Archive

  • Select all
    |
    Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    SUN Hong-lie, CHENG Sheng-kui, FENG Zhi-ming
    Download PDF ( )   Knowledge map   Save
    Over the past 60 years, Resources Science has been developed into a comprehensive disciplinary system from integrated surveys of natural resources from the very beginning. Within this period, seven national development plans in science and technology were drawn up successively, among which the Long-Term Scientific and Technological Development Plan (1956-1967) and the National Program Outline for Scientific and Technological Development (1978-1985) had a maximum impact on the making and burgeoning progress of Resources Science. Specifically, the former plan greatly pushed forward the undertaking of comprehensive investigation of natural resources coming into being, while the latter one promoted further achievements of the undertaking, also gave strong impetus to Resources Science to take shape. The trajectory of Resources Science over 60 years could be divided into three main research stages, namely, stage of massive surveys of natural resources (1950-1960s), stage of regional comprehensive scientific investigation and Resources Science research (1970-1980s), and stage of the formation and advancement of Chinese Resources Science disciplinary system (1990-2000s). Three publications of significant landmark that are Chinese Natural Resources Series, China Encyclopedia of Resources Science, and Resources Science coming out around 2000 laid solid foundation for the establishment of Chinese Resources Science disciplinary system. In 2008, the published Chinese Terms in Resource Science and Technology went a step further to boost the development and improvement of Resources Science disciplinary system.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    XIE Gao-di, FENG Zhi-ming, SHEN Lei, HUANG He-qing, LI Li-juan, CHENG Sheng-kui
    Download PDF ( )   Knowledge map   Save
    The tracing and research on the evolution, the exploitation and utilization, and the regulatory mechanism of natural resources has always been an important study task and research orientation in the resources and environment study area of our institute (Institute of Geographic Sciences and Natural Resources Research,CAS). This paper summarized the achievements and progress in the study area of natural resources and environmental security of our institute since 1950.From 1950 to 1978, the prime work of the natural resources and environmental security study area of our institute was the large-scale natural resources investigation and integrated scientific research which has gained achievements. These achievements have provided substantial scientific support for the resources exploitation and regional development in China, and made an indelible contribution in the natural resources research area. Furthermore, they also have played a positive role in the systematic accumulation of scientific material and the emergence of the study in resources sciences. In addition, they have laid the foundation for the understanding of the resources and environment and the establishment of natural resources sciences system. From 1978 to 2000, the study orientation of the resource and environment of our institute has made an important conversion. And during the period, integrated regional resources survey and the studies of resources were simultaneously the two key research areas of our institute. And a series of survey reports that have done during this period of time have defined the direction of regional development and have laid the foundation in data for the fully understanding of the natural resources and the integrated research of natural resources in China. After 2000, firstly, our institute has paid more attention to subject system establishment, which promoted the establishment of the system of resources sciences. Secondly, we have laid more stress on the world resources research, therefore, our natural resources survey fields have extended to the global scale. Thirdly, we paid more attention to the mechanism process research, and provided a new space in the theory of some resource and environment fields, such as the capability of resources and environment, the resources flow, the resources security, and the ecosystem service. Fourthly, we paid more emphasis on the technology of resources exploitation and utilization, and we have made substantial achievement both in theory and technology of environment restoration.As we look to the future, the resources and environment study field in our institute will continue to make the national significant strategic demand as our orientation, and we will make the water resources, land resources, biological resources, energy and mine resources and so on as our main study subjects. In a conclusion, we will conduct systematic research work in the following five aspects in order to push forward the establishment and development of the subject of resources: 1) integrated regional scientific investigation and integrated study of resources sciences; 2) the sustainable utilization of land and water resources and its complexity; 3) the flow process of natural resources and its eco-environmental effects; 4) the status of world-wide resources and the national strategic resources security; and 5) the environment restoration mechanism and the renewal and utilization of wastes.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    DONG Suo-cheng, SHI Guang-yi, SHEN Lei, WANG Li-mao, YANG Wang-zhou
    Download PDF ( )   Knowledge map   Save
    Natural resources are the material basis for human survival and development. Resource shortage is an important limiting factor of social and economic development in China, which will be more prominent in the future. Resource economics is a comprehensive discipline to research the relationship between economic development and resource exploitation, utilization, protection, distribution and management. It has important strategic significance for realization of sustainable development to strengthen research of resources economy and world resources. To meet the needs of national development, the research fields of domestic resources and resources science have been made significant progress in China. World resources have been actively concerned and researched, and great achievements have been made in world resources research. These researches put forward new demands, accumulated abundant research data, practical experience, research methods and systemic theory preparation for development of resource economics, which promote continuously resources economic research and growth and development of resource economics discipline, and make an important contribution to national development. This paper focuses on research progress of resource economics and world resources, to summarize and evaluate the progress and achievements of research on resource economy and world resource, in addition, to prospect on the research trend of resource economy and world resource in China, and present research direction and key research fields of that in the new period.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    JIA Shao-feng, FENG Zhi-ming, LI Li-juan, HUANG He-qing, YAO Zhi-jun, GAO Yan-chun, JIANG Lu-guang
    Download PDF ( )   Knowledge map   Save
    Resource geography and water & land resources are important fields of natural resources research. The Institute of Geographic Sciences and Natural Resources Research, CAS, is one of the main institutes of resource geography and water & land resources research, as well as the former Institute of Geography and Commission for Integrated Survey of Natural Resources, CAS and State Planning Commission. Thanks to the hard work and dedication of several generations of scientists, great achievements have been gained during the last 70 years. On the occasion of the 70th anniversary of the foundation of the institute and 55th anniversary of integrated survey of natural resources, the related research results of resource geography and water & land resources are briefly introduced and the trends of future development in related fields are proposed.
  • Special Column:Celebration of the 70th Anniversary of IGSNRR, CAS
    WANG Hui-min, YANG Feng-ting, LI Qing-kang, MA Ze-qing, CHENG Tong
    Download PDF ( )   Knowledge map   Save
    Since the 1980s, researchers from Integrated Scientific Survey Team of Chinese Academy of Sciences in Southern China Mountainous Region and Qianyanzhou Ecological Station, Chinese Academy of Sciences, have done a lot of study on the comprehensive scientific investigation of natural resources, the demonstration of agricultural science and technologic development, and the application of fundamental theories. Outstanding contributions have been made to the ecological restoration and sustainable development of economy in red soil hilly regions. New progress has been made in material cycling mechanism and its responses to global climate change. Based on the main structure thread of the development of Qianyanzhou Station, this paper reviews on the achievements and development of the eco-environment study in red earth hilly region of southern China.
  • LIU Hai-long, PAN Yun-wei
    Download PDF ( )   Knowledge map   Save
    At present, the spatial systems of geoparks of China are formed basing on official declaration systems from bottom-up process. Thus there exist several problems, such as the illogical distribution and the insufficient scientific foundation of the category system. Therefore the evaluation and guidance for their representative, proportionality, and reliability from macro scale are weak. After the introduction of the world trend to establish the conservation network of natural heritage, this paper summarizes some factors that play important role for the spatial distribution of geoparks of China: from their relevance with natural geographical patterns, geological zones and administration divisions, to the resource investigation, overlap of various nature reserves, the social-economic influences and the political recognition, etc. Finally it puts forward some suggestions to improve the efficiency of conservation network of geological sites of China: stress on the top-down evaluation and guidance that are complementary of the bottom-up declaration process; reinforce geological resource investigation and find the conservation gap; toward the network conservation model; establish the cooperative administration platforms for multilevel geo-network.
  • Resources Utilization and Management
  • Resources Utilization and Management
    LIANG Xiao-ying, LIU Jun-xin
    Download PDF ( )   Knowledge map   Save
    It is important to discuss the mechanism between the household land use behavior and the agriculture landscape pattern. This research is helpful to understand the transition of the household behavior, and comprehend the evolution process and characteristics of the landscape pattern. Making use of the cadastral data and parcel area of 2007 and 2008 of the Mengcha village, this paper uses the household land use decision-making mode and the weight-influence mode to research the relationship between the dominant land use decision-making and the dominant landscape pattern. From our study and analysis, a number of observations and conclusions can be drawn on the implementation: 1) the dominant land use decision-making must not produce the dominant landscape pattern by this land use decision type; and 2) The whole household dominant land use decision-making in this year must not produce the dominant landscape pattern by this land use decision type in the next year. Our future research work will focus on the following aspects: 1) in order to improve the individual land use decision-making mode, the mode should involve the risk adverse factor, the crop rotation factor and the special land use type transition rule factor; and 2) it is necessary to research the integrated method which consider the land use parcel area and the individual land use decision-making comprehensively.
  • Resources Utilization and Management
    CHEN Yu-qi, LI Xiu-bin, SHENG Yan, ZHANG Wen
    Download PDF ( )   Knowledge map   Save
    Influenced by increasing thirst for energy to fuel fast growing economy and pressure of reducing greenhouse gas emissions, biofuel production expanded rapidly these years. The total bio-ethanol production increased from 5.68×108 L in 1975 to 170×108 L in 2000 and to 511×108 L in 2007. The biodiesel increased from 9.1×108 L in 2000 to 132×108 L in 2007. The rapid increase of biofuel aroused hot debates on its effect on food security. This paper analyzed the debates of biofuel production, area of land used for biofuel production, its impact on land use changes and the international mechanism of farmers’ land use decisions. Results show that as one of the main input of biofuel production, land use change is the medium of its influence on food security, environment and other social dimensions. Secondly, the arable land used for biofuel production has been increased rapidly these years. In 2004, there was 1400×104hm2 of arable land used for biofuel production, accounted for 1% of the total arable land (140583×104hm2). In 2007, figure increased to 4221.7×104hm2. It is projected that fuel crops’ sown area may account for 15%-20% of the total sown area in some countries in the near future. Fuel crops will become one of the main crops. Thirdly, extension of the sown area of fuel crops caused remarkable land use changes. Large area of forest, grassland and unused land was converted to agricultural land. In the internal planting structure, food crops were converted into fuel crops. Fourthly, household is the basic decision maker of land use changes. Attracted by higher income, famers are more inclined to plant crops that have more net income. From the input-output comparison of main food and fuel crops in Guangxi, net income of fuel crops is much higher than food crops. In 2009, the net income of cassava was 11123.04 yuan/hm2 and sugarcane 12138.36 yuan/hm2, more than rice (6984.04 yuan/hm2), maize (5104.61 yuan/hm2) and peanut (2851.36 yuan/hm2). This is the basic reason for the increase sown area of fuel crops. Finally, the paper proposed that further studies were needed to be done on the quantitative analysis of the competition of biofuel crops and food crops, the internal mechanism of farmers’ land use decisions, the impact of biofuel production on future land use changes in the process of urbanization.
  • Resources Utilization and Management
    JIN Cheng, FAN Li-li, LU Yu-qi
    Download PDF ( )   Knowledge map   Save
    Taking the agricultural tourism demonstration sites as the research objects, this article discusses the spatial distribution status quo of agricultural tourism in Jiangsu Province from the perspective of accessibility.The accessibility of agricultural tourism destination sites is well, and the regional average accessibility is about 26.50 minutes, and the area where accessibility of scenic spots within 30 minutes reaches 64.53%, less than 5% of the regions over 1 hour.The article studies the spatial development between agricultural tourism demonstration sites and cities nearby. In Jiangsu Province, there are 124 agricultural tourism destination sites, among them the time of the shortest distance between the sites and the city nearby is 2.45 minutes and the longest is 65.58 minutes, and the average is 20.68 minutes.Viewing from the two-pronged approaches of economy and population to explore the development potential of each city’s agricultural tourism situation, five categories can be divided. The highest potential region is mainly distributed in Nanjing downtown area and Wuxi downtown area, and the higher potential region is mainly distributed in Suzhou downtown area, Changzhou downtown area, Jiangyin downtown area and Xuzhou downtown area.Finally, from the distance away from the city and the development potential of agricultural tourism in county units, Jiangsu Province, according to whether or not suitable for agricultural tourism, four types are divided, namely: highest-suitable areas, higher comfort areas, moderately suitable areas and low-fit area. Among them, the highest-suitable areas for the agricultural tourism are mainly concentrated in two areas: Nanjing outer suburbs and Su-Xi-Chang Region. The higher comfort areas are mainly located in Kunshan, Changshu, Zhangjiagang, Jiangyin and the northern part of Xuzhou city.
  • Resources Utilization and Management
    TIAN Li-xin, LIU Jing
    Download PDF ( )   Knowledge map   Save
    In this paper, using the Solow production function model, the relationship between energy prices and energy intensity is constructed. Then we use the 1990-2008 time series data of the national and Jiangsu Province to assess the impacts of the relative price of energy to energy intensity. We put the technological progress containing time parameter as a single parameter to consider. The results show that, in recent years, the decline in energy intensity of Jiangsu Province is obvious. However, the rise of the relative price of aggregate energy in Jiangsu Province for the reduction of energy intensity is not optimistic, the rise of the price of electricity has a certain role in it.
  • Resources Safety
  • Resources Safety
    WANG Qian, JIN Xiao-bin, AYITUERXUN Shamuxi, ZHOU Yin-kang
    Download PDF ( )   Knowledge map   Save
    In order to reveal the spatial distribution pattern of food production in Hebei Province, and formulate regional development of food safety policy suitable to local conditions, this paper using the Exploratory Spatial Data Analysis (ESDA) combined with GIS spatial analytical technology and structured spatial adjacent matrix, analyzed spatio-temporal changes and regulations in grain production of 138 counties in Hebei Province of China from 1986 to 2006. Research showed that grain production presented aggregated global spatial patterns at provincial level with an average Moran’s I index of 0.346. Grain yield shows significant local spatial clustering pattern, distributing mainly in the Tangshan-Shijiazhuang piedmont high-yield area (HH) and the Zhangjiakou-Bashang Plateau and Chengde low-producing areas (LL). Counties fell into the quadrant of the HH and LL accounted for 55.07%, 66.67% and 71.74% of the total sample size in 1986, 1996 and 2006, respectively. Grain production has a strong spatial correlation, a significant pattern of local clustering, and aggregation in the study phase, as well as continuous enhancement in the local context in Hebei Province; but it also reflects the spatial heterogeneity in distribution of grain yield, showing the local distribution pattern of discrete and the weakening degree of dispersion. The study also revealed, through the average center model, the focus of grain production has shifted 42.7 km to the north-southwest direction in the region. The dialectical relationship between economic development and intensive land use is the main reason for the focus transfer of rain production. Grain production in Hebei Province is divided into climate yield and economic yield, correlation analysis showed that input factors affecting grain production from 1986 to 2006 are diversified. The main factors which affected food production are the effective irrigated area, fertilizer application rate, the total power of farm machinery, grain sown area and so on. Finally, policies and measures of regional food safety were proposed, based on space difference research of the grain production.
  • Resources Ecology
  • Resources Ecology
    ZHOU Bin, JIANG You-xu, ZANG Run-guo
    Download PDF ( )   Knowledge map   Save
    The natural forests (NFs) play a more important role than planted forests in ecological services. The NFs resource is one of the important indicators for characterizing local ecological environment status. Dynamics analysis of NFs resources is beneficial to the improvement of management efficiency and promotion of local sustainable development. We analyzed the NFs data extracted from forests inventory reports published by government since 1949. The results showed that the development of NFs could be divided into two phases over the past 60 years: wood consumption and ecological restoration. In the first 30 years, the NFs area and volume declined by 26% and 33% respectively because of timber harvest, whereas they continually recovered under ecological environment construction in the latter 30 years. The NFs area reached the top point of 25.87 million hm2 in 2008 and its stands volume of 3.2 billion m3 was close to the figure of 1949, especially with the remarkable promotion of Natural Forest Protection Program (NFPP) since 1999. But the quality of overall NFs improved slowly and 123 m3 per hm2 was still at the low level in 2008. And the age structure of NFs was unbalanced. Forests volume of young and middle NFs was not increased rapidly with its area, its area accounted for 58%, but its volume only 30%. At present the ratio of commercial forests area to ecological ones was almost 7 ∶3 resulted from the increase of shelter forests and decrease of timber forests since the 1980s. The amount of commercial timber harvested dropped sharply after the implementation of NFPP, but it resumed gradually since 2001 and reached the peak of 9.46 million m3 in 2008. The increasing trend of commercial timber logging amount was not changed over the past 60 years. Based on these dynamic analysis results, considering the future development strategies of NFs in Southwest China, we suggest establishing red line to control the NFs areas, adjusting age structure of commercial forests, shifting NFs area expansion to improve forests quality, strictly controlling the logging of NFs and strengthening ecological restoration of degraded NFs.
  • Resources Ecology
    ZHAO Ming-fei, LIU Quan-ru, KANG Mu-yi, JIANG Yuan, MENG Shi-yong, WANG Jing-lan
    Download PDF ( )   Knowledge map   Save
    Dongjiang River is one of the main inputs of Pearl River water system. Dongjiang Valley is one of the most developed areas of China, which supplies water for Hong Kong, Guangzhou, Shenzhen and other major cities. Based on the 90 quadrats data obtained from field investigation and using quantitative methods of TWINSPAN, DCA and CCA, the types and distribution pattern of plant communities along the riparian zone of the mainstream of Dongjiang River were studied in this paper to reveal the relationship between the communities and their habitats influenced by river section features. 271 species occurring in the 90 quadrats, belonging to 187 genera of 56 families, were recorded in the community investigation. Those 90 quadrats were classified into 15 associations by TWINSPAN according to the community characteristics in species composition and implied habitat differentiation. The first two axes of DCA explained 15.8% of cumulative variation. The first two axes of CCA explained 62.6% of cumulative variation of species-environment relation. The results of both DCA and CCA analyses revealed the distribution of the communities along Dongjiang upper reach, middle reach and lower reach sections with some special habitat features, showing strong influences of environmental factors on fostering the community distribution pattern. Those factors contributed to the formation of the community distribution pattern are mainly temperature, human disturbance and soil water regime.
  • Resources Ecology
    NIE Rui, ZHANG Tao, WANG Di
    Download PDF ( )   Knowledge map   Save
    Mid- and long-term economic growth, energy demand and carbon emissions scenarios in Jiangsu were analyzed using the IPAT model. The main parameters and results for three scenarios are introduced, according to the current energy usage situation and environmental policy. Research results show that low carbon scenario was the most appropriate and realistic way to build the energy saving and environment-friendly society; the targets of energy-saving and carbon reduction will be reached at the expense of the economic growth; with the rapid development of economy in the future, energy demand and carbon emissions will also increase quickly; compared with 2007, energy demand may increase by 1.431 times in 2030, and the carbon emissions may increase to 156.55 million tons; and energy supply and rational utilization will be the bottleneck factors in the future 20 years. Then, several suggestions are put forward in order to deal with the pressure on the reduction of carbon emissions.
  • Resources Evaluation
  • Resources Evaluation
    ZHU Fu-biao, LU Lin
    Download PDF ( )   Knowledge map   Save
    Metropolitan area is one of the most important regions for tourism development; the study of metropolitan area tourism development is very significant. The purpose of this paper is to investigate the spatial tourism equilibrium development of the Pearl River Delta metropolitan area since 1990 and explore its development mechanism. Using methods of location quotient with selecting five time sections, the result shows that: the number of cities with location quotient more than or equal to 1 is increasing. The average percentage of tourism revenue and tourist number of cities with location quotient more than or equal to 1 of the whole metropolitan area is 19.76% in 2000, and then decreases to 12.83% in 2008. It shows that the Pearl River Delta metropolitan area tourism development tends to be equilibrium; spatial tourism equilibrium development is strengthened over time, although there is difference between inbound tourism and domestic tourism, or between tourism revenue and tourist number. In fact, the tendency of the Pearl River Delta metropolitan area spatial tourism equilibrium development is a fluctuated process. Using methods of the hierarchical clustering and selecting related statistical data in 2007 to inspect situation of tourism spatial development, it is found that there are three levels of cities in the Pearl River Delta metropolitan area; Guangzhou and Shenzhen are at the first level, Zhuhai and Dongguan are at the second level and Foshan, Huizhou, Jiangmen, Zhongshan and Zhaoqing are at the third level. Finally, by using the spatial interaction theory, this paper explores the mechanism of spatial tourism proportional development of the Pearl River Delta metropolitan area based on the principal of complementarity, accessibility and alternativity. The conditions of spatial interaction are improved, which strengthen the spatial tourism interaction of all cities in the Pearl River Delta metropolitan area and their relationship with tourism development. Although the spatial tourism equilibrium development of the Pearl River Delta metropolitan area depends on many internal and external environments, the strong spatial interaction influences the development of tourism destination and choices of tourists, and makes the tourism development throughout the Pearl River Delta metropolitan area to be equilibrium.
  • Resources Evaluation
    DENG Chu-xiong, XIE Bing-geng, WU Yong-xing, LI Xiao-qing, FU Li-hua
    Download PDF ( )   Knowledge map   Save
    Based on the existing research achievements at home and abroad, the author built a set of evaluation index system that can highlight the characteristics of urban agricultural sustainable development, and used the method of combination analytic hierarchy process and information entropy method as a core method to determine the index weight, made a quantitative & comprehensive appraisal of urban agricultural sustainable development in Shanghai from the time-series after 1993. The result showed: 1)The population subsystem became a main obstructive factor of urban agricultural sustainable development step by step; the economic subsystem became main contributing factor of urban agricultural sustainable development little by little; the social subsystem was more and more important to promote capability of urban agricultural sustainable development; the amount of cultivated land resources became shortage and continued to decrease, restricting the improvement of capability of urban agricultural sustainable development; heavy load of self-pollution of agricultural production took the negative effects on the overall upgrade of urban agricultural sustainable development capability. 2)The R-D comprehensive index value of urban agricultural sustainable development was not high and declined significantly, its average value was 1.9090 during the period 1993 to 2006, the R-D comprehensive index value decreased by 6.00% per annum from 2.5336 in 1993 to 0.5541 in 2006, resources pressure of urban agricultural sustainable development was greater and continued to increase; the E-D comprehensive index value of urban agricultural sustainable development was smaller and changed little, basically maintained at 1.0000 around most of the years, environmental pressure of urban agricultural sustainable development was great, but tended to be stable. 3)The comprehensive evaluation index value of urban agricultural sustainable development was in the sustainable and steady climb after the pre-wave-like changes, the increasing trend of urban agricultural sustainable development capability was significant.
  • Resources Evaluation
    LI Cui-mei, WANG Jian-hua, WANG Hao, QIN Da-yong, LIU Sui-qing
    Download PDF ( )   Knowledge map   Save
    This paper described the principle of GMM Methods and studied the parameter estimation of urban water price forecasting mathematical model on long-term marginal cost using the GMM estimation methods. By the parameter estimation for water user number, water consumption, water structure, water supply variable costs and water supply fixed costs, it aims to achieve the long-term marginal cost forecasting of water price by taking Suzhou City as a case. The results showed that by application of GMM sample estimation, the demand of a large amount of data required for mathematical model was resolved and the long-term marginal cost of water price forecasting model’s practicality was improved.
  • Resources Research Methods
  • Resources Research Methods
    ZHANG Fang-min, JU Wei-min, CHEN Jing-ming, WANG Shao-qiang, YU Gui-rui, LI Ying-nian, HAN Shi-jie, J.ASANUMA
    Download PDF ( )   Knowledge map   Save
    East Asia is one of the most complicated and disputed areas of carbon and water cycles due to the integrated effect of variable climate and intense human disturbances. Evapotranspiration (ET) is an important component of the carbon-water cycle; however, regional studies of ET in East Asia are still few. This study is to analyze the spatio-temporal distributions of ET in East Asia during 1982 to 2006 using the process-based ecological model BEPS, which was driven by meteorological, soil and remote sensing data at an 8-km resolution. Prior to the regional simulation, BEPS was validated using measured ET in six typical forest ecosystems. BEPS can explain 81.23% of the annual ET and 86.4% of the 10-day ET variations, respectively, indicating that BEPS can accurately simulate ET in East Asia. Simulated annual ET in East Asia shows a gradually decreasing pattern from the southeast and northeast regions to the northwest and southwest desert areas, with the smallest values in the northwestern desert region of China. It also shows that the ratio of ET and precipitation was increasing from the southeast and northeast regions with an average of 0.4 to the northwest and southwest desert region with the values greater than 1.0. The annual total ET in East Asia averaged from 1982 to 2006 was 12045 ×109 m3/a, and China, Pan Southeast Asia and India accounted for 62.4% of the annual total ET. Mean ET per unit area of the study area was 401 mm/a, with the largest values in Pan Southeast Asia (1100 mm/a), and the smallest values in Mongolia (134 mm/a). Relative to the different land cover types, the maximum of the total and mean ET values were the evergreen broad-leaved forests, while the minimum values were both in urban and built-up areas. The whole East Asia region showed a significant increasing trend in ET. Grasslands, savannas, bare land and urban land marked a noticeable increasing trend of ET, yet other vegetation types did not change significantly.
  • Resources Research Methods
    HOU Guang-lei, ZHANG Hong-yan, WANG Ye-qiao, ZHANG Zheng-xiang
    Download PDF ( )   Knowledge map   Save
    As one of the most important agricultural resources, the cropland is the basic survival condition for human being. Accurate information on cropland area is of critical importance for assessing food security. The Northeast China includes provinces of Liaoning, Jilin, Heilongjiang and eastern part of Inner Mongolia Autonomous Region. It is one of the most important marketable production bases and output regions with rich water resources, fertile soil and vast cultivated land. With the unprecedented combination of economic and population growth, a dramatic land transformation has caused across this region, and the cropland degradation is increasingly serious. In order to preserve and manage cropland resources, it is essential to investigate and monitor cropland dynamics. Compared to traditional observations in the field, the principal advantage of remote sensing data is the possibility that they offer to gather synoptic information at regular time intervals over large areas. Especially for the muti-temporal images, repeated observations can be used to monitor characteristics of phonological dynamics at regional level. The normalized difference vegetation index (NDVI) which derived from the remote sensed data, is one of the most important parameters for the vegetation growth and was widely used in the land cover classification. In recent years, with the development of the theory about Artificial Neural Network (ANN) system, the neural network technology is becoming increasingly an effective means of classification processing of remote sensor digital images. Therefore, on the basis of the muti-period NDVI, the cropland can be identified and separated from the other land cover types by means of the neural network technology.In this paper, Harmonic Analysis of a Time Series of SPOT/VGT NDVI data was used to develop an innovative technique for cropland identification in Northeast China based on temporal variations of NDVI values during 2007. Different vegetation classes (forest, cropland, grassland, water body) exhibiting distinctive seasonal patterns of NDVI variation have strong periodic characteristics. A Discrete Fourier Filter was applied to NDVI time-series data in order to minimize the influence of high-frequency noise on class assignment. Because of the different phonology and periodicity in various land use types, the amplitude, phase and annual NDVI mean value in the studying area are acquired and integrated for an image. According to the training sample size, the neural network classification measure is introduced to extract cropland. The total accuracy is 83.26% while Kappa coefficient is 0.7324. The accuracy of measurement to extract cropland information is much higher by comparing the four current products (GLC2000 land cover data, UMD land cover data, IGBP land cover data and CAS land cover data). The study indicates that it is feasible for cropland extraction utilization of time-series analysis and neural network classification, and can provide accurate, scientific cropland information for agricultural administrators and land management decision making.
  • Special Forum
  • Special Forum
    HAO Ze-jia, WANG Ying, CHEN Yuan-sheng, JIANG Lei, YIN Chun-ting
    Download PDF ( )   Knowledge map   Save
    Water saving is an effective way to ease water shortage. At the same time it relates to the complex situation of cognition and awareness on social psychology. Questionnaire surveyed 312 high school students in Beijing is designed to evaluate their present situation of water saving knowledge, awareness and behavior. Further, a systematical analysis on the interrelation between water saving knowledge, awareness and behavior has been conducted in order to provide scientific support to establish more effective water management measures. The result shows reliability index (Cronbach’s α) values of water saving knowledge, awareness and behavior scales are 0.82, 0.77 and 0.84 respectively. Advanced analysis finds out high school students are generally lack of exact quantitative cognition of water conservation. Consequently, they are not able to figure out the reasonable degree of water use. And TV is the main source of their obtaining such knowledge. To a certain degree, high school students are sensitive and have sense of response to water scarcity as it has been widely recognized. Although they can perceive changes of water resource condition, water conservation is still like a slogan rather than deep understanding. As a result, those students need improvement of their water saving behavior. Comparing changing one’s own water use behavior and others’, the analysis shows the frequency of the former is over a half while the latter occurs very rare. Water saving awareness is significantly impacting water saving behavior. But it turns out that water saving knowledge has no statistical significance to water saving awareness. Meanwhile, water saving knowledge is proved to have direct impact on water saving behavior, and through water awareness it produced a mediator effect which can also impact water saving behavior. Proportion of both impacting effects of knowledge is 9 ∶1.