The Qinghai-Tibet Plateau is a unique geographical region with the highest elevation located at unique latitudes in the world and shows special dynamic and thermal effects, thus responsible for a conspicuous hydrological cycle in the atmosphere within Asian monsoon areas, and an extremely sensitive region of land-air interactions in East Asia. It is also one of areas which is less disturbed by human activities on the surface of the earth, serving as a foreboding or early-warning area for global changes. Wetland, located in the transitional zones between aquatic and terrestrial ecosystems, is an important landscape and ecosystem. Wetlands in Qinghai-Tibet Plateau mainly include alpine marshes, alpine swampy meadow and alpine lakes, which play important roles in water storage, water supply, adjusting climate and abating global water shortage and so on. Therefore Wetlands in Qinghai-Tibet Plateau are very important for global climate changes. In this paper we summarized progresses in several study fields of wetlands in Qinghai-Tibet Plateau, such as classification of wetland types, wetland soils, wetland vegetation, formation and evolvement of peat, wetland creature, paleobotany and pristine climate, greenhouse gases emission and wetland degeneration etc., indicating that wetlands in Qinghai-Tibet Plateau have been paid much attention to. But studies on these fields also need to be strengthened. Finally, the study fields in the future were also put forward as follows: (1) Relationship between landscape pattern of plateau wetlands and ecological processes such as sediment processes, biogeochemical processes, eco-hydraulic processes; (2) Relationship between global climate changes and dynamic changes in wetland landscape patterns, including greenhouse effects and global carbon cycles, and relationship between pristine climate and pristine environment changes; (3) Restoration and conservation of plateau wetlands serious degenerated, including degeneration processes and forcing mechanism, ecological methods for restoration and conservation and index system of ecosystem health assessment and ecological risk assessment.
Applications of remote sensing in the study of terrestrial productivity open up an effective way for simulating terrestrial ecosystem productivity. In this paper, according to transferring process of solar radiation between atmosphere and land surface, and canopy photosynthesis, MODIS-based models are established to parameterize carbon assimilation by terrestrial plant communication, focused on photosynthetically active radiation absorbed by all surface materials (APARSFC), ratio of PAR absorbed by plant canopy to APARSFC (RPAR), and radiation use efficiency (RUE): (1) A new approach for daily net PAR flux is established, integrated of incident PAR at the top of atmosphere, the total transmission for atmosphere, land albedo, land-surface incident sun-light, and solar hourly angle change during a day, instead of field observation and converting coefficient. And then, daily APARSFC is accumulated to composite monthly APARSFC. (2) RPAR is estimated by an empirical model with FPAR. (3) RUE is evaluated by a biophysically based approach with respect to Amax and leaf area index. The variation of Amax within the canopy is assumed to be governed by its dependence on specific leaf nitrogen, which varies with the canopy due to aging of leaves and acclimation to prevailing irradiance. The parameterized models are further applied to simulate NPP of temperate deciduous forest in Northeast China in June 2003, consisting of deciduous broadleaved forest and deciduous coniferous forest. The results show that APARSFC of temperate deciduous forest woodland in Northeast China gets to climax, the mean PAR values of deciduous broadleaved forest and deciduous coniferous forest reach 8.24 MJ m-2day-1 and 8.63 MJ m-2day-1; with growing leaves, RPAR of most forest canopies is more than 0.5, and saturates in partial forest woodland; RUE varies between 0.45 and 1.09gC MJ-1, the mean RUE is 0.71gC MJ-1 for broadleaved forest, 0.69gC MJ-1 for coniferous forest; monthly NPP is 0.53MgC ha-1, and 0.56MgC ha-1 for deciduous coniferous forest, while 0.51MgC ha-1 for deciduous broadleaved forest. Compared with process-based model, both of them are in agreement with predicted NPP.
Along with the rapid development of economic in recent years, the level of people life and society production have been greatly improved in Altay Prefecture, Xinjiang. Its ecology environment problems, however, have been becoming more and more serious and have become the major restrictive factors for the rapid and sustainable economic development in Altay. They are as follows at present:(1)grassland degeneration;(2)forest decrease;(3)soil secondary salinization; (4)land desertification; and so on. In this paper, the main ecology environment problems existing in Altay Prefecture are discussed, and their formation causes are analyzed. It is pointed out that sustainable development is the urgent demand and necessary choice for the economic and society development in Altay Prefecture. Based on these, Some countermeasures are put forward. For examples, it is suggested to restrict population quantity and enhance people constitution, to strengthen the enforcement of environmental protection laws and build up environmental awarenees, and so on.
One of the key goal in the United Nations Framework Convention on Climate Change (UNFCCC) and the Kyoto Protocol is that reducing greenhouse gas emissions and control climate change. The main developed countries, such as US, U.K., France, German and Japan, have cost several hundred years in their industrialization. As a result, they have accumulated some advanced technology and experience in energy saving and CO2 emission reduction. As China′s economy developed fast and population increasing, energy will be exploited greatly and the emission of CO2 will also be increased greatly. So we should make our best endeavors to control and reduce the emission of greenhouse, whether in the view of sustainable develop or under an international obligation. In order to reduce the emission of CO2 and realize sustainable development we should learn the developed countries experience on energy use, structural adjustment and energy saving. Some foreign experience we can learn from is as follows: (1) planning and carrying out development strategies of rational energy use and CO2 emission reduction; (2) establishing and improving laws; (3) adjusting energy structure; and (4) implementing economic incentive policies and measures.
The flux of carbon from grassland to the atmosphere occurs primarily in the form of CO2，and is the result of soil respiration，which makes that the soil respiration is one of the major pathways to influence the global carbon cycle. Increasing release of carbon from the soils could significantly exacerbate the increase of atmospheric CO2 and reinforce the greenhouse-warming effect. In this paper，the commonly used methods of measuring soil respiration were summarized and compared in particular. Factors affecting soil respiration, such as natural conditionts and human activities, were discussed. Finally，four primary methods have been reviewed to distinguish root respiration from total soil respiration including components method，root exclusion method，root biomass ratiocination method and isotope method. The paper suggested that the more studies are necessary in the future work.
The carbon cycles in the soil is important for the study of the global change because the carbon deposited in the soil is two times more than that in the atmosphere and three times more than that in the plant and animal. While the final mechanism of the terrestrial carbon cycles is still not clear without the understanding of the soil dynamics, the radiocarbon provides a simple and convenient method to study the turnover of the soil organic matter (SOM). Several models and methods in the study of soil organic matter turnover by the application of radiocarbon were introduced in this paper. It was pointed out that the SOM radiocarbon application may be used to study the carbon cycle of longer time scale such as decades and more, whereas its application to the soil CO2 can be used to study the carbon cycle of shorter time scale such as seasons or one year. Other applications such as those in the study of fine root age and land use change were also introduced in this paper. Although radiocarbon had been used in the study of carbon cycle, its application was very limited so far and some problems had been found. At last, some issues unsettled were put forward and the future development direction and fields using this method to study the SOM dynamics were introduced.
Changchuan Watershed in Inner Mongolia is located in a soft sand-rock area at the middle reach of Yellow River. Based on the image data from Landsat-MSS in 1976, the image data from Landsat-TM in 1998 and in 2000, the land use/cover patterns and their changes in the watershed have been analyzed in this paper by means of RS and GIS techniques. The preliminary results are as follows: 1) Changchuan Watershed is dominated by three land use types, i.e. shrub-land, grassland and the unusable land, covering over 75% of the watershed in total. 2) During the period from 1976 to 2000, through integrated measures of soil and water conservation, woodland and shrub-land areas greatly increased, but some woodland and shrub land have been transformed into unusable land, sandy land or farmland. In the meanwhile, the area of water body distinctly decreased. 3) The biological measures of soil and water conservation such as forestation and grass planting, the cultivation expanding and the variation of annual precipitation might be the main factors leading to the land use changes in the area.
Simulation of land use change spatially is the important base for analyzing land use scenario. On the base of introducing Cell Autumat model (CA) and Conversion of land use change and its effects (CLUE) model, Conversion of land use change and its effects——small region model is analyzed. CA model fits to simulate urban land use change , Shenzhen city’s land use change is simulated with this model. CLUE（Conversion of land use and its effects） model fits to simulate land use change in macro scale, It has four main modules including demand module, population module, production module and spatial distribution module. Land use change of China from 1991 to 2010 is simulated with this model. And CLUE-S model fits to simulate land use change in micro scale and have wide applied field. To take Handan district of Hebei province as an example, the SPOT image of this district in 1995 is processed, and its relative driving force including altitude, gradient, soil classification, the distance to main road, to general road, to central city, to main cities and nearest resident area is also analyzed. Three scenarios are selected: the first is policy-driving land use scenario in 2010, the second is economic-driving land use scenario in 2010, and the third is sustainable development driving land use scenario in 2010. and a series parameters are set. Finally, the following result is put out: to set up the statistic relation between driving force of land use change and spatial distribution by experiential model and simulate land use change scenario in short time is the core of CLUE-S model. In this model, The competition of different land use types is better resolved in CLUE-S model, it is a effective model for simulating land use change; considering the driving force of land use change in short time mainly related to soci-economic factor, and it is still difficult to distribute soci-economic factors in space, to resolve this problem is the key to develop and apply CLUE-S model; Since it can deal with the spatial distribution in different scale, CLUE-S model has expansive applied value in land production potential assessment and land use planning fields.
Urban regeneration is a natural outcome of urbanization. Since the beginning of 1950s in last century， urban development conception in western countries has changed 5 times so far from urban reconstruction in 1950s to urban revitalization in 1960s， urban renewal in 1970s， urban redevelopment in 1980s， urban regeneration in 1990s. Each concept represented very rich contents of that time， and was well substituted the before by the behind. A mass scale urban reconstruction in China was initiated just after the People’s Republic of China was found in 1949， but the great achievement has been reached in the last 20 years when “the reform and opening policy” was in operation successfully， which includes both the practical experiences and the theory introduced and utilized in practice such as “ urban organic regeneration theory”. It is reasonable to believe that all the large cities in the whole country will unavoidably march on the road of regeneration in 21st century， so far as the urban regeneration is an intension and quality oriented policy to take. In the regeneration process， China is going to dell with 5 respects issues such as deindustrialization and tertiarisation in the big cities industrialized cities， suburbanization and gentrification particularly in regional central cities， community construction and employment as one aspect of countermeasures for providing more jobs， urban historic and cultural heritage protection and utilization as one important sector for developing tertiary， urban regeneration legislation and planning and management which is needed to be enhanced part in urban regeneration activity.
This paper designs index system including structure， function and harmonious degree for assessing level of ecological city in inshore regions in China， and brings forward a methodology of assessment. 16 cities assessed and compared are Dalian， Qinghuangdao，Yingkou， Jinzhou， Qingdao， Rizhao， Lianyungang，Shanghai，Ningbo，Hangzhou， Shaoxing， Zhuhai， Shenzhen， Dongguan， Zhongshan， and Guangzhou. Quantificational analysis of degree of ecological cities is through mathematics model involving population as well as ecological, environmental, economical and social indexes. In the assessment system， there are three first -level indexes， ten second-level indexes and twenty five-third level indexes. The results show that the sequence of ecological level is Shenzhen > Zhuhai > Ningbo> Dongguan> Guangzhou> Shanghai> Dalian> Hangzhou> Qinghuangdao> Zhongshan> Shaoxing> Qingdao> Liangyunguang> Jinzhou> Rizhao> Yingkou. In the 16 cities， the city of highest level is Shenzhen whose value is 1.19， and the city of lowest level is Yingkou whose value is 0.34. The restraining factors that affect the level of ecological city are analyzed too， and results show that atmosphere condition and noise are main factors impacting the advancing of level of ecological city widely ， so the result of research can become the basis of the constructing of the ecological city.
In urbanization progress, population changes are the main factor to understand all other changes, especially land use changes. Through the study on population urbanization and its influence on land use, we can master the whole characters of urbanization development in certain region. And this will be important to urbanization research and the discussion of connection between population and land. Based on methods of GIS and statistics, we analyze the urbanization progress, the population changes in time span, in space and in employment structure and the influence of population changes on land use changes in Suizhou city. The study shows: (1) In Suizhou city, the urban level is at the second stage (>30%) and the urbanization develops in the same rate as the industrialization. (2) In urbanization progress, the urban population increases rapidly but total population has begun to decrease. And the population distributes evenly in the whole region while also concentrating in the center city to some extent. (3) Relative to the second stage of industrialization in Suizhou city, the proportion of agricultural employment is higher than normal. And this results from its natural conditions. (4) In Suizhou city, population changes influence on land use mainly through the expansion of cities using agricultural land, especially cultivated land.
Voronoi diagram is a very useful tool for spatial analysis of many geographical problems. However, we now still lack a simple approach or a software to construct Voronoi diagram with general generators (such as curves and areas), and so this paper presents a GIS-based Approximation Algorithms for Constructing Voronoi Diagrams with general generators. We first replace each generators with a finite number of points that approximate the original generators, then the Voronoi diagrams for these points are constructed, and superfluous Voronoi edges and superfluous Voronoi vertices are finally removed. Thus we can get the approximation of Voronoi diagram with original generators. In practical implementation, we fully employed the module of ARCGIS software with a fast and robust algorithm to construct the ordinary Voronoi diagrams, and also some other modules of it. The result of experiment shows that it is an efficient and effective method for constructing Voronoi diagram with generators of any form figures, and it is a promising approach for the need of geographical research issues. For example, Voronoi diagrams by this approach can be represented as he spatial effect area for a variety of geographical objects with the different forms, such as points (cities, towns, transport junctions, trade centers), and lines (transport lines, industrial belts, river system), and areas (economic regions, parks and green lands), and so forth.
As economy booms in China, the number of town grows rapidly. The rapid urbanization has brought many problems, such as the abuse of land development, the chaos of construction market, etc. Informationization based on GIS, RS and GPS is dedicated to this aid, that is, to build up Geographical Information System of planning and construction of town. However, the biggest obstacle of informationization is the cost of building the spatial database, which most of towns cannot afford. For this problem, by linking high-resolution remote sensing data, SuperMap GIS, and GPS, this paper proposes a workable solution. Quick Bird Image of towns, digitized surveyed maps and planned maps, and CAD data are available for this purpose. Firstly, CAD data is extracted and reclassified into layers according to Land Use Planning Database Standard for County; if CAD data is not available, maps can be changed into vector and then classified into different layers. Next, Quick Bird Image is used to complement and amend the layers, that is, to com-plement somewhere if it is still blank and to update somewhere if it already changed. Finally we render the layers with new color, symbols, linestyles or hatches. This solution is practical since data noted above can be acquired not only easily but in low cost; for example, up-to-date Quick Bird Image can be bought at the price of RMB 200~300 yuan/km2 , Supermap GIS software is easy to use. We test our method for the Houshayu Town in Beijing. The results confirm the effectiveness of RS-based approach. It spares not only money but time since two workers can build such a database successfully in three weeks.
