two stages. Shenzhen is now experiencing the transformations from relative sustainable development to absolute sustainable development.

    References | Related Articles | Metrics
    Spatial-temporal Pattern of Potential Evapotranspirations in Xiliaohe Watershed
    ZHANG Weike, YANG Yanzhao, FENG Zhiming, SUN Xiaozhou
    2010, 29 (9):  1115-1120.  doi: 10.11820/dlkxjz.2010.09.014
    Abstract ( )   PDF (1094KB) ( )   Save

    In China, the farming-pastoral zone of northern China has become one of the academic research hot spots. Xiliaohe watershed is a part of the farming-pastoral zone of northern China, located in the east of Three North Area of China. Horqin sandy land is in this watershed, which is well known as the biggest sandy in China. Xiliaohe watershed’s weather is meteorological drought with less rain. And the evapotranspiration is strong. The situation of water shortage is serious. Water shortage has become the bottleneck to the development of local in dustry and agriculture. Also, Xiliaohe watershed is considered as a vulnerable eco-region because of water shortage. Potential evapotranspiration, seen as the basis for the actual evapotranspiration research, is important not only to the water resources research but also to the study of the relationship between vegetation and mois ture. This study aims at analyzing the spatial-temporal pattern of potential evapotranspiration in the Xiliaohe watershed. Based on the(limatic data from 45 meteorological stations throughout the Xiliaohe watershed during 1974 and 2005, potential evapotranspirations (ET0) are calculated using the CI method (Calculate first, Interpo late later). Firstly, potential evapotranspirations of 45 meteorological stations are calculated using the Penman Monteith (98) Model recommended by FAO. Secondly, based on the ArcGIS 9.0 software, using the Ordinary Kriging method, potential evapotranspirations in Xiliaohe watershed are interpolated month by month. Conclu signs are as follows: 1) ET0 is positively related to temperature, sunshine hours and wind speed but inversely related to average relative humidity. 2) Affected by the impact of various meteorological elements, the monthly ET0 change curve is a single peak curve. ET0 is always lower in winter and higher in summer, the end of spring and the beginning of autumn. 3) The spatial distributional trend of potential evapotranspirations in Xiliaohe water shed is that ET0 decreases gradually from the Horqin sandy land (the middle of the Xiliaohe watershed) to the northeastern side and southwestern side.

    References | Related Articles | Metrics
    Prediction on Ecological Water Demand in the Mainstream of the Tarim River Based on Ecological Restoration
    GUO Bin, WANG Xinping;, LI Yin|LI Huimin, LI Weihong, ZHAO Ruifeng
    2010, 29 (9):  1121-1128.  doi: 10.11820/dlkxjz.2010.09.015
    Abstract ( )   PDF (1404KB) ( )   Save

    In this paper, the ecological water demand in the mainstream of the Tarim River under the current year 2005 was calculated with the quota-area method, the phreatic evaporation method and the groundwater storage quantity change method. The ecological water demands calculated with these methods are 33.89×108 m3, 23.97×108 m3; and 33.07×108 m3;, respectively. In comparison, the reasonable ecological water demand is 30.31×108 m3. Besides, the monthly ecological demand in the mainstream of the Tarim River was acquired on the basis of monthly phreatic evaporation calculated by Aweliyongrufe formula and Qunke formula based on monthly average evaporation (1995-2004) from Aksu, Shaya, Ruche, Luntai, Korla, Yuli and Tikanlik weather stations. Analyzing the monthly ecological water demand, it was found that the ecological water demand in the growing season(from April to October) was 86% of the annual total, with May, June, July and August accpunting for 59% of the annual total. According to the ecological restoration scheme formulated, the ecological water demand of the three target years were forecasted with the quota-area method and the phreatic evaporation method. The reasonable ecological water demand in 2010, 2015 and 2020 are 31.88×108 m3, 34.08×108 m3 and 36.84×108 m3, respectively by averaging the two results. This study provides a scientific basis for optimal allocation of water resources in the Tarim River Basin.

    References | Related Articles | Metrics
    Temporal-spatial Evolution of Stream Construction and Its Driving Forces in Manas River Basin During 1958-2006
    ZING Hongbo, XU Hailiang, QIAO Mug, FAN Zili, SHI Wei, ZHANG Qingqing
    2010, 29 (9):  1129-1136.  doi: 10.11820/dlkxjz.2010.09.016
    Abstract ( )   PDF (1584KB) ( )   Save

    This paper analyzes dynamic changes of length, density, branching ratio, length ratio and fractal dimension of the river networks and their driving factors based on the visual interpretation of remote sensing image of Manas River Basin during 1958, 1976, 1987 and 2006 by using the software of Are/Info. In the results, the changes of the river networks obey Horton’s law, with geometric changes of stream number and average length and with continuous increase of river density, length ratio and branching ratio. River density of oases in the basin is higher than that in the southern mountainous areas and the northern deserts. This is determined by the eeo-environment, social-economic, synconditions, integrated development and ecological restoration in those areas. The increase of water quantity, population, and areas of cultivated lands and oases are the main driving factors. The expansion of cultivated land and oases is limited by water carrying capacity, therefore, it will become the key tasks to make rational plans for oases, to optimize river system structure and to improve water use efficiency.

    References | Related Articles | Metrics
    Estimation of the Surface Vapor Pressure Based on the MODIS Images
    HUANG Yaohuan, JIANG Dong, ZHUANG Dafang, FU Jingying
    2010, 29 (9):  1137-1142.  doi: 10.11820/dlkxjz.2010.09.017
    Abstract ( )   PDF (1011KB) ( )   Save

    Surface vapor pressure (SVP) is a highly significant variable for physically based ecosystem, hydrology and climate modeling without available regional spatially representative data currently. Conventional field observation SVP data is spatial discontinuous and time-consuming, so MODIS images are used to estimate the mean daily SVPin the Haihe River basin. Firstly, correlation analysis is taken and it is found that there are significant correlations between the dataset of precipitable water vapor low in MOD07 images and field observed SVP. Secondly, comparison of the models based on correlation analysis shows that second-order polynomial regression is the most suitable one for evaluating SVP in the Haihe river area. Finally, a series of MOD07 images from January to April of 2009 are used to validate the proposed second-order polynomial model. The result shows that the estimated value is close to the observed value, and their slope and R2 of 1:1 line analysis are 0.918 and 0.83, respectively. The results indicated that the proposed PWV-SVP model is effective for obtaining SVP data at a regional scale.

    References | Related Articles | Metrics
    Remote Sensing of Impervious Surface and Its Applications: A Review
    LIU Zhenhuan, WANG Yanglin, PENG Jian
    2010, 29 (9):  1143-1152.  doi: 10.11820/dlkxjz.2010.09.018
    Abstract ( )   PDF (1279KB) ( )   Save

    Impervious surface can be defined as any materials that prevent the infiltration of water into the soil. Principally, roads and rooftops in the urban are the most prevalent and easily identified types of impervious surfaces. Other types include sidewalks, patios, bedrock outcrops, and compacted soils in the urban areas. Impervious surface not only indicates urbanization, but also is a major contrihutor to the environmental impacts of urbanization. Impervious surface area (ISA) is the index of impervious surface landscape components, which uses the percentage in a pixel for representation. It is an index to monitor the urban ecological system and environmental change, and is an important indicator of the ecological and environmental model, which can affect urban hydrological cycle, surface runoff, water quality, local climate, and biological diversity. This paper reviews the development of remote sensing technology of impervious surface, and summarizes how it impacts urban ecosystem and urban environmental system. From the aspect of remote sensing technology, sub-pixel decomposition including spectral mixture analysis and regression analysis, and other new methods for interpreting image, will be the trend of the application of remote sensing research to urban natural resources and environmental studies in the future. From the aspect of remote sensing data source, the data of medium-resolution (10-100 m) image and high-resolution (0.3-5 m) image, which are used to estimate the index of impervious surface in multi-temporal and large-spatial area, can provide a reliable basis to monitor urban land use/cover change and environmental response. As an environmental indicator, impervious surface area (ISA) can be used to monitor urban land cover change and simulate future urban development, providing a basis for the decision making of urban planning and management. Referring to the fact that impervious surface has an important relation to the hydrological cycle, non-point source pollution, land surface temperature, vegetation variation and biological diversity, if we can understand the relationship between impervious surface area and the environmental or ecological indicators, we(an better understand urban landscape pattern and ecological processes. Impervious surface area plays an important role in studying the eco-environmental effects of urbanization.

    References | Related Articles | Metrics