Reduce- recycle- reuse becomes more active in China in natural resource development and uses. With the high pressure on natural resources in China's socio- economic development, 3R industry experiences a new milestone during the last ten years. By the end of 2005, 23 512 enterprises are engaged in the 3R industry in China. In order to find the differences of the 3R industry development among the provinces in China, a statistic methodology with 14 socio- economic indicators linked with the 3R Industry GIS Database of China has been applied in the analysis of 3R industry in China's provinces. Guangdong province is at the top level in 3R industry development in China, which has 4 996 enterprises. Jiangsu(2 267), Zhejiang (2 259) and Shandong(2 217) provinces run the second level 7 provinces, Hebei, Shanghai, Fujian, Liaoning, Hubei, Hunan and Henan, run the third level, with the number of the enterprises in each province ranging from 600 ~2000. The provinces of Tianjin, Beijing, Sichuan, Anhui, Jiangxi, Helongjiang, Guanxi, Shanxi, Chongqing, Jilin and Hong Kong run the fourth level, with the number of the enterprises in each ranging 200~600. And other provinces are lower than 200. The spatial pattern of the 3R industry in China is that it declines from eastern to western in the terms of changes in population, economic development and the local policies. Based on the analysis above, recommendations have been provided in this paper, including: (1) the official statistics agency of China should pay more attention to the statistics in the 3R industry development in China, and as a more practical action, a survey on 3R industry census in China is necessary; (2) The national guidance and management policy for 3R development and spatial distribution should be made available; and (3) the standards for 3R industry development and the 3R industry monitoring systems in the national level should be established as soon as possible.
In the background of global climate change, the effect of drought on ecosystem structure and function has been paid more and more attention to. In this paper, for the purpose of presenting approaches to elucidate the mechanism of drought effects on ecosystem processes, we reviewed the effects of drought on carbon/water processes at individual level and community level. At the individual level, drought can make plant change its physiological and morphological traits to conserve water, such as decreasing stomata conductance, increasing solute content, changing stomata density and size, increasing specific leaf area and belowground biomass allocation, etc. In addition, different plants have different water - use strategies. Their physiological and morphological traits responding to drought are apparently distinct. At the community level, similarly, drought can change vegetations physiology and structure, such as photosynthesis, respiration, transpiration, water use efficiency, biodiversity, productivity et al. Despite that most aspects of drought effects on ecosystem are included in current studies, they are isolated from each other. To fully understand how ecosystem responds to drought, it is essential to combine all methods available, to synthetically study the processes coupling with each other (e.g. carbon cycle, water cycle and nitrogen cycle), and to construct a theoretical system to connect different time scales ( from minute to decade) and levels (from leaf to ecosystem).
In recent years, estimating vegetation growing season on large scale has become a sig-nificant scientific field in global climate change studies. NOAA/AVHRR NDVI provides important means of research on temporal and spatial variability of vegetation growing season. This paper has summarized, compared and analyzed methods of estimating beginning, end, length of vegetation growing season on the basis of NDVI: NDVI threshold, NDVI time series analysis, combination of frequency distribution pattern of plant phenology with NDVI, principal component analysis, curves fitting model and so on. Influenced by different factors, each method has different limitations in application. Therefore, it is necessary to seek better methods for determining interannual and regional distribution variability of vegetation growing season. And on the basis of previous studies, growing season of grassland in Xilinhaote from 1991 to 1999 is estimated by NDVI threshold method, smoothed moving average, the greatest change slope, and curves fitting model. Then the results were verified with grassland greenup by field survey. Results shows that, combining with field surveying data, grassland greeup with better accuracy is acquired with NDVI threshold method, and curves fitting model can be applied to monitoring vegetation growing season on large scale. However, it is difficult for actual curves to match the simulated curves. Therefore, it is very important to choose appropriate fitting curves for subsequent studies. Furthermore, it is necessary to carry out further research on interannual variability of vegetation growing season.
Both abundance of energy and cleanness of environment are of paramount importance to guaranteeing the national energy security and sustainable development. Considering coal's important place in the energy supply and consumption structure, the big population in rural area and the sustainable development plan in the future, there are special practical significances to carry out energy- environment researches in China. This article summarized the concept, the analysis frame and theory base, and the usual methods and models in the energy- environment field. An energy- environment cube analysis frame was also given to conclude the main research aspects such as different kinds of energy utilization on environment, effects of fossil energies on global environment, and influences of rural energy and biomass energy on eco- environment which is less studied at present and especially from the viewpoints of geographical scale. After some reviews and comments on the research advances in economic, technical, political and regional demonstration fields of both domestic and international communities, the future trends and some perspectives on the energy environments are put forward at the end of the article.
The transect data of morphology and grain- size samples has been obtained from a transverse dune with 8m high and 48m long in the south edge of Mu Us Sandy Land in the period of wind direction transitions. The results show that there exist temporal changes in grainsize and its spatial pattern on transverse dune responding to different wind directions and magnitudes. These changes are more obvious in the creastal zone of dune with more sand activity. Great temporal changes take place in the grain size frequency distribution, mean grain size and skewness among the grain- size parameters. This suggests that these parameters are most susceptive to the wind, and so their changes can be used to explain the difference of dunes in the influence of different wind. The evidences of the wind direction, dune morphology and grain- size characteristics identified there not only have seasonal but daily changes in grain- size patterns on the dune when wind direction changes. It further confirms the conclusion that the time of sampling is as important as the site.
Road construction would accelerate soil erosion, which in turn would deteriorate natural ecology. To reduce or control road erosion, we should grasp road erosion characteristics and its mechanics, and then find the effective control measures. Landform would be changed to some extent in road construction processes. Different micro- topography would be formed on the original geomorphology, which produces different erosion characteristics. Meanwhile, the erosion mechanics and processes are different among these parts of a road. The existing researches on road erosion have no agreement on the erosion intensity for the respective part of the road. Compared with other land use types, road would significantly change the physical and hydrological properties of soil surface, and furthermore accelerate runoff and soil erosion. Especially for a watershed, the linear feature of a road helps to easily converge and conduct runoff. However, few research on this aspect until present. At present, the statistical model of road erosion prediction is still predominating. Due to the limitation of the statistical model itself, it can 't reflect the erosion mechanics; so physical models should be the emphasis in the further researches. Especially, we should try our best to introduce the existing physical model on farmland. The control measures on road erosion mainly include the engineering ones, the biology ones and their combinations. All of them have different effectiveness in controlling soil loss, dependent on the local natural and economic factors. This paper reviewed the previous researches and pointed out some emphasis on road erosion in further study. It is significant for road erosion control and watershed environment protection.
The technological principle, characteristics and composition of floating phytore mediation systems for water quality restoration were described and analyzed. The growth and effect of Canna generalis and Cyperus alternifolius on TN and TP removal from urban water bodies were also investigated based on experiments. And a new bio - plant technology for water quality restoration of urban water bodies, which combined floating cultivation system with biological contact oxidation, was utilized to purify polluted water of an urban river and a lake in Xi'an City of China. The experimental results showed that Canna generalis and Cyperus alternifolius had better effects on water body purification, and more than 90% of nitrogen was removed by the both systems. And the bio- plant system composed of floating cultivation and soft bio- media could not only remove TN and TP effectively, but also greatly degrade organic pollutants from the water bodies, with a high removal rate of 46% of CODMn obtained.
The seasonal phenology of the leaf area index (LAI) is a major determinant of net e-cosystem production in deciduous forest ecosystems. In the simplest case, the effect of leaf phenology on energy and CO2 fluxes is represented by prescribing leaf onset and offset times or the seasonal evolution of LAI. Leaf phenology remains one of the most difficult processes to be parameterized in terrestrial ecosystem models because the understanding of the physical processes that initiate leaf onset and senescence is incomplete. At present, to describe phenology, the terrestrial models generally use one of two different approaches. One approach uses empirical formulations to estimate the timing of crucial phonological events like leaf- on/off dates only based on abiotic variables, especially temperature or growing degree- days (GDDs). The other approach is a carbon - gain - based scheme. In this approach, the phonological stages are directly determined from the current carbon balance. A carbon- gain- based parameterization of phenology in ecosystem models offers the possibility of reduced empiricism, general applicability, and increased robustness; and it is more suitable for being used in climate change models. In the future, while the mechanisms of processes controlling leaf phenology are clarified with progress being made at the physiological and molecular level, ecosystem models have to set up processbased model of leaf phenology and LAI to promote the robust of simulation results.
Land- use change represents an implication of short- scheduling, better spatial orien-tation and anthropogenic compelling disturbance at the local level. Its processes and results are the most efficient approach for regional - level responses and national - and global - level feedbacks. Urbanization, agrarian structure transformation and land arrangement are presently the driving forces resulting in land- use change at the local level in China. Urbanization is an irreversible process. This process will result in the transformation from county's landscape to city's landscapes, accelerate the change of the characters of underlying surfaces such as surface albedoes and surface roughness, and in crease varieties of the habitat types and species diversities. Consequently, a new patterns of human homogenized landscape will be formed at the local level. Farmer's microcosmic choices of land- use styles are a kind of motility, which results in agrarian structure transformation. The differences in farmer's investment, production and management will lead to the changes of soil quality and environment. Land arrangement is a complex systematic engineering. Its implementation will change the local landscape structure, soil quality and hydrological process. Moreover, these results will influence correspondingly local ecologic environment. Thus, in order to profoundly understand local land use change, conceiving the theoretic frames of“human- land harmonious system”, simulating land use change and evaluating ecologic benefit of land- use change will be the orientation of future research in land- use change at the local level.
Topographic wetness index, which is designed for modeling the status ( “dry”or “wet”) of the soil moisture quantitatively, is an important index for both predictive soil mapping and distributed hydrological modeling in a catchment. Current methods for calculating topographic wetness index have evident problems when applied in low relief area. Outside the positions of narrow accumulation line with high topographic wetness index, the topographic wetness index dramatically jumps down in other parts of wide valley area. This is unreasonable because the soil moisture should be comparatively average and high in the wide and flat valley, and the value of topographic wetness index should be high. This problem is caused by both the flow accumulation algorithm and the slope gradient used during computing the topographic wetness index. A new method for computing topographic wetness index is proposed in this paper to address this problem. Firstly, flow accumulation is calculated by a multiple flow direction algorithm (MFD- fg). Topographic wetness index is then computed by the flow accumulation and maximum downslope. The maximum downslope used in the computation of topographic wetness index is matched with the idea of both MFD- fg and topographic wetness index. Furthermore, a post - processing method is also proposed to compute the topographic wetness index in valley area. The topographic wetness index in the valley area is interpolated by a Gaussian function based on the value of the topographic wetness index on the nearest position on extracted flow accumulation line. The application in a small watershed shows that the method proposed in this paper can get a comparatively reasonable distribution of topographic wetness index for not only the hillslope but also the wide valley area. The value of topographic wetness index in valley area is averagely high and with a smooth transition, which reflects the natural status of the soil moisture in application area. In the future research, the method proposed in this paper will be evaluated by both artificial surfaces and the real applications.
With the integrated technology of Remote Sensing (RS) and Geographic Information System(GIS), the status of LUCC in the mountain areas of southern Ningxia Hui Autonomous Region is thoroughly studied by statistics and conversion matrix based on the remote sensing imagery date of 1975, 1985 and 2001. The main results are as follows. (1) The main styles of LUCC in the study area is farmland, and the following is grassland and woodland. The area of farmland reaches its maximum in 1987, with 790 312.06 hm2, taking 70.03% in the total land area. (2) The study results from conversion matrix indicate that there is 370 770.52 hm2 grassland and 39 813.57 hm2 woodland that had changed to farmland from 1975 to 1987. But from 1987 to 2001, there are 316 865.89 hm2 farmland that had changed to grassland and 50 729.16 hm2 farmland changed to woodland. The main reason that leads to this variation is that the local economy development was based on construction of farmland from 1975 to 1987. In this period, the development policy encouraged farmer to cultivate wasteland. But after 1990, the national exploitation policy changed greatly and carried out some zoology project, especially Returning Farmland to Forests and Grassland Project. Such policies and projects play an important role in the recovery process of grassland and woodland.
Yulin district is located in the most Northern part of Shaanxi province, between 36°57′and 39°34′N, and 107°28′and 111°15′E. Yulin district is one of the areas of the most serious soil erosion in the world and receives a lot of attention from the Chinese government and international societies. After the establishment of the People's Republic of China, the desertification intensity declined because of rehabilitation measures. However, there is lack of knowledge concerning the dynamics of land cover and the complex role of factors in inducing changes in land cover. In the study, by usage of normalized difference vegetation index(NDVI) as an indicator of vegetation activity, seasonal trends of vegetation activity and their dynamic responses to climate changes in Yulin district were explored based on remotely sensed data (NOAA- AVHRR and VEGETATION) from 1981 to 2004. As a result, spatially averaged seasonal NDVI in Yulin showed a pronounced increase during the last two decades. The average autumn NDVI indicated the most significant increase. By analyzing inter- annual changes in seasonal NDVI, it was found that the advance of growing season was a major way for response of vegetation activity to climate changes and that the way exhibited a large regional heterogeneity. From the southeast to the northwest, change amplitude showed a declining trend.
Study on farmland non- agriculturalization and its control mechanisms is becoming an important issue in the framework of LCS ( Land Change Science), a new developing conception by IGBP. LCS stresses not only research on LUCC itself but also other relevant social- economic problems and pays much attention to high- speed change areas all over the world. China, a fast developing country, is facing many land use problems brought by fast economic growth, urbanization and industrialization with fast farmland losing as a core. Taking the capital of China, Beijing, as a case, the temporal- spatial processes of farmland conversion and its control mechanisms are discussed. It is found that ( 1) Farmland losing is the main character of land use in Beijing from 1996 to 2004; ( 2)Among various factors threatening the sustainability of farmland, the most outstanding and the most serious one is the occupation on farmland for urban development;( 3) The lost farmland is mostly those high quality land in the plain area; and ( 4) Farmland losing is driven by population increase, economic growth, some local governments'acts for short- term benefits from farmland conversion and so on. In order to moderate the conflicts between farmland conservation and urban development in Beijing and other fast developing districts in China, the authors claim that the following points should be emphasized in land management:( 1) Importance should be especially placed on the quality of farmland; ( 2) Policies on farmland conservation, such as "keeping quantity balance", should be reviewed; and ( 3) It is necessary to make appropriate control mechanisms for farmland conservation, including: to provide a reasonable threshold of farmland conservation, to establish appropriate legislation, institutions and mechanisms, and to avoid illegal occupation on farmland for urban development, etc.
Three Gorges Project is the great project in the world, which accelerates economic development in the reservoir area of Three Gorges Project. In the process of development in the reservoir area of Three Gorges Project, cultivated land has become an important resource, and a lot of cultivated land has been occupied and become constructing land. At the same time, a lot of cultivated land has been flooded because of the rising of the water level. This paper uses the cultivated land areas and social economic indicators of reservoir area of Three Gorges for 1990~2004, takes the statistic analyses and example research in order to analyze the process of cultivated land, gets the driving forces of cultivated land change, finds the new methods to stimulate and forecast the cultivated land areas in the future, and serves for the cultivated land protection and sustainable development in reservoir area of Three Gorges. The results indicate that, firstly, in the past 15 years, the cultivated land area has decreased by 200 142 hm2, and the decreasing quantity per year is 13343 hm2
With the development of express ways, they has became the main transport model of road system, affecting the development of social- economy and urban region. In this paper, based on the research history and progress in China, the author analyzed the spatial evolution course of express way networks in China, which have the slowness development ( 1988~1997) and quick development stage( 1997) , and discussed their spatial organization models, including regional access, urban circle road, access between hub cities, urban interior road, and travel road. Furthermore, by designing the shortest time model and O- D matrix, the author analyzed the regional impaction of express way networks in detail. Firstly the evolution of traffic flow structure in China was discussed, which enlarged the transport distance of road system and actuated the traffic to concentrate in the East region of China. Secondly, the author analyzed traffic flow structure of urban regions and its region system, which emerged as the main traffic flow access and hub - and - spoken system in Yangze delta and Pear river delta urban regions and Thirdly, the express transport circle of 30M and 1H around province cities were discussed and drew the conclusion that express way enhanced their service scope and accelerated concentrating speed of population and products to province cites.
Urban spatial morphology is an important aspect in the huge and complex urban system. The essential rule of urban development and change cannot be understood via qualitative description, so quantitatively researching urban spatial characteristic has significant practice meaning for urban management and planning. Based on remote sensing, GIS and Landsat TM/ ETM digital images, this paper analyzes the spatial- temporal changes of urban spatial morphology at the northern slope of the Tianshan Mountains in Xinjiang during the period from the late 1980s to the late 1990s by computing compact rations and fractal dimensions of the urban form as well as the types of urban land expansion. The results are as follows: (1) The spatial- temporal changes of urban spatial morphology at the northern slope of the Tianshan Mountains belong mostly to compact and regular ones. (2) The average compact rations are 0.541 and 0.525, and the mean fractal dimensions are 1.2399 and 1.25 respectively for 1990 and 2000. The type of urban land expansion of 7 cities out of the 8 in the study area is 'extension'from 1990 to 2000. It was found that the shapes of cities in the study area tended to be less compact and more fragmentized. Generally, a more compact city has more advantages than a less one; so changes in the forms of the study area are considered being in a bad way. Shapes of several cities have been drastically changed during the period from 1990 to 2000. Fukang, Miquan and Shihezi are cities with high increment in fractal dimensions and high decrease in compact rations. Urban spatial morphology of them is more compact and regular. However, it is another case in Kelamayi, Kuytun and Urumqi. And (3) Another important finding is that there is a power function relationship between the compact and the fractal dimension of urban spatial morphology, which is only a qualitative deduction before.
