As the transition region of two kinds of completely different ecosystems, the urban fringe is one of the areas where land use/cover changes most fiercely. The situation of land use in urban fringe area has been paid more attention to by people day by day. Taking Wuxi City as an example, this paper utilized 3S technology to extract information of land use/cover condition in urban fringe. Considering both region structure model of fringe area as the theoretical foundation and building density as the standard, this study regarded the edge of the built-up area of the city as the border distinguishing area with the city and fringe. Meanwhile, the administrative border of the village and towns which are connected to the built-up area of the city is considered as the exterior border of urban fringe. The border is amended by quantificational index. For extracting the border information of city fringe area, four time phases’ TM data (1984, 1991, 1998 and 2001) of Wuxi was utilized and the semi-automatic extraction models are adopted. The information of land use/cover change condition is drawn through computer-aided interpretation. Then, land use structure and its change of urban fringe in Wuxi were analysed on the basis of the extracted information. As a whole, its characteristic is that cultivated area is reduced fast; the proportion of land for construction increases year by year; the construction of industrial park becomes a common practice; the efficiency of land use is low; fragmentary land use distributed on this area sporadically; the fragmentation of land use/cover type is obvious; the land for construction of the city has expanded orderly; and a homogeneous expansion mode of city-construction-land has formed. In the end, this paper brought forward land use proposisions for urban fringe areas in Wuxi: （1）To strengthen the basic road network construction of fringe area and to promote the coordinated development in urban and rural areas. The intensive river system of fringe area in Wuxi has formed the crooked road network, causing across-river traffic inconvenient. The city lacks a rational and orderly urban road system which can adapt to the modern traffic. With the considerable growth of the motor vehicle traffic, the pressure that road network faces is greater and greater. The construction of the basic road network in urban fringe needs to be strengthened. （2）To strengthen land use planing and controling, especially to strengthen the guarantee for the green ecological space. The kinds of land which have been defined in the land use planning definitely, such as agriculture protection land, water source land, tourism and leisure land, and natural ecology protection land, need to be protected severely through laws and regulations to keep that the cultivated land reduces within limits. （3）To consummate the construction of land market of urban fringe. To accelerate the reform pace of the land use system. To set up a uniform, perfect, open, fair, standard, and orderly land market and land exchange system which meets the needs of urbanization. To change the state of the out-of-order manamegent and uneconomic land use.
With the use of TM imageries of Xuzhou in 1987, 1994 and 2000, the change maps of land use structure of relevant periods of its coal mining areas were compiled, and the classified land use type was divided into 6 kinds, i.e. the construction area, cultivated land, forestland, body of water, subsided land from coal mine and the other land. The situations of dynamic change of land use were analyzed comprehensively, the conversion matrix of land use structure about the different temporal classified TM imageries was interpreted, and the reclamation measures of subsided land were probed. The results indicate that: the area of subsided land due to coal mining was increasing and the speed of land reclamation did not catch up with that of land subsidence. Therefore, it is necessary to accelerate the force to the land reclamation. And from the view of technique, planning, fund and management, it is necessary to adopt the reclamation measures of subsided land, including mainly: (1) to adopt the suitable reclamation techniques; (2) to put forward a general scientific planning on subsided land reclamation of; (3) to construct an effective input mechanism of the reclamation of subsided land; (4) to establish a comprehensive organization to actualize the project of subsided land reclamation.
Jinsha River Basin in Yunnan Province, which is the most ecologically fragile mountain area and one of the areas with the most severe soil erosion as well as one of the areas with most the notable LUCC in China, has been on Chinese Government’s list of the nation’s key areas to be improved ecologically. This paper is to reveal the basic trend of this area’s LUCC and soil erosion change and to provide a basis for the future sustainable use of land resources by studying Binchuan County, a typical place in medium-altitude mountain-plateau and dry-hot valley zone in the middle reaches of Jinsha River. Based on the County’s land use/cover and soil erosion map in 1960, 1980 and 2000 drawn with the aid of aerial photograph interpretation, field investigation and GIS mapping techniques, the paper is to study the County’s LUCC during the period from 1960 to 2000 and soil erosion change arising from it. In addition, the paper sums up the main experiences and lessons of harnessing land ecological environment from 1960 to 2000 in the County, and puts forward some proposals of engineering and techniques for harnessing land ecological environment in the County.
The Yellow River Basin is located in the semi-arid and semi-humid region in China, and there is 200~600 mm annual precipitation and 58 billions annual runoff. The basin is with seriously scarce water resources in China, even less in the world.The region upwards of Lanzhou has area of 222 552 km2, with 446 mm annual precipitation, 319 mm flood season precipitation and 127 mm non-flood season precipitation. But its runoff accounts for 57.5% of the runoff in the Yellow River. So the spatial and temporal changes of water resources in the region upwards of Lanzhou should have great impacts on water resources of whole basin. It is important to research the spatial and temporal structure of precipitation in the region upwards of Lanzhou. It is known that, climatic system has some typical characteristics of multi-scales space-time, multi-hierarchy structure and non-linearity nature, and that the relationships and actions among different hierarchies are intricate. In this paper, with 1959~1998 precipitation series at 19 precipitation stations of the region upwards of Lanzhou in the Yellow River basin, the spatial and temporal structure features and changes of precipitation are analyzed with Empirical Orthogonal Function (EOF) method. The results show that: (1) there are four types precipitation structures in the region, and they are “All- Consistency”, “North-South”, “West-East” and “Complex type”; (2)the first eigenvector is the dominant type, and its accumulation contribution rate is 42.10%. Its time coefficient has same change as precipitation. This shows that the precipitation in the region upwards of Lanzhou is controlled by large-scale climatic system of Qing-Zang Plateau and the precipitation has more or less consistency; (3) from time scale, the precipitation has downwards change with 3, 6, and 11 year periods, with two abrupt points happening in 1986 and 1991.
Taking Chaobaihe Basin as a study area, and using the data from 58 stations in 1990, this paper analyzes the uncertainty in the spatial interpolation of rainfall data caused mainly by the number of stations, temporal scale, cell size of interpolation grid and different interpolation methods. IDW, Kriging, Spline and Trend methods are all adopted in the paper work. The results imply that:(1) the more the number of stations in the interpolation,the less the uncertainty reflected by MAE in rainfall data interpolation; but for certain point, adding some more stations will not absolutely increase its accuracy because of their spatial distribution;(2) the variations of cell size from 50m, 100m, 200m to 1000m does not affect the accuracy remarkably; (3) when temporal scale is shortened from year to month and day, the uncertainty of interpolation results based on the same number of stations increases greatly; (4) different interpolation methods bring different levels of uncertainty. According to the analysis above, the basic way to reduce the uncertainty in rainfall data interpolation is to introduce other relative variations with high sample density, and to integrate them in present interpolation methods. So the choice of those relative variations and their integration with interpolation methods should be the core of the future research in rainfall interpolation.
The transformation of land use change and its driving mechanism have been a hot topic in the existing studies of land science. It has been commonly recognized that human factor is the major driving force underlying the regional land use change. Based on the data collected through documentary research and field observation, this paper shows that since 1990s, land use change in Wenzhou City has displayed such important features as decline of cultivated land area, water area increase, and fluctuation of unutilized land. The main driving forces in Wenzhou City are found to be regulation of governmental policy, urbanization process and economic stimulus. They coexist and intertwine with each other but have distinctive channels of impact. Through this case study, the authors suggest that in regulating regional transformation of land use, attention should be paid more to the specificity in the concrete regional context in which human driving forces are articulated together to effect land use change.
Land is the most important physical basis for the existence and development of the human being. With the growth of population and the rapid development of industrialization and urbanization, the shortage of land resources is becoming more and more serious. It has been felt that land must be used rationally. Now the optimal allocation of land resources is becoming a significant study task, and the land use and land cover change study plan, which is attached importance recently by academe, can offer support and accelerate each other. Therefore, how to understand their relationship and make use of the relationship effectively becomes the key problem. It not only can help the study of land use and land cover change but also is important to the optimal allocation of land resources. In this paper, the main aim and content of LUCC are firstly introduced and analyzed. Based on the analysis, the way of connecting land use and land cover change with regional optimal allocation of land resources is discussed systematically. It presents that land use and land cover change study can offer data, theory and technology support to the study of land resource optimal allocation, and at the same time, the study of land resource optimal allocation can make the study of land use and land cover change deeply and profoundly. The connection of them can promote the sustainable land use.
The terrestrial carbon source or sink was influenced by global climate change and land use change. Afforestation, as a type of land use change, can add terrestrial carbon sink and alleviate atmospheric CO2 increment, which was recognized as a counteract measure to the national GHGs emission by internationals and governments. Study on the influence of afforestation on terrestrial carbon sink has become one of the research hotspots in global change and forestry practice. Terrestrial carbon sink and its source were summarized firstly in the paper and the importance of afforestation on terrestrial carbon sink was affirmed. Then the influencing approach of afforestation on terrestrial carbon sink, the change of vegetation and soil carbon and their relationship after afforestation was discussed, and the potential of global afforestation on terrestrial carbon sink was presented. Finally, the shortage of current research and the emphases of future research were given. China has the largest plentation area, with nearly one third of the global total, strengthening the objective research of afforestation and its terrestrial carbon sink, will have an important politic, scientific significance in China.
It is certain that the global climate has changed a lot. Carbon dioxide is an important greenhouse gas. Carbon dioxide reduction is an important measure to mitigate the greenhouse effect and it becomes a hotspot of climate change researching. This paper introduces systemically and generally the study on reducing carbon emissions from these aspects of IPCC & country groups, economy and professional technology. On the policy layer, this paper introduces the activities of IPCC and country groups differentiated from their opinions on KP. In economic aspect, it describes some quantified models, mechanism of carbon tax and ancillary effects of carbon reduction. Professional technologies takes the key role to reduce carbon dioxide emissions. This paper introduces the study on carbon activity including carbon sink, carbon stock, carbon cycle, the application of industrial technologies of reducing carbon dioxide emis-sions, and so on. Lastly, this paper puts forth some measures in brief on the research of reduction of carbon dioxide emissions in China.
Soil organic carbon releases CO2 at the aeration status, which results in greenhouse effect and consequently influences global change. Currently sequestrating CO2 to agricultural soil is a front field in soil carbon cycle studies, among which whether agricultural soil redistribution leads to carbon sequestration has developed scientific,political and social interests. In this paper, the effects of soil redistribution on soil organic carbon in multi-scales are discussed. The significance of soil erosion and redeposition in the study of terrestrial carbon cycles, the relationship between soil redistribution and the missing sink, and the mechanism of carbon sequestration resulting from soil redistribution are expounded. Based on above analysis the stringent problems needed to resolve are put forward.
The Tibetan Plateau, well-known as the ‘roof of the world’ and the ‘third polar of the earth’, is the youngest and most immense plateau on earth. This paper summarizes and analyzes research results and conclusions with respect to the environmental effects of the Plateau. The plateau shows particular environmental features, such as high cold climate and unique ecological patterns known as “Tibetan zonation”. It also has deep influence on the climate and vegetation patterns of East Monsoon China, Northwest Arid China, the Asia, and even the whole world. The climatic effects of the Plateau include its distinct plateau monsoon system and the formation of modern monsoon system of China. The plateau is characterized by frequent natural disasters, e.g., forest degradation, soil erosion, earthquake, landslide, debris flow, etc. Huamn impacts on the plateau could not be negleated, although they are not very strong.
As human society being rapidly urbanized, the future of most landscapes is increasingly being determined by human activities. These activities modify existing landscape patterns and processes either deliberately or inadvertently. It is becoming increasingly apparent that an understanding of these landscape level patterns and processes is essential for rational land use planning and management as well as for production and biodiversity conservation. This paper aims at introducing the progress in research on ecological impact of urban landscape structure through the best available and current literatures, foreign and domestic. According to those studies, ecosystems are impacted by the urban landscape in two aspects: landscape pattern and landuse/landcover. Based on the overview of recent studies, it can be argued that, to get a high-quality urban life and to improve natural environments, the distributions of landscape pattern are required to be integrated with its functions.
The analytical scheme on scale-structure of geographical space is one of the most important fields in the study of geographical space. Based on scale concepts from geography and landscape ecology, and applying hierachical theory, the paper discusses the issue on macro-, middle- and basic- scales. A spatial hierachical order is primarily setup to present structures and functions of geographical space. The order can be used to reflect spatial structure com-ponents of epigeosphere on different scale levels and their transformation among different levels. The order will help us to find out inherent causes and their forming ways of kinds of geographical phenomena on the basic scale, and to explore representation of different regional geographical phenomena and their dynamic mechanism of changing process on the middle scale. Traditional geography has advantage to research macro-space with disadvantage for micro-scale. The reasonable cognition for the hierachical order will be useful for geographical studies on combination of macro mechanism and micro function. It will also be foundation for integration of qualitative and quantitative methods in modern geography.
