A catchment- scale distributed hydrological model is developed for coupled simulation of surface and subsurface runoffs. Interactions between surface runoff, soil water and groundwater are realistically simulated. In particular, characteristics of the lake - catchment system are considered in the model so that the model is more flexible to be applicable to lake catchments than other existing models. The model can simulate multiple river sub- catchments within a lake catchment, as well as direct overland flow and subsurface flow into the lake. Preliminary model application was undertaken in Fuxianhu Lake catchment, Yunnan Province, China. Comparison of predicted results with the observed ones in terms of stream flow, soil water content and groundwater level demonstrates a satisfactory agreement. The modelled results are also compared with those from the SCS model to further validate the model. The model can be used to investigate various hydrological processes of the lake - catchment system, to simulate the response of catchment hydrological processes to the change of natural conditions or human activities, and to explore the interactions between surface runoff, groundwater and lake. The model would also be a useful tool for water balance analysis of the lake - catchment system to facilitate water resources management.
Efforts to improve the knowledge on the human dimensions of global environmental change and ensure relevance to society require periodical assessment of the conceptual frameworks used in the study of these complex issues. As one of the four cross- cutting themes of IHDP, resilience, vulnerability and adaptation are three key concepts in the research of the Human Dimensions of Global Environmental Change. However, these concepts are widely used in many fields, such as, economy, engineering, psychology and anthropology. For different research traditions these terms are used in different, sometimes incompatible, ways. In order to clarify the three key concepts, the Scientific Committee of IHDP organized a workshop in February 2005. A series of articles that resulted from the IHDP workshop were published on the journal of Global Environmental Change Issue No. 16 2006. Based on the above articles and the researches of UNU, this paper reviews research traditions of resilience, vulnerability and adaptation respectively, with focus on the current researches on the conceptual relations among these core concepts as cross- cutting themes in the field of global environmental change and disaster riskreduction.
Using the temporal wavelet transform method for three- dimensional data , the temporal- spatial features and law of summer precipitation interannual variability over the Longitudinal Range- Gorge Region (LRGR) under effect of the summer monsoon are investigated. The results show that there are 2- year, 7- year and 16- year characteristic timescales for the summer precipitation interannual variability over the LRGR under the effect of the summer monsoon. The larger amplitude energy regions corresponding to the 2 - year, 7 - year and 16 - year characteristic timescales are consistent with or normal to the mountain ranges of LRGR respectively. The summer precipitation longitudinal evolutions of the larger central latitude in association with the 2- year characteristic timescale show obviously longitudinal oscillations. But the summer precipitation longitudinal evolutions of the larger central latitudes in association with the 7- year and 16- year characteristic timescales have obviously the tendency to move towards the west and the east respectively. The summer precipitation latitudinal evolutions of the larger central longitude in association with the 2- year characteristic timescale also show obviously latitudinal oscillations. But the summer precipitation latitudinal evolutions of the larger central longitudes in association with the 7- year and 16- year characteristic timescales have obviously the tendency to move towards the north and the south respectively.
The United Nations International Decade for Natural Disaster Reduction (IDNDR) gives rise to an increasing level of attention to the risks posed by a range of natural hazards and the development of strategies by which to reduce those risks. After many years of development, risk assessment of storm surge becomes a distinctive study field and an important part of risk management of storm surge. At present, more focus has been put on the numerical prediction of storm surge, the estimation of the height of storm surge and return period, the assessment of the hazard impact and the exposure and the vulnerability of the hazard- affected bodies, the regionalization of the natural disaster risk and the assessment of disaster losses, instead of the study of the comprehensive risk assessment of storm surge in coastal cities and the consequential disaster chain. Forming a indicator system for the risk assessment on the point of nature, society, economy and so on and making a comprehensive storm surge risk research based on 3S are an important field of storm surge study. This paper points out that the future study should be to develop scenario- based methodologies for storm surge risk assessment and the auxiliary risk- based decision supporting systems, to enhance compilation of the map of retreat and to set up sustained disaster risk management system in metropolises. The quantitative assessment of disaster prevention programs and disaster losses should also be stressed.
This paper focuses on the upper Chao Watershed, which is the important water source for Beijing and 40% of the upper Miyun Reservoir Catchment, aiming at the analysis of the changes of rainfall - runoff relationship from 1961 to 2005 and the impacts of human activities (especially ecological construction projects, e.g. planting trees) upon the rainfall- runoff relationship. By drawing a double mass curve of rainfall and stream flow data from 1961 - 2005, 3 periods could be divided: 1961 ~1978, 1979 ~1993 and 1994 ~2005. The correlation between rainfall and stream flow kept weaken, as well as average annual stream flow kept reducing from period I to period II and III. Corresponding with the changes of rainfall- runoff relationship, the human activities in this watershed became more and more intense. In period II, most of the irrigation works and water conservancy establishments were built and applied, at the same time, the areas of forest and cultivated land increased by 7.8% and 7.5% respectively under the impacts of land use activities. In period III, forest lands increased by 11.8% as the results of afforestation and reafforestation aiming at water and soil conservancy. All kinds of human activities results in the weakened response of stream flow to rainfall and the reduced water yield. In different rainfall type years, the rainfall - runoff relationships have shown much difference. Comparing to high - rainfall years, the human activities exerted more influence on rainfall- runoff relationship in low- rainfall years.
Taking Beijing Municipality as a case study area, this paper tracks changes of greenspace patterns by analyzing the data of land use. Green- space is very important for planning overall nature and human being in the development of cities. The study analyses the changes of green - space areas and structure divisionally from 1992 to 2004. Applying spatial analytical methods in GIS, the green- space information is picked up from the map of land use survey in 1996 and 2004. By way of the information entropy of green- space in Beijing in 1996 and 2004, we can find the changes of green space area and structure. The objective of this study is to find the character of changes of green- space patterns and its influencing factors. We attempt to put forward the scientific gist for environmental construction in Beijing.
Landscape sensitivity is expressed as the ratio of the change in landscape to the change in a landscape component. The larger the ratio is, the greater the sensitivity is. We reviews and analyzes the definition of landscape sensitivity, and we also discuss the key factors which determine the sensitivity of landscape and the spatial- temporal sensitivity. Furthermore, we point out that the key factors which determine the magnitude of landscape sensitivity are the types of disturbance and the attributes of the landscape. There are two kinds of disturbances: pulsed and ramped. The attributes of landscape mean the trend of landscape change and the resistance forces to the disturbances. We also summarize the means of spatial sensitivity and temporal sensitivity. Spatial sensitivity is expressed as locational sensitivity or the location where is the landscape changed. And temporal sensitivity is the impacts of changes in the magnitude and frequency of events on the landscape. Landscape sensitivity, which describes a nonlinear dynamic system and its responses and resistances to changes, will help us get more understanding of the landscape changes.
The synthesis evaluation of intensive land use and growth pattern transformation of towns is very important means for exalting the land - use management level, enhancing the intensive land use efficiency in maximum, and insuring the sustainable development. According to such six principles as scientific、comparable、mezzo、delaminating、impartial and objective - oriented, considering comprehensively economic, social and ecological benefits of intensive land use, this paper constructed the synthesis evaluation index system of intensive land use and growth pattern transformation of towns, from the angle of growth pattern transformation. In order to give the weighted coefficient values of evaluation index, it used the AHP models based on entropy technique as well as methods about transforming qualitative index to quantitative index based on expert opinions; and quantified the positive and subtractive index respectively by means of fuzzy membership functions; then, based on the synthesis evaluation index system, it constructed a multi- layer, multi- objective fuzzy comprehensive evaluation model to assess the synthetical level of intensive land use. At the end, this paper applied this method in the synthesis evaluation of intensive land use and growth pattern transformation of towns in the North New Area of Haidian in Beijing. Results show that, the intensive land use level of towns in the North New Area is low as a whole, and the index of resource utilization and environment amity is lower. So, for the future, we should transform the growth pattern more and improve the level of intensive land use in towns of the North New Area.
Suspended sediment dynamics are still imperfectly understood, especially in loess hilly region on the Loess Plateau with strong temporal variability, where few studies heretofore have been conducted. Using the dataset up to eight- year long in the Lower Chabagou Creek, the variability in suspended sediment load at different temporal scales (within - flood variability, monthly- seasonal and annual) were analyzed in this paper. The results show that, within- flood scale, most of the sediment peaks lag behind peak discharges independent of the occurring sequences of the peaks of sediment and discharge, all the events could present anti- clockwise hysteresis loop resulting from the influence of hyperconcentrated flows on suspended sediment concentration. At monthly and seasonal scales, there is a “store- release ”process, i.e. sediment is prepared in winter, spring and late autumn, and exported out in summer and early autumn. At the annual scale, the high- variability in concentration and sediment yield are highly correlated with water yield, resulting from the number and magnitude of floods recorded yearly, since almost all the suspended load is transported during these events.
The urban agglomeration is a high- quality spatial organization form of cities in urbanization advancement. When entering into the 21st century, urban agglomeration is becoming the main body shape of Chinese urbanization, the important carrier of the national economy and the national synthesis competitive power. And it manifests an important tendency in the urbanregion development. Yet, many urban agglomerations still are at the separate “planning agglomeration ”, and have not formed the strength region entity with competitive power supported by city cluster. And the region coordination mechanism has fundamentally not established. In order to solve this serious problem in urban agglomeration development, we must take the integration development path; therefore, the integration development is an important issue for the urban agglomeration strategy. The integration development of the urban agglomeration must set up the correct scientific ideas, and absorb fully the precious enlightenment of the domestic and foreign correlation researches. The core theory of the integration development includes the competitive advantage theory, the spatial interaction theory. The spatial development theory and the region coordination theory. The basic theory includes the system theory, modern economy growth theory, sustainable development theory and region innovation theory. The existence of the urban agglomeration is the first realistic foundation for the integration development, including the existence condition evolution and the vast existence value of the urban agglomeration. The essential factor of the urban agglomeration is the second realistic foundation for the integration development, including the resource endowments, the overall strength, the industrial structure, the transportation- correspondence, and its core city. The urbanization in urban agglomeration area is the third realistic foundation for the integration development, including the comprehensive urbanization level and the main problems in urbanization advancement. The practice of the integration development contains 6 aspects: city competitive power integration, urban system integration, industry integration, space integration, urban- rural ecological environment integration, and developing support platform integration.
Accessibility is a research topic in the field of geography, civil engineering and transportation economics. Currently, a range of accessibility measurement approaches have been widely used in transportation network and urban development planning, transportation infrastructure effects evaluation on regional economy, location- allocation researches, landscape planning, social culture researches, to name a few. With rapid increasing of application demands and unceasing development of technology researches, accessibility measurement approaches also develop swiftly and the methodology is being formed. Based on a comprehensive exposition of accessibility concept, this paper systematically discusses the state - of- arts of accessibility measurement approaches, carries out a classification of these approaches from the perspective of network characteristics, and comparably elaborates and evaluates these approaches according to their influencing factors. Then application of various approaches are discoursed and analyzed in detail, consistent with different application areas. Finally the research priorities of accessibility research are thoroughly discussed.
The process of city' s development is also a process of the culture creating and coming together. It influences the mankind' s quality of life deeply. Therefore examining the phenomenon of urbanization from the culture, we can know the essence of urbanization systematically. This article investigates the present condition of urban cultural characteristic in Dalian, analyzes the cultural differentiation of the city area and suburban area in the process of fast urbanization by means of GIS, and studies such differentiation' s space characteristic, space regulation and its cause of formation. The results from the present investigation suggest that the reality of the urban culture development in Dalian has obvious spatial differentiation. The east central and the south parts enjoy a higher degree of urban culture development, but the west and the north parts are lower.
As a scientific infrastructure, scientific data sharing platform can promote primitive innovation of science and technology, and improve national scientific and technological competitiveness. This paper reviews the initiatives aiming at promoting China' s scientific data sharing activities in recent years, indicates major problems in the process of its implementation, and explores the focal point of future progress and working method of scientific data sharing in aspects of ideas, data integration, and platform building. Taking the practice of Data Sharing Network of Earth System Science (DSNESS) as an example, the paper examines scientific data sharing alliances; implementation of initiative service; combination of scientific research and data sharing activities; data agents; powerful scientific data search engine; promotion of document and information services, and etc. As a result, DSNESS has integrated about 7TB scientific data and established one head- center, one authentication- center and 12 sub- centers that form a distributed data sharing network platform. Through this platform, we have provided different data sharing services for more than 20,000 users.
