The Mountain-Basin System(MBS) in the northwestern arid zone of China consists of mountain vegetation vertical belt system and concentric circular vegetation (geologic and geomorphic) system of desert basin. The MBS contains three “circles”: mountain, pedimont fan and alluvial plain, including nine belts, they are alpine belt, montane forest-grassland belt, low-montane desert belt, gravel gobi desert belt, agricultural oasis, marginal belt of diluvial fan, alluvial desert plain, sandy desert belt, and lake. The above-mentioned zonation is the most essential existence and functional pattern of those precious natural resources. It is the presentation of an irresistible rule of the nature and, also, the guidance system of ecological conservation and land use. Basing on this foundation, a “mountain-oasis-ecotone-desert eco-productive paradigm”is proposed. The MBS is it’s basic frame. It’s driving forces are biogeochemical circulation, biogeophysic process, and biogeosocial interaction, which run through the whole system. Thus, the establishment of a sustainable agricultural system and an optimized land use and land cover structure and pattern, which aimed at ecological conservation may be possible.

The research is based on data derived from fieldwork that is interpreted using fractal theory. The present study relied on multi-time satellite remote sensing data for the main sources of information. With the aide of image analysis techniques, desertification of Qira county and changes in the oasis-desert ecotone are analyzed.. In addition, the function of fractal theory in highly quantitative research of oasis-desert ecotones is discussed.. We suggest that the model derived from the present study should serve as a reference in decision-making concerning regional development and construction in order to simplify existing research processes.

Current estimates of land cover and land use are important aspects in understanding the flux of material and energy from terrestrial ecosystems into hydrological and atmospheric components of the earth system. These land use characteristics define the various dimensions of human impacts on ecosystem processes and resource use. The recent availability of global remote sensing data and agricultural census data from various regions of the world, including portions of Asia such as China and Mongolia, now makes it feasible to evaluate differences in the physical environment and land use patterns affecting land cover and land use changes. In addition, recent research involving transects studies along gradients of climate, soil, and land use intensity has been carried out during the past decade to allow more careful regional comparisons. Using the analysis of the Mongolian-North East China Transect (NECT), we can estimate the effect of land cover differences on ecosystem dynamics. The 30 m-Thematic Mapper data provides a way to identify fine scale features of the regional landscape patterns which are not captured by the 1-km AVHRR data. The focus of this paper is to evaluate the scale of land use and cover changes in the Asian region and the biogeochemical implications of these changes. The estimates of land cover and land use can vary depending on the spatial scale of the features represented across the land surface. Both physical and social factors influence the spatial extent these features represent. Therefore, the scale of land use intensification can affect the accuracy of land use area estimations. In particular, those regions of the world where land use practices are implemented via small individual holdings may be underestimated when using coarse scale remote sensing data such as AVHRR, where as the Thematic Mapper satellite data at 30 to 50 m resolution can provide a better estimate of land cover and land use area. The accuracy of the extrapolated fluxes of ecosystem dynamics and biogeochemical cycles are directly proportional to the accuracy associated with the land estimates. We will evaluate the land cover estimates in this region of Asia using these data sources. This region encompasses a broad set of precipitation and temperature regimes and includes characteristics of regional land cover and land use related to grazing systems and grain cultivation.

An oasis is a type of landscape that is only present in arid regions due to the arid climate, landform, and hydrological pattern. It is important to study the stability of oasis to keep sustainable development of regional economy. The stability of oasis is affected by many factors. Human activity is one of major factors. Those non-human factors like salinization in the oasis and desertification in surrounding areas are also critical. Both salinization and desertification are related to water, energy transformations and interactions among different ecosystems. The stability of oasis is influenced by the distribution and utilization of water resources, interactions between ecosystems and climate. Adjustment in the groundwater table may help to prevent the secondary land salinization. It is important to limit salinization and desertification for the stability of oasis.

Given the strategic development of industry and economy over northwest China, the ecosystem over the region will dramatically change. In particular, an increasing proportion of the land is expected to be covered by vegetation, including grass, trees and crops. At the present, most of the region is in desert or semi-desert conditions, where vegetation is very sparse and precipitation is low. A serious issue is the sustainability of vegetation: will the future regional climate conditions favor the maintenance of the vegetation under managed or unmanaged environments? As an initial step, a high-resolution regional climate model (RCM) is used to study the climate responses to an extreme case, where the dominant land cover over Xinjiang, currently barren or sparsely vegetated, is all replaced with grasslands. The simulations show that, in response to the grassland replacement, Xinjiang summer mean precipitation will increase, surface air temperature will decrease, and surface soil wetness will rise. In addition, the diurnal range of precipitation (temperature) will be enhanced (reduced). These changes result mainly from the increased surface evaporation which in turn is attributed to the enhanced surface water availability (greater green vegetation cover and wetter soils) for regional recycling, while the surface albedo and roughness effects are relatively small. The resulting climate responses tend to favor the grasslands to naturally grow in and be adapted to the new regional environment over Xinjiang. On the other hand, precipitation will decline over the Inner Mongolia, which is particularly damaging since the regional grassland there is currently China’s main pastureland and is experiencing dramatic desertification. The uncertainty in the credibility of the RCM results, however, warrants further comprehensive studies, where an interactive ecosystem and global climate changes must be incorporated.

This study is located in Tarim Basin southern part of Xinjiang Uygur Autonomous Region, China. Owing to the special landform of the basin, it has considered as one of the most representative region in arid and semi-arid lands in the globe. More and more scientists had paid attention to focus on its land-use and land-cover change. Expanding oases, soils salinization and dying poplar forest are the major changes in this region over the past forty years. Thus to investigate the reasonable causes and consequences for above three highlights, post-classification comparison change detection, which was considered as one of the most effective method among change detection techniques, was carried out between two satellite images of Landsat ETM in 2000 and Corona panchromatic in 1964. This paper is also concerned with the exact selection of experimental sites in critical region by individually designing several comparable areas for corresponding research purpose aimed at extract human-induced impacts from natural formed influence. In order to have a general understanding of this region, relative researches such as climate change as well as socioeconomic evolution was also discussed.

This paper investigates the oasis expansion and land use changes in arid Manas River Valley using imageries of Landsat MSS, TM and ETM, land use and topographic maps. Over last 50 years, oasis area increased from 156.385km² in 1949 to 5042.440 km² in 2001. Oasis expansion process over last 50 years can be divided into oasization and urbanization stages according to the rate of increase. Farmland quickly increased from 156.4 km² in 1949 to 3639.5 km² in 1976 during the oasization stage with an annual increase rate of 129.004 km²/a. In urbanization stage from 1976 to 2001, urban area increased from 22.481 km² to 75.257 km² with an annual increase rate of 2.111 km²/a. The driving-force analysis reveals that human activities of reclamation and population growth played a major role in oasis expansion in Manas River Valley. With the oasis expansion, a series of eco-environment problems such as sand invasion, pasture degeneration, soil saltization and land abandonment have become more and more seriously. The issues of how to improve the efficiency of water resource usage, protect mountain and desert environments, deal with saltization problems in oasis have become the most important research topics of oasis expansion and sustainable development over these oasis.

With a new satellite database that characterizes the significant land use and land cover (LULC) variations induced by the Western Region Development Strategy and the corresponding ecological engineering in China, a regional climate model is used to simulate their impacts on regulating the structure of summer monsoon system in East Asia and the relevant regional climate changes. The simulation shows that the East Asian summer monsoon might be enhanced because of the large scale LULC variations in western China, which is favorable to the water vapor transfer from the adjacent oceanic areas to the continent of China. The humidity increase in China continent can be partly attributed to the vegetation evapotranspiration but mostly to the water vapor transfer of the enhanced monsoon circulation. The integrated impact of LULC variations on temperature, wind speed as well as humidity are not only limited to the west part of China, but to the adjacent areas where the LULC does not vary. Neither is such impact limited to the atmospheric boundary layer; it can reach to a higher level of 850hpa (about 1500m) for humidity and wet hydrostatic energy and much higher for temperature, pressure and wind speed.

Terrestrial ecosystems, in which carbon is retained in live biomass, play an important role in the global carbon cycling. Among these ecological systems, vegetation and soils in deserts and semi deserts control significant proportions in the total carbon stocks on the land surface and the carbon fluxes between the land surface and the atmosphere (IPCC special report: Land Use, Land Use Change and Forestry, June 2000). Therefore, accurate assessment of the carbon stocks and fluxes of the desert and semi desert areas at regional scales is required in global carbon cycle studies. In addition, vegetative ecosystem in semi-arid and arid land is strongly dependent on the water resources. Monitoring the hydrologic processes of the land is thus also required. This work explores the methodology for the sequential continuous estimation of the carbon stocks, CO₂ flux, evapotranspiration, and sensible heat fluxes over desert and semidesert area using data from the Jornada desert in New Mexico, USA. A CO₂ and energy flux coupled model is used to estimate CO₂, water vapor and sensible heat fluxes over the desert area. The model is driven by the observed meteorological data. Its input land surface parameters are derived from satellite images. Simulated energy fluxes are validated for specific sites with eddy covariance observations. Based on the output of spatially distributed CO₂ fluxes, carbon accumulations over the desert area during a period of time is calculated and the contribution of the desert ecosystem to the atmospheric carbon pool is discussed.

Desertification outside the oasis and salinization inside are the main factors threatening the survival of oasis. The severity and extend of desertification and salinization depend on the spatial and temporal dynamics of soil water and salt concentration. A study was conducted to evaluate the effects of soil water and salt concentration on oasis stability near Fukang City, XinJiang, P. R. China. The dynamics of water resources for the region was analyzed using data from 1988 to 1998. Soil water content and salinity, ground water table and salt EC were investigated for months of May to September in 2000 and 2001. Changes of land use in the region were examined from 1987 to 1998 and causes of the changes were explored. There was no salinity difference among oasis, ecotone and sand dune. Ecotone was stable in terms of area and boundary because of the irrigation in the oasis supplied critical water needs for vegetation to the two adjacent systems. There were large salinity differences among oasis, abandoned land and desert grassland. For regions of abandoned land and peripheral desert of oasis, salinization had become a serious problem due to the salt accumulation on the soil surface and root zone from evaporated irrigation water. Because of the same reason, abandoned land increased dramatically from 1987 to 1998 in the lower reaches of Sangonghe River, especially inside of new oasis. Land salinization and second salinization were the major factors that threaten the survival of the oasis. Sound and effective plans for water use with proper irrigation and drainage systems are needed in order to minimize salinization effect and protect stable oasis.

The scientific community has been interested in the responses of vegetation to global change at regional and global scales. Many models have been developed to study the responses in terms of primary productivity. The ecosystem model, Biome-BGC, simulates the storage and fluxes of water, carbon, and nitrogen within the vegetation, litter, and soil components of a terrestrial ecosystem and can be used to quantify effect on net primary production (NPP) under different climate scenarios. This study was conducted in oasis areas along the Tianshan Mountains in Xinjiang, China with an arid climate. Ten sites were selected to test Biome-BGC model for its feasibility in the study areas. The model was proven not suitable to the desert ecosystem. After ecological and meteorological parameters were modified for each of the vegetation covers we applied the model to four sites that present agricultural, shrub, grasslands and mixed forest ecosystems. By using modified Biome-BGC model, we simulated the response of NPP with different land surface covers to four designed climate scenarios.

RAPD technique was applied to study intraspecific genetic polymorphism and differentiation of Suaeda acuminata populations in oasis-desert transitional zone in Fukang, Xinjiang. By analysis of RAPD data, higher genetic variability was found in the populations of S. acuminata, with a percentage of polymorphic loci of 98.9%. Both estimations by Shannon diversity index and by Nei's gene diversity index from RAPD data, it was found identically that about 72% of molecular variation existed within the subpopulations, while about 28% of which existed among subpopulations. Analysis of genetic identity, genetic distance and cluster analysis showed that genetic differentiation has taken place in the populations of Suaeda acuminata in oasis-desert transitional zone in Fukang, Xinjiang, China. The correlation analytical result between the soil factures and the genetic diversity indicted that there was a significant positive relation between genetic diversity and concentrations of Mg⁺⁺, conductivity (CO) and absorbed water(W) in soil, while there was no significant relation between genetic distance among subpopulations and geographical distance. Analysis of genetic identity, genetic distance and cluster analysis between the five subpopulations showed that genetic differentiation has taken place in the population of Suaeda acuminata in oasis-desert transitional zone in Fukang, Xinjiang. No correlation existed between genetic distance among subpopulations and their locations in oasis-desert transitional zone. Adaptation to its habitats and restricted gene flow among subpopulations may be a cause of genetic differentiation of Suaeda acuminata population in oasis-desert transitional zone in Fukang, Xinjiang.

In ecotone between oasis and desert of Qira, we choose different positions on bald dune, where vegetation was cut off completely. Then we observe and analyze microclimate, soil, plants, microorganism and water. In extreme arid zone, water is always the most important factor in restoring vegetation. Therefore, the possible positions for restoration are mainly in such places as oasis verges and old rivers with high water level. There, floods overflow easily. That is in the region with good ecological environment. It can not only supply enough water for the seeds' sprouting, but can offer the basic conditions for the young plants' extending, growing gradually and developing downwards deeply depending on ground water. In other else vast deserts, there's almost no environment fit for the vegetation's growing and restoring. After closing and rearing desert where all vegetation was cut, the essences of vegetation' restoration on dune is the van plants' initial condition on bald ground. Whether or not this restoration can go on is initially more dominated by physical environment than by biological environment of community. Terrain's important function lies in changing the distribution and composition of factors. This is active and important for restoring and widening the plants in desert. In the valley of dune, the configuration of water, heat and temperature is proper. Here, plants can easily touchdown and restore most quickly and the quantity of microorganism is most. The environmental condition on the top of dune is worse-high temperature, quick change and small vertical grads. The middle part is between them. Once the coverage degree gets to some extent, plants in turn affect the habitat. They prick up the variation of microhabitat at different positions. The features of plants per se must match the habitat. And only when they take advantage of the occasional opportunity then develop quickly, can they make an opportunity for ecesis.

The poor soil and the single vegetation in arid land are the important indexes of the site quality, which are revealed through the presence or absence of vegetation and patch distribution of different population in level structure. Heterogeneity of patch distribution is unchangeable in scale transition. The ability of anti-destruction and restoring is weak according to the site quality. So the young trees and the seedlings survived in the destruction of primitive vegetation restore to climax with a single dominant species through a long time. This provides a research basis on dynamics behavior by using the most famous population model in ecology. Control parameters in the dynamics model are analyzed comprehensively by using the combination of various control factors, the controlled changes are studied by the quantitative means. After debugging the value interval of various controlling factors , the value interval of the best index and of the dangerous index£¬this paper provides the actual value interval which is operable easily .The sample area for this paper is Fukang county in Xinjiang, whose longitude is E87°46'~88°44' and latitude is N43°45'~45°29' 8".

This article is about wilderness vegetation zone at Fukang oasis. We studied the time and space stability of vegetation community of wilderness vegetation zone at Fukang oasis, by regular researching materials of vegetation in the sample zone, inspecting the succession process and spatial distribution law of plant in the wilderness vegetation zone and using the improved method of contribution law, which was discovered and led into ecology study in the industry manufacture by French ecologist M. Godron, and in the process spread this method to the study of the spatial stability of community of vegetation. Firstly, we calculated all kinds of numbers and these kinds of cover degree on the vegetation community, and corresponded every kind of percentage on the vegetation accumulation and every accumulated relative cover degree, and drew scatter diagram on graph paper, and connected every spot by smooth curve. We connected a straight line between the two points on the coordinate axis,(all coordinate value equal 100) and the node of straight line, and curve is the point we calculated. According to this method, the kind of percentage accumulation and accumulated relative cover degree will be more stability when the ratio is trend to 20/80, which is the stability ratio of community. The researching result verified that stability of different plant community is different at wilderness vegetation zone of Oasis from the space. The community stability of wilderness vegetation of plant at Fukang Oasis is influenced by three factors such as species contest, environmental pressure and interference activity, even if the stability of the same edificator appears bigger difference.

According to the analysis of remotely sensed data and other multi-information of study area (its longitude: 113.5°-117° and latitude 39.5°-42°), the authors dynamically evolved desertification of Beijing and its neighboring areas, which the images were used in three different periods, 1987 TM, 1996 TM and the CB-1s CCD 4, 3, 2 bands of 2000, 4 orbits and 16 (CBERS-1) scenes (the resolution is 19.5m). By synthetically analysis, we obtained the area desertification distribute and evaluated space-time information. Based on the remote sensing interpretation and database of desertification multi-information efficiency distilled from geology, hydrography, anthropogeography, agrotype, vegetation and so on, we build up desertification dynamic simulation model with CA (Cellular Automata) theory and GIS (Geographic Information System) tool. Then utilizes this model to predict desertification development of Beijing and its neighboring areas. The result of the experiment proves that the model is effective to simulate desertification development in terms of macroscopic and microcosmic. The desertification of Beijing and its neighboring areas develop from west to the east, the southern edge is 72km to Beijing city where lies in the north of Jundu mountain crossing Yanshan with Taihang mountains, which prevents the development of desertification.

Desertification taking place in arid area is often related with vegetation deterioration in lower reaches of interior river. In the cause of it, the soil characteristics changed regularly due to less surface water and ground water lowing, which cause soil drying and salinizing. Through the analysis and comparison of soil characteristics in different sites with different desertification degree revealed the trend of soil water content, soil salinity, organic matter, soil texture, as well as changing trend from bog soil, meadow soil to adobe soil, halomorphic soil. These changes were accelerated as the vegetation ruined and lead to land desertification. The process of changing from autochthonous soil to adobe soil can be divided into different stages which differ in changing speed, i.e., the formation of climax soil will last long time. But, once its loss the stability, desertification will develop rapidly. Studying the possibility for the converse changes of climax soil is significant to vegetation restoration and should become a research direction in the future.

A multivariate analysis of desert-oasis ecotone vegetation in Fukang with 55x42 (plots x species) species matrix,55x4 environment matrix and 55x5 spatial coordinates surveyed in Fukang is presented. The results show:1) eight communities are identified from the 55 plots (Haloxylon ammodendron desert, Reaumuria soongorica +Haloxylon ammodendron desert, Reaumuria soongorica desert, Woody halophyte desert, Tamarix spp. shrub, Petrosimonia sibirica community, Suaeda corniculata community, Bassia sedoides + Bassia dasyphylla community). 2)plant species are classified into 5 ecotypes: arid type, osculant type, Halophyte I, Halophyte II,and secondary type. 3) DCA ordination is superior to CCA and DCCA on desert-oasis ecotone vegetation. 4) Variation of ecotone vegetation explained by environmental and spatial factors reaches 23.4%, among these the species matrix explained by non-spatial soil factors accounts for up to 11.5% of variation, spatial variation that is not shared by soil factors explains up to 11.6%, spatial variation interacted with soil factors up to 0.3%, 76.6% of undetermined variation remains due to biological and random factors.

Variation of environmental factors plays an important roll in the process of desertification. In this paper, taking Shule River as an example, the variation and correlation coefficient was calculated to evaluate the main environmental factors’ changes and its relation to the state of desertification. The results obtained indicate that the variations of factors including meteorological factors and human active factors are obvious. Since 80’s the annual precipitation and annual number of sandstorm days have been declining in a fluctuating state. The population and the area of cultivated land have been increasing. The correlation analysis shows that there exist positive correlations between desertification and population and area of cultivated land. The correlation between area of desertification and annual wind speed, annual number of sandstorm days is significant. In Shule River area, desertification state has more obvious relation with human active factor, comparing with meteorological factors.

The Gurbantunggut Desert of Xinjiang is in temperate climate zone and its eco-environment is very fragile. With the exploitation and development of the oil-gas resources and the implementation of the desert highway and great engineering projects in the Gurbantunggut Desert the impact of human activities on the eco-environment has been increasingly significant. We compared the physical-chemical properties and vegetation community characteristics of Sandic Entisols from two artificial longitudinal dunes with a natural longitudinal dune in an area of engineering construction. Our results show that the depth of rainfall infiltration and soil moisture after rainfall for the artificial longitudinal dune, which lost vegetation (especially microbiological crust), is remarkably higher than the natural longitudinal dune and soil moisture on the artificial dune was subject to greater rates of evaporation. Salt concentration in the soil profile of the artificial dune is relatively uniform and reflects the homogenous environment that has resulted from mixing the soil. In comparison, Sandic Entisols usually show marked variation in salt content with depth, this was observed in the natural longitudinal dune. The nutrient levels of the natural longitudinal dune are higher than that of the artificial longitudinal dune, which is related to the distribution, density and health of the vegetation cover. After installing checkerboards to fix the artificial longitudinal dune, we found that ephemeral plants rapidly colonised the checkerboard environment. However, the re-establishment of shrub and semi-shrub plants required some rehabilitation measures, such as sowing seeds. Although the pioneering vegetation lacks the diversity of the natural vegetation, it creates beneficial conditions to establish additional plant species. Thus, it can be seen that the desert vegetation and the physical and chemical properties of Sandic Entisols are greatly affected by the disturbance caused by engineering construction. However, our results show that if rehabilitation measures, such as fixing mobile sands and re-sowing seeds, are adopted during or soon after the construction period then the disturbed ecosystem still has some capacity for natural rehabilitation.

Desertification is one of the most serious environment and socioeconomic problems in the world and China today. Land of sandy desertification almost covers everywhere in Ejin Banner (County), Inner Mongolia. Using remote sensing method can expediently acquire some information such as desertification’s status, and effect of harnessing desertification. In this paper, ecological change situation from 1986 to 2000 in Ejina Oasis is researched. The result is followed: (1) Area of water body of Lakes in Northeastern Ejin Banner are distinctly reduced. (2) Area of the oasis is rapidly shrunk. From 1986 to 2000, the area is reduced 61.48%, average 4.39% annually. (3) Condition of oasis growing is declined. The oasis’s ecological environment trends to bad. Its main reason is what human activities exceeded the load capacity of natural resources such as water and land. By means of self-restorative ability of natural vegetation and human’s scientific conservation, that the oasis’s ecosystem maintains dynamical balance and the environment recovers is possible.

We used Landsat TM imagery and GIS to quantify the rates and patterns of landscape change of two different oasis ecosystems transects --- Fukang oasis and Yutian oasis in Xinjiang Uygur autonomous region, P. R. China. Human dimension is a major disturbance agent throughout the area and desert-oasis ecotone is also important. Maximum likelihood classification of satellite imagery identified landscape class types and changes among the landscape mosaics in two transects. Rate and pattern of the spatial and temporal of landscape change in two oases agricultural landscapes were detected at class and landscape level. The resulting landscape changes have a multitude of consequences; for agricultural production, landscape aesthetics, recreational and amenity values of the landscape, and for biodiversity. Results show that further intensification of the intensively managed landscape has led to an increasingly homogeneous, large-scale landscape featuring fewer boundaries. In contrast, reduced management in the oasis-farm system has resulted in an increasingly heterogeneous, small-scale landscape. The main pattern and key factors of dynamic changes of oasis-desert heterogeneity with frequent human’s activities especially land use were discussed. Because land use changes are triggered by socioeconomic forces in two oases, a through comprehension of historical change will enhance our capability to predict future landscape dynamics and devise effective landscape management strategies.

Using the results from interpretation of remote sensing images and synthesis of the historical literatures and maps, this paper deals with the river evolution of the Yellow River in Houtao Plain, Inner-Mongolia. Development of the south alluvial fan was stopped in the west Houtao Plain at the 2nd century BC; In the sixth century, the channel of the Yellow River, located at the north alluvial fan of the west Houtao Plain, migrated eastward, and it was divided into two branches, the south and the north, the latter was the main one; In the 18th century, the main channel of the Yellow River located at the north Houtao Plain moved to the south Houtao Plain; The North River silted up in the mid-19th century, meanwhile, the modern Yellow River was formed; From that time on, have no obvious changes happened. The evolution of the Yellow River is the response to geological structure, climate and human environment.

The oasis is a special landscape in arid areas, which plays important ecological role in arid and semi-arid geographic system. The matter, energy and information frequently exchange at its interface, and it is the primary human habitat in arid areas. The oasis ecosystem is fragile, with the intensification of human’s activity, the system will change more and more unstable. Based on the advanced technique of remote sensing and geographic information system (GIS), the goal of this paper is to develop an integrated system to dynamically regulate the oasis ecosystem to serve the sustainable oasis development. In this paper we describe the concept, structure, function and application of the oasis regulation system, and develop a group of models to explain and simulate supply-demand process of water and soil resources. The water supply model can calculate the available water resources of ground water and surface water. The water demand model can estimate the total water demand including agricultural water, ecological water, and other water demand. The system balance model can balance the water demand and water supply by regulating the usage of water resource and land use structure. The system is established on the base of a database including topographical, meteorological, hydrological, land use, social economic and some other special data, and multi-temporal remote sensing images are dynamic data source. The system will be used for studying the relationship between water resource usage and ecosystem development in oasis, and which will be helpful for oasis planning, management, and monitoring to realize its stable and sustainable development.

Environmental evaluation and planning is a hot point of the relative science research nowadays. So the work is carried out in the Dingxi prefecture, a typical loess gully-hilly region of the semi-arid regions. The AHP method is used to evaluate the characteristic, quality, and degree and potential in use of the regional ecological environment. Then some suggestion on the ecological renovating, restoring, and planning were presented. The factors were selected according to our data resources and the factors weight is defined. The results indicate that using AHP model, the environmental evaluation can be performed in the loess gully-hilly region in northwest of China. In the study area, the quality, and degree and potential in use is not so good in the most of the study area. On the bases of quality evaluation, the environmental planning was developed.

MODIS image products were used to examine dust and sand storms occurred in Tarim Basin and identify major land cover types that may have contributed most to the recent severe dust storms. The near daily global coverage and multispectral capability of the MODIS sensors have made MODIS image products one of the best satellite observation data sources for monitoring large-scale Earth surface features and phenomena. The Level 1-B granule image quicklooks provided by the MODIS Atmosphere Science Team have proved sufficient for tracking dust storms in Tarim Basin. Within the last twenty-two months, Tarim Basin was covered by different scales of dust or sand storms almost year round. However, the basin-wide dust or sand storms were rare and they occurred mostly in March and April, when soil surface protection is the poorest and wind speed is the highest. As indicated by the compiled image quicklooks series, all dusts and sands were derived from within the basin. Once suspended in the air they were confined to the basin by the high mountains bordering the Basin. Only a relative small amount of dusts were exported to the east when they were associated with strong cold frontal systems. Analysis on the land cover type maps derived from full-resolution and cloud free MODIS Level 1-B radiance images suggest that the former Tarim River delta complex and current and past fluvial plains are the newest additions to the source areas of dust and sands. These two land cover types deserve the highest priority in the restoration of desert ecosystems effects in the region.

Remote sensing(RS) technology, which has made great progress in many applied fields, can provide an efficient means for active identification of grassland degradation. In this paper, we used the Landsat TM images in 1980’s and 2000 to monitor the dynamics of grassland degradation in Shandan County where was famous with its army horse feeding and the important self-restraint regions of soil and water in the upper Heihe basin in Northwest China. By integrating RS and Geographic Information System(GIS), we calculated the amounts and the changes of grassland types during the past 15 years. Using satellite monitoring and retrieval means to get the productivity of grassland, analyzed the carrying capacity of livestock, and classified the grassland into 4 degradation levels and created the grassland degradation maps. Then, we use the landscape ecology principles to design the recovering planning of the corresponding degraded regions. At last, we promoted the corresponding strategies to restore the different degraded grasslands in Shandan County. This approach to dynamic monitoring of grassland degradation and the retrieval of grassland productivity is a fully digital operation, so it makes best use of computer and GIS to manage, display, query and map the grassland degradation data.

This paper introduces the use of Remote Sensing (RS) technology and GIS, combining with multidisciplinary methods, at the Zhangye and Jiuquan Oases in northwest China. Results show that: The integration of RS and GIS, Landscape Ecology, Settlement Geography, Community Ecology and social science is an efficient way to analyze landscape pattern and human impacts; The combination of Human Impact Index (HIM) and Human Pressure Index (HPI) can illustrate the influencing intensity of human beings explicitly; Nearest Distribution Pattern Index (NDPI) and spatial neighboring proportion can describe landscape pattern superior to partial traditional indices. NDPI is a potential index to replace Contagion. The neighboring proportion can reveal the neighboring relation more clearly than the Interspersion & Juxtaposition Index; The conclusions obtained from the Landsat TM data are well in accordance with the field survey and multidisciplinary analysis: Farmland and settlement are the key components in the both oases; At the patch types level, the distributing pattern is quite complex in the both oases. At the landscape level, the both oases are distributed randomly; Because of higher population pressure, more developed agriculture and communication, and higher density of manual corridor, the spatial pattern is more homogeneous and the human impacts on Zhangye Oasis are stronger than Jiuquan Oasis.

The Xilin River Basin, Inner Mongolia, China is dominated by grassland ecosystems. Human activities (e.g., crop cultivation, livestock grazing, urban development, construction of infrastructure) in the basin have resulted in substantial changes in land cover, particularly since late 1980s. In this paper we used Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper Plus (ETM+) data to study the land use/cover change in the Xilin River Basin, Inner Mongolia. High-quality (less than 10% cloud cover) TM/ETM+ images (WRS124-29 and WRS124-30) acquired on four different dates (July 31, 1987, August 11, 1991, August 27, 1997, and May 23, 2000) were collected for this study. The Xilin River Basin is within two Landsat images (WRS124-29 and WRS124-30), and therefore, we mosaic WRS124-29 and WRS124-30 images and then cookie-cut it for the Xilin River Basin after preprocessing of the images. Based on the vegetation and land use characteristics of the basin, a hierarchical land cover classification scheme was created, including identification of major grassland types (e.g., Stipa grandis, Leymus chinensis). Then we conducted image classification using both supervised and unsupervised classification methods. Ancillary data such as vegetation map, soil map, topography maps, field survey data and literature of the Xilin River Basin were used for interpretation and labeling of spectral clusters as well as accuracy assessment of land cover classification. Finally, the resultant classification results of those four dates were used to quantify the spatial extent of land use/cover change in the basin and to develop the transitional matrix of land use/cover changes since 1987. The results derived from this study could be linked to biogeochemical models for assessing the consequence of land use/cover change on carbon and nitrogen dynamics of terrestrial ecosystems in the basin.

In addition to investigate the rainfall over the Tibetan Plateau, Microwave Imager observations on board of the satellite Tropical Rainfall Measurement Mission (TRMM) have been also used to retrieve land surface parameters, such as sur-face temperature (T_e), vegetation water content (W_c), and volumetric soil surface moisture (M_v). A three dimensional Look-up Table (LUT) scheme, by using one band brightness temperature, a 'Polarization Index' (PI), and an 'Index for Soil Wetness' (ISW), was developed for this purpose, which can retrieve the three basic parameters T_e, W_c, and M_v simultaneously. Considered that there are still clouds as well as heavy rainfall disturbance in deriving surface parameters over the Tibetan Plateau, 10-day composite TMI images were used. For the five months from May to September 1998, the distribution of surface parameters of each ten days on the mesoscale intensive experimental region of GAME-Tibet was evaluated. The results were compared with field observations; particularly, for the most concerned surface soil moisture, the results are quite acceptable. 3-D LUT is an easy and effective method to be used in the passive microwave remote sensing.

Remote sensing used in the context of global information systems has enormous applications within archaeology. This technology enables the discovery of new archaeological features and promotes an understanding of the relationship between ecosystem and cultural dynamics. Archaeologists are able to add a time dimension to 'creeping environmental changes' that other areas of scientific inquiry concerned with climate change often lack. Remote sensing and other aerial prospecting has been used successfully to model land use and population expansions during relatively recent archaeological eras, such as the Bronze and Iron Ages. Although satellite image databases exist for numerous areas of the New and Old World, very little research has been conducted in Central Asia or western China. This region is historically significant because of its position along the important trading route called the Silk Road. The purpose of the present research is to investigate another poorly understood period of human history that would benefit from the application of remote sensing and associated ground truthing techniques. The migration of hominids out of Africa during the late Pliocene/early Pleistocene and their subsequent colonization of north-central, east, and south-east Asia is relatively well documented in the archaeological record and marks the beginning of the long-term process of human impacts on the region. However, the trajectory of dispersal of Homo erectus, Neandertals, and early modern humans and the ways by which ecosystem vagaries affected this dispersal across Eurasia is unknown. Our purpose is to summarize what is currently known about the geological indicators of ecosystem changes that remote sensing techniques provide and how ecosystem variables may allow us to model human migration as that of an invasive species through this important geographic crossroads of the Old World.

By recognizing the issues related with drought, desertification, diversity and development (i.e., the 4Ds) in arid and semi-arid lands in Central and Western Asia, The need of developing an interdisciplinary and environment-oriented education and training program, named “Desert Affairs Program”, is discussed. Its aim is to train present and future researchers, policymakers and educators for dealing with issues related to environmental science, impacts, policy, economy and ethics in arid and semi-arid lands in Central and Western Asia.

Gurbantonggut Desert, located at the center of Jungar Basin, has an area of 48,800km², which is the biggest immovable and semi-immovable desert in China. There is profuse oil-gas resource. Along with the oil-gas resource exploiting, more and more engineering has been built in the center of the desert, such as the desert highway and the oil fields and so on. However, aeolian environment in the Gurbantonggut Desert has a great impact on the engineering building and engineering safety. There are more than 20 gale-days per year in the center of the desert, and the main directions of the effective sand-moving winds are NE and NW, and sometimes the strong SE winds occur in the east part of the desert. The effective sand-moving winds appear mainly between April and September, which occupies 80% of whole year. It is obvious that the huge transport potential formed by the strong wind force badly endangers the engineering construction. Primary shapes of sand dunes in the desert are longitudinal and dendritic dunes, which occupy 80% of total area of the immovable and semi-immovable desert. The sand grains of the desert are coarser, and the average grain size is 0.2~0.22mm and 0.15~0.17mm in the southern and the northern part of the desert respectively. The vegetation coverage is 15~50%, and also there is about 85% of the total sand surface to be covered by the microbial crust. In this case, most dunes are fixed or semi-fixed, only on the top of the dunes existing about 30m mobile or semi-mobile sand belts. That indicates that the fixed or semi-fixed sand surfaces are dominant in desert, which prevents blown sand from doing harm to the engineering construction. Meanwhile, with the engineering construction, the fixed or semi-fixed sand surfaces are easy to be destroyed in the desert, which threatens the engineering construction and safety greatly. In general, there are about 1m thick moist sand layers in the desert and the moisture content has great changes in time and space. The moist sand layer in the desert plays an important role on the ecological rehabilitation and the aeolian disaster control in engineering disturbance areas.

MaNaSi River wetland lies between diluvial fan and alluvial plain of MaNaSi River system ,about 300 km² squares. It is a typical inland river nature wetland in arid areas. local people have done massive construction of ecological engineering during more than fifty years. The mainly achievements are the twelve reservoirs which have formed a large-scale cluster of wetland reservoirs. They link MaNaSi river with man-made oasis and turn a single headwaters and static function wetland into a powerful function dynamic wetland which has various headwaters. The wetland has powerful preventive function: It can prevent wetland from shriveling and retrograding, can prevent or control flood, fight drought, keep ecological balance of wetland and achieve sustainable development, and has a capacity storing enough water and conserving water, can conserve headwaters well because of its particular hydrogeology and condition of ecology. The wetland can completely resolve uncoordinated contradiction between agriculture needing water and river storing water by cluster of wetland reservoirs of adjustable function. It turns a nature wetland into a new wetland which has fully functions, diversify ecology, sustainable development through construction of ecological engineering..this wetland is a model of construction of ecological engineering on inland river wetland of arid areas

Substantial changes in land use and land cover dynamics have occurred during the last several decades in western China, which include deforestation, desert expansion and intensified land use due primarily to an increasing population, industrialization and agricultural development. These changes have had great impact on ecosystem functions at both local and regional scales. The Gobi Desert area near Zhangye City, Gansu Province, P.R. China has been blamed for the frequent occurrence of dust and sand storms in remote areas such as the Beijing and HuaBei regions. A study was conducted to quantify the land cover dynamics using remotely sensed images from the Landsat MSS, TM and ETM+ sensors for the region near Zhangye city within the Heihe River watershed. The regional landscape ecology for 1977, 1989 and 2002 was quantified using both traditional classification techniques as well as the continuous field method, the latter being a measure of land degradation severity. These remote sensing products were used to quantify the magnitude of the land use and land cover changes over 25 years. The results indicate that agricultural areas increased from 6% to 15% due to increased human activities. At the same time, other land use areas decreased because of conversion into agriculture lands. Land degradation in the region was obvious as evidenced by the increase in lower vegetative areas (0 to 10% fractional vegetation cover) and disappearance of high vegetative areas (90% or more). One of the most noticeable changes is that Zhangye city expanded rapidly during the last 25 years and practically doubled its urban territory.

In the semi-arid and arid region in northern Shaanxi Province, 11 TM images were selected as information source. On the platform of ERDAS IMAGINE, based on the classification signatures established according to the training fields by in situ surface investigations and with the support of various information from GIS, the computer-supervised classification was used to extensively investigate the surface eco-environmental factors, such as the vegetation, land use type and vegetation coverage. The total area covers 84000 Km². The average precision of classification is 83.78%, Kappa coefficient 0.819. Thematic maps have been compiled at the scale of 1:100,000. The features of surface eco-environment in this area are briefly analyzed on the basis of the remote sensing investigation results.

There continues to be controversies among scientists whether humans are contributing to land degradation (desertification) in arid and semi-arid regions of the world. One area of considerable interest is the Gobi desert of central Asia, which is one of the largest deserts on Earth. The Gobi Desert is of particular value for addressing this question because it is divided by two countries that employ vastly different land management practices. Land use in China is high intensity and in Mongolia land use is of low intensity. In this study, climate and satellite remotely sensed data from 1982-1999 were used to investigate interannual variations in the areal extent the Gobi Desert boundary. Our results show substantial year-to-year variations in the size of the Gobi desert which was strongly correlated with annual precipitation (R² = 0.81, P<0.000). Based on results of logistical analysis of the climatic and remotely sensed data, an actual evapotransporation threshold of 180 mm per year was identified as the factor for discriminating between areas of desert and steppes within the study area. Correlation values between the areal extend of the desert and climate data were highly significant for study areas in both Mongolia and Inner Mongolia, suggesting that at the scale of our study, human activities contributed little to interannual desert boundary fluctuation. Due to data availability constraints, we were only able to examine satellite imagery over an 18- year period which did not include both a wet and dry cycle for this region. Therefore, a more complete understanding of Gobi Desert boundary response to interannual climatic variation will require studies extended over a longer time period.

In this paper, the author make up a way of dividing whole remote sensing image into sub images to classify the type of vegetation. There are different types of vegetation in different geographic unit. So according to geographical region feature in a remote sensing image, the whole image is divided to several sub images, the types of vegetation in a sub image is less than in a whole image. Types of vegetation in a region graphic is easy to be showed, the threshold of classifying has a wide scope, with the assistance of Digital Elevation model (DEM) and slope maps, classification accurateness was improved. This way was applied in Xinjiang north, we hold NDVI (Normalized Difference Vegetation Index) image as data resource, dividing whole research area into four regions: Altai grassland region, West Zungaer region, Zhaosu region and East Tianshan region. Different classifying standard was used in different region, and then using GIS software together four regions into a whole classified image. Because this method was grounded on knowledge, the classification result of vegetation in Xinjiang north was improved to 89.33%.

This paper presents the results of an intercomparison study of data fusion methods. Three data fusion techniques, based respectively on the Daubechies wavelet basis method, the IHS transform, and the Principle Component Analysis (PCA), are compared with each other. According to the data set we used in this study, the Daubechies Wavelet Basis method is far more efficient than the PCA and the IHS transform, It thus establishes the advantages for data fusion, formally called multiple resolution analysis. This method is the best among the three for image sharpening and for maintaining the information of the original data. We conclude with the result from this study that the Daubechies Wavelet Basis method has the largest application potential for merging the spatial and spectral characteristics of multiple resolution remote sensing data with high efficiency.

The crown canopy interception amount to precipitation has nearly relationships to forest species, density, coverage degree and heights etc. Difficulties to analyze crown canopy interception amount to precipitation are attributed to the widespread forest areas with complicated plants species and sparse precipitation observation stations in East China. Resolving these problems are the keys of the study. The author took Guixi County that is located in Jiangxi Province in Southeast China with subtropical climate as an experimental area to study the variation features of forest crown canopy interception to annual precipitation involved trees species, altitudes and geographical locations applying RS and GIS technology, which can provide scientific basis to dynamic research on hydrology ecological capacities of forest.

With the successful launching of the new generation satellite of EOS Terra, its Moderate Resolution Imaging Spectroradiometer (MODIS) data has more advantages in comprehensive research of land, ocean and atmosphere. ALso it can be used in disaster monitoring and losing assessment. This article focuses on the discussion of using Terra/MODIS data to study sand-dust information quantitative retrieval method. The conclusion is that MODIS data can be used to study the quantitative retrieval of sand-dust information and the study scenario has certain feasibility. The study contains of selecting the characteristic spectrum bands of sand-dust information; separating sand-dust information from the background and enhancing the weak information of floating dust, raising dust, etc. Theory basis of quantitative retrieval method are remote sensing quantitative method, atmosphere radiative transforming and visibility theories. Data pre-processing is also necessary. Retrieving of sand-dust aerosol optic thickness is more difficult and also the key problem to resolve. Case study is necessary and should be used to support the quantitative method. The study can provide the theory basis and technique support for sand-dust disaster forecasting monitoring and preventing.

Much attention is focused on Land-use / Land-cover changes (LUCC) in recent years in the field of geographical studies, not only because it is one the most important contents of global environmental change, but also for the reason that it can affect terrestrial carbon cycle greatly, which plays an important role in warming the earth. Together with some data collected from the State Statistical Bureau and the State Land Administration, remotely sensed data (NOAA / AVHRR Imagery) is also used to study land-use change in east China during the last 20 years. It is clear that the land structure changes greatly in this period. More important, the farmland, grassland and forest have been changed more than any other elements. In the meantime, impacts of land-use change on land-cover change in the area are also analyzed by studying change of the Normalized Difference Vegetation Index (NDVI). Finally, it is estimated that based on such changes, the net primary productivity in east China during last 20 years may increase. The preliminary analysis shows that a relative steady increase in terrestrial net primary productivity is acknowledged. In another word, it seems that vegetation has sequestrated more carbon these years in east part of China.

On the basis of the image database and vector database of the Keriya Oasis, the paper primarily studies the changes of the land cover of the oasis of Keriya during the last decade using remote sensing data and geographic information systems. In contrast to the data of the latest three years’ fieldwork, the environmental changes and the desertification degree of the study area have been analyzed. The results are relevant to the sustainable development of the west arid area.

In this paper, the data of spectral observation and the grass yield of natural grassland in the north of XinJiang from 1991 to 1994 are used for analyzing the spectral vegetation index characteristics, studying the relationship between the ground spectrum and satellite remote sensing data and establishing the grass yield monitoring model and estimating model of natural grassland in the north of XinJiang. Based on the relation between the spectral vegetation indices and the satellite greenness value, satellite remote sensing monitoring model can be established. Then, the satellite remote sensing monitoring models were established.

The water area of the Ebinur, Bosten and Aydingkol lakes, the main lakes in Xinjiang, China, during the period of 1999~2002 is dynamically monitored by using the data of American NOAA and EOS global observation satellites and Chinese FY-1C meteorological satellite. The monthly water areas of the lakes during the period from March to October are calculated, the change characteristics of the water areas of the lakes in the watery and dry seasons and the intermonthly change characteristics are preliminarily understood. The results show that the watery seasons of the Ebinur, Bosten and Aydingkol lakes are the periods from November to April, from December to March, and from January to April, and their dry seasons are the periods from May to October, from April to October and from May to November, respectively. The factors influencing the water area of Ebinur Lake are analyzed by combining the climatic factors. The results show that, except the artificial water consumption, the factors directly influencing the water area of Ebinur Lake are mainly the depth of snow cover on the riparian areas in winter, seasonal precipitation, evaporation and sunshine duration. The strong winds from Alataw Mountain Pass impact seriously the ecological environment in the Ebinur Lake region and its basin. Some practical and effective measures should be taken for controlling the sand drift and for protecting the environment of the lacustrine wetlands in the arid areas.

In this paper, we report some correlation analysis results between hyperspectral data in the spectral range of approximately 350nm-935nm and LAI of rice. Hyperspectral measurements were taken using an Analytical Spectral Devices (ASD) FieldSpec UV/VNIR Spectroradiometer at the experiment farm in 1999 and 2000.The potential of hyperspectral data for estimating LAI was evaluated using univariate correlation method with different types of predictors: original and the first-order derivative spectra, vegetation index (VI) based, spectral position-based, area-based predictors. The 6 VIs were constructed from the green-peek and red-well spectra bands; spectral position-based, predictors consisted of parameters extracted from the blue, yellow, and red edges, the green-peek and the red-well; area-based variables were calculated as the sum of the first derivative values at each of the three edges. Results showed that for univariate correlation analysis, the better results were obtained for LAI. The best LAI was obtained with the area-based predictors in prediction models for LAI. In univariate correlation analysis, it seems that only wavelength at maximum value of 1st derivative within red edge (Wr), reflectance at green-peak and at red-well, and their VIs may be employed to predict LAI, and betterR² valued were obtained from the maximum first derivative spectra of blue edge (SDb) and red edge(SDr). In general, the results obtained from the accuracy assessment the best predictors are area-based ones, the VIs of SDb and SDr. Results from the correlation analysis showed that in the regions of the "three edges" for estimating LAI, sum of 1st derivative values within red edge was the most effective, sum of 1st derivative values within blue edge was the mere effective, sum of 1st derivative values within yellow edge was not effective.

Marked by high efficiency, multiple channels and low cost, meteorological satellites have the applications extending from the use only in a meteorological context to quite a few scopes of research and operation. This paper introduces the establishment of statistical models between altitudes of stations at different latitudes/longitudes and corresponding NOAA/AVHRR remote sensing data to obtain the terrain altitudes in Ningxia and its surroundings whereupon the heights of different parts of Ningxia are found, with the results applied to the retrieval of spring soil moisture, thereby leading to the construction of soil moisture retrieval models from satellite data and altitudes for real-time monitoring soil moisture. Results show that it is successful to make verification of satellite-data calculated altitudes against measurements, which, when introduced into the soil moisture retrieval models, improve the accuracy to greater extent. On this basis we developed the operational models for remote sensing based spring soil moisture monitoring in the target region that are run in an easy, quick and visual way, thus providing an efficient means of farmland soil moisture/dryness distributions monitoring.

In the recent 50 years, the exploitation of mineral products and water resources in XinJiang has developed greatly, which contributes a lot to the development of economy and society in the region. However, the ecological environment problems caused by it have already aroused great attention. It is also an urgent mission for the researcher to solve the problems of harmonizing the relation between the exploitation of resources and the sustainable development of ecological environment. Xinjiang, which lies in the middle of Eurasia, is one of the aridest areas in China, its ecological environment is vulnerable. For a long time, the irrational exploitation of oil and gas resources, solid mineral products resources (such as coal resources, nonmetallic metal and precious metal resources) and water resources has already brought about serious ecological environment problems.

In implementing China Western Development, there is no doubt that we should pay more attention to studying the sustainable development in arid north-west regions because those areas are backward in economy and hostile in natural environment, and have strategic positions to promote the real development of western regions. Of those regions, Xinjinag has even strong potentials to have a great impact on different factors of sustainable development because it is more inland than any other western region. Particularly, it is essential for us to take advantage of even more flexibility which dominates the means of adjustment and control of water resources utilisation and management, and to give a strong back-up in government decision-making. This paper focuses on Xinjiang water resource status to propose four characteristics in Xinjiang water resources and to point out relevant existing problems. According to the internal and external environments of China Western Development, the paper analyses the impact of developing trends in Xinjiang water resources on agriculture planting, manufacturing industry production, urbanisation, ecology evolution, and natural environment changes. In addition, this paper probes several problems on supply and demand of Xinjiang water resources. Lastly, the paper relies on the perspective of sustainable development as guidance, and on the perspective of water resources value as a basic theory to propose the relevant suggestions and countermeasures in the relationship of Xinjiang water resources development to societal and economic development.

The Tarim River Watershed consists of the headstream and trunk-stream zone, and the water consumed by the human and ecosystem in the trunk-stream zone is basically controlled by the hydrological process in the headstream. This process is random. Because the serial of hydrological observation data is short, it is necessary to analyze the uncertainty of hydrological system in order to obtain integrated hydrological information. The probability statistics is a method which frequently used to deal with this problem. But P-III Frequency Curve in common use is not perfect. And the multiplication frequency curve type III, based on the multiplication theorem of probability and the attribute of median, have such qualities as fitting the calculation of non-instantaneous value( for annual runoff quantum), no J-shaped & Z-shaped distribution and resistibility and robust. Using the X-III₂ multiplication frequency curve, the 5 long data serials (n=14800) are simulated with the observed data through 35 years of 5 hydrological stations in headstream zone. The statistic analyses of these analog serials are made. The analytical results show that the hydrologic and water resource system in headstream zone is stable. This conclusion will help the exploitation and utilization of water resource in the basin.

The continuing rise in atmospheric CO₂ is considered as a main cause of the future changes in global climate. Predicted climate changes include an increase in mean annual air temperature and alterations in precipitation pattern and cloud cover. Net primary productivity (NPP) measures products of major economic and social importance, such as agricultural crop yield and forest production. It is important to understand the response of vegetation to the possible climate changes. While the Global NPP is hard to be measured directly, its global spatial and temporal dynamics can be investigated by a combination of ecosystem process modeling and monitoring by remote sensing (RS). NPP has been linked to climatic patterns by approaches ranging from simple correlations to sophisticated simulation models. This study was conducted in a range where the productivity and climate exist along an east-west transect in northern China. We used modified Common Land Surface Model (CLM) to simulate the NPP combined with satellite data and assessed the response of NPP under different climate change controls with different land surface vegetation types in study areas. The feasibility of the CLM model was tested and parameterized based on the ecological characteristics. The response of NPP to increased temperature was more sensitive to the doubled CO₂ climate because the temperature is the limited factor to vegetation growth in study areas. The responses of NPP to different climate controls were also influenced by different vegetation types and ecological characteristics.

Oases is a special ecosystem formed in arid climate and hungriness environment, in which resident, water and soil are the principal factor and exchanges of materials, energy and information are the main functional characteristics. The oases regions in central Asia are not only the basilic cradle of civilization of human beings, but also the important strategic places in world growing awareness of the potential benefits. We choose Keriya River Basin oases in south of Xinjiang as a case to study critical controlling of Oases Evolution, Based on the theories and methods used for environmental geology, physical geography, land resource research, and oases ecology. This study try to indicate the essential factors driving the oases ecosystem and the interactional dynamic mechanism in different scales and levels, confirm the optimal equilibrium aggregate of harmonious development between Population, Resources, Environment and Development, and establish the critical controlling pattern of sustainable development. We advance the indicator system to research the evolution of the PRED System of oases in Keriya River valley oases, in basis of the information derived from the field investigation and local materials. According to inquisitional result based on technical support of Geographic Information System (GIS) and Remote Sense (RS), the comparisons and analyses are carried out in land use at the upper reaches, vegetation change in the middle reaches, and desertification at the lower reaches, which narrates the regulations of Keriya River Valley oases land cover dynamic change. The main land cover types represent distinct characteristics of the local place. On the basis of field survey and statistical data, we use ARCINFO software to preprocess these data and the 2 TM satellite images. Through analyzing these images resulting from post-classification compare, we sums up the concrete quantificational dynamic distributed data of 13 land types covering a span of 15 years and regulation of the local ecological environment system. It finally points out that the trend of Keriya River Valley oases desertification expansion is mainly related to two important reasons: impact of natural environment and impact of human activities. In order to improve the local ecological environment, people inhabited this

North China Plain covers an area of 140,000km². Because of groundwater overdraft for many years, the level is rapidly fallen, shallow water-bearing bed seriously drained, and deep one appears many large-scale drawdown cones. The shortage of groundwater resources cause a tense situation in urban, industry and agriculture water-supply. Under the situation, it is a urgent to us to investigate and evaluate the groundwater useful Potentials. The north part of Taihang Mountain front plain is chosen as a test region using remote sensing technique. Landsat-7TM image and aerial colour infrared image are used in the work. Through a comprehensive analysis and study of satellite and aerial images and other related data, the following results are obtained. (1)The alluvial and flood deposit fans are exactly delimitated. (2)The spacial overlapping relations between different fans are defined.(3)Palaeochannels are interpreted in detail. (4)Ten shallow-buried areas of groundwater and one groundwater discharge are discovered. (5)All surface sediment types and all kinds of microgeomorphic bodies are interpreted. (6)6 rich groundwater areas are definited, and two of all are confirmed by a geological examination.

Based on meteorological data of the recent 40 years, the long-term changes of sandstorms in China’s Xinjiang region were analyzed. The frequency and the scope of influence of sandstorms that occurred in Xinjiang have decreased during the 1990s. In fact, with the warming of the climate, a wet trend was also obvious. By comparing the relations between the long-term changes of climate and sandstorms, we found that there may be some synchronous connections between them. On the other hand, we noted that increased population and livestock pressures on marginal lands around the desert have accelerated desertification processes. While desertification has received tremendous attention by political leaders and publicity from the news media, there are still many things that we do not know about the degradation of productive lands and the expansion of deserts. Clearly, the relationship between desertification processes and the occurrence of sandstorms is tight.

Xinjiang located in the center of Eurasia and is far away from oceans. It features arid and semiarid continental climate, large area and complex terrestrial. The ecological system in Xinjiang is very fragile and changeable. Water resource management is critical to the development of local economy, especially to agriculture and livestock. Droughts occurred frequently in Xinjiang. On the other hand, mountains floods erupted in some years. In these years, snow melted rapidly because of mountains precipitation increasing abnormly and temperature getting higher. In these cases, mountains floods occurred easily. We have some experiences on forecasting these kinds of floods, for example, if 24h accumulated precipitation exceeds 25mm within 200km in mountains area, floods may happen. Another interesting fact is that we monitored through satellite images that there are heavy precipitations in the center of Tarim basin, this is very important to local water resource management. So accurate predictions of drought and flood disasters are very important to water resource management. This paper reports some research results of rules of drought and flood occurring and some forecasting methods

Modern climatic viewpoint integrated common understanding and recognition of modern climatology separately. It reaches "viewpoint" and becomes new conception after epurating. Modern climate theory includes: The viewpoints of climatic system, climatic resource, climatic environment, climatic change and climatic hierarchy.

Qira Oasis lies in the southern region of the Tarim Basin, and on the northern slope of the Kunlun Mountains. It is one of the areas which show the obvious evolution of an ecological environment, and has been intruded upon by human activities in the last 50 years, so it has became a target area for researching, exploiting, and utilizing water resources in the oasis. Based on groundwater formation in the Qira Oasis, this paper will study the prosess of yearly and seasonal groundwater variation and analyze the relationship between groundwater variation and the eco-environment of the surface.

Xinjiang is an agricultural region in arid climate zone of western China. 58.9% of the river water and 23.1% of the groundwater are used to irrigation regions for agriculture. The water for natural ecosystems decreases constantly. The water utilized for human being and for nature is conflicting. For irrigation water it is existed that high water consumption with low economic return. The water utilization efficiency is 52.6% and the return for per cubic meter water is only 0.15 US Dollar. There are four serious ecological problems related with the improper water utilization in Xinjiang, i.e., the land desertification, the soil secondary salinization, the lake drying and water quality worsening and the vegetation degeneration. In this paper, five countermeasures for sustainable water utilization are presented.

Real-time observational data including 500hpa charts and surface charts from 1995 to 2000 after being analyzed indicate the dust storms caused by cold air crossing the mountains in Xinjiang were classified into two types according to the paths which they had taken: the westerly path type and the northerly path type. The synoptic causes and forecasting indexes of these two different types were pointed out combing research results and forecasting practical experiences. And a typical case of the westerly path type occurred during May 4-6 in 2000 was given to show the weather process, synoptic causes and forecasting indexes. Also the analysis of three typical dust storms of the northerly path type occurred during July of 1996 reveals how cold air crossed the mountains down to the Taklimkan Desert and caused dust storms in summer. The common opinion is refuted that in summer cold air is weak and severe dust storms caused by cold air crossing the mountains cannot occur.

This paper attempts to solve the doubt that whether climate factors motion could lead to the variation of water area across the Tarim Basin on decadal scale. NOAA/AVHRR NDVI digital images and monthly climate data of 25 standard stations were used from 1992 to 2001 in Tarim Basin. Relationships between water area and climate factors were analyzed in temporal and geographic variation. The result shows that the general tendency of the variation of water area is not sensitive to climate factors, which confirms that typical arid climate and irrigating agriculture affect the variation of water area across the Tarim Basin on decadal time scale, and short-term climate factors do not affect it significantly.

In the paper, the three outstanding features of climate change in Xinjiang for the recent 40 years are identified. Their causes are discussed primarily from two aspects of natural change and factitious influence. Results are as follows: (1)The warming trend of winter mean temperature in northern and southern Xinjiang are resulted from the controlling of macroclimate regularities of winter warming in The Northern Hemisphere and the local influence of factitious factors, the former is more important than the latter. (2)The increasing trend of summer precipitation in southern Xinjiang may have little to do with the change of macroclimate background, but mainly have to do with human activities, especially with increasing of real evaporation in oasis area, which are result from both the area under cultivation (or oasis) enlarging continually in southern Xinjiang between the south foot of Tianshan Mountains and the north foot of Kunlun Mountains and the amount of drawing water from Tarim River increasing continually. Furthermore, the warming trend of summer in southern Xinjiang for the recent 40 years coinciding with The Northern Hemisphere also helps to increase evaporation intensity, to form the increasing trend of real evaporation amount, and results in the increase of summer precipitation. But this is less important than the increase of available evaporation water amount and evaporation area that result from the acreage under cultivation (or oasis) enlarging. (3)The variability of annual mean temperature in Tianshan Mountainous area is the greatest, which maybe have to do with that the annul difference of early or later of forming or smelting, thick or thin and cover extent of seasonal stable snow is largely in the area.

The relationship between the change of stream flow and the human activities in the Tarim River watershed is investigated based on the observed data collected by 13 meteorological stations from 1961 to 2000 and 8 hydrologic stations in the watershed. It is preliminarily attempted to quantify the impact intensity of the human activities. The influence index of water consumption is put forward, and the impact trend of human activities to the mainstream of Tarim River is analyzed. It is considered that the increase amplitude of the impact of human activities was the highest during the period from the 1970s to the mid-1980s, and the increase amplitude of human activities has been slowed down to some extent during the recent 10 years. Moreover, the temporal and spatial distribution characteristics of the climate change, sand-dust storms, floating dusts and strong winds in all the areas of the source streams and the mainstream of Tarim River are compared and analyzed. It is pointed out that the precipitation in the Tarim River watershed has increased since the 1990s, especially in the areas of its main source streams, and the occurring days of sand-dust storms, floating dusts and strong winds have obviously reduced. The possible relationship between the climate change and the human activities is also discussed.

Global warming during the last century is less doubled internationally. The warming trend in the past 20 years is especially distinctive which makes the phenology and productivity of vegetation change remarkably. Based on NOAA/AVHRR data, combined with the observed meteorological data, a case study on the response of the grassland in the Hulun Buir Steppe of Northeast China to global warming in the past 20 years is made in this paper. It is found that, (1) The temperature in the Hulun Buir Steppe has increased remarkably than that in the global during the last 18 years; (2) The 4 selected areas averaged NDVI in growing season (from April to October) has obviously increased by 2.2% in the past 18 years; (3) The obvious increase of NDVI happened around 1988, when the mean NDVI during 1988~1999 is 7.8% more than that during 1982~1987. (4) Response of the Hulun Buir Steppe to the globe warming is remarkable. The NDVI and the temperature, especially the temperature in spring, have sensitive positive correlativity.

The exploitation of resources and an increase in civil engineering projects in the Junggar Basin has caused major environmental disturbance to the fragile desert eco-system. It is a serious problem that attracts global attention on how to restore and reconstruct the stable natural eco-system. Understanding soil moisture content and lateral water movement in arid areas, at a shallow depth, is of practical importance. On the one hand, lateral flow can be expected to reduce the groundwater recharge rate. On the other hand, it may result in a strong variability of water resources over short distances, thus affecting the distribution and composition of the vegetal cover. The eolian soil moisture condition is the primary factor that affects desert plant-cover in the hinter land of Junggar Basin, especially in spring (from March to May). With neutron probe, through field calibration, the soil moisture changes in different terrain parts, which are the crest, slope, the foot of the natural and disturbed dunes and the interdune land were measured. The data shows that the spatial distribution of the soil moisture in spring is closely related to the sun radiation, the depth of snow in winter, landscape position, the depth of soil, plant cover condition (cover-degree, plant species), and human impact. The data also provides scientific information and instruction for restoring and reconstructing the eco-system that has been damaged by engineering disturbance.

The Tarim River Water Resources Reallocation Project is specified because of the inland geographical aridity situation. The objective of this project in short-term is to solve the problem of unbalanced allocation of ecological water and to keep ecological safety of the whole valley. Here are three basic problems on the water resource space-time allocation. The first is the allocation of water quantity in longitudinal and transverse direction. The second is the structure of water usage quota for each section of the river valley. The last is the process control of the quota. According to the principle that social development should be based on ecological safety, the disposal of the water quota in a region should be started with restricting ecological water and the method of discharging deduction should be adopted so that water usage in a region is based on rigid restrictions. Water quota is a system associating with the quantity control and structure control of the water usage. The process control of water quota should be based on the principal that the quota should be increased when incoming flow is abundant and decreased when short. To distribute water quota, period choice and year-inner apportionment are other essential and practical problems.

The NOAA/NASA Pathfinder AVHRR Land (PAL) product is one of important data products for studying global vegetation. It contains global NDVI time series derived from NOAA-AVHRR at 8-km and10-day resolutions for the past two decades. Many studies have used the PAL product to analyze the global vegetation dynamics and trends in the past two decades with an assumption that either PAL has no systematic temporal errors or the errors are much smaller than the signals of the global vegetation changes. However, this study finds the significant systematic temporal errors in PAL due to the orbital drifting of NOAA POES satellites that increases the global NDVI value with aging of a satellite. Another source of NDVI errors is the volcanic aerosols, which have large negative effects on global NDVI value in the product. The aerosols brought into atmosphere by June 1991 eruption of Mt. Pinatubo reduced the means of the annual global maximum NDVI by 0.03, 0.067, and 0.027, for 1991, 1992, 1993, respectively. The aerosols from the eruption of El Chichon in 1982 reduced the mean of global maximum NDVI 0.016 NDVI unit for 1982 and 0.022 for 1983. Those errors are larger than signals of global vegetation change due to the climate change. After removing the errors by a statistics-based algorithm, it is found the mean of the annual global maximum NDVI increases at the rate less than 0.005 NDVI units per year.

After analyzing the heat conditions in the years of serious reduction of cotton yield in the main cotton-growing areas of Xinjiang, it is found that the cold disasters, especially the delaying cold disasters, are the most serious meteorological disasters to the cotton production in Xinjiang.

The area of aeolian sand soil in Xinjiang is 3.7189×107 hm² and occupies 25% of the total land area. Traditionally, it is considered that aeolian sand soil has low yield of crops due to its poor retention power of soil moisture and soil fertility. However, the stems of cotton growing on aeolian sand soil are small and their fictile shape is easy to be controlled. Thus, a culture mode of "increasing stems and bolls, double-layer and double-stem" of cotton is developed by scientific irrigation and fertilizer spread as well as artificial control of fictile shape based on the growth laws of cotton and the properties of aeolian sand soil, and a lint yield of over 3,750 kg/hm² has been reaped in successive 3 years. Currently, the cotton culture in Xinjiang is rapidly developed, the proportion of cotton-culture areas occupies 40~60%, the cultivating areas of other crops are reduced, the ecosystems are simplified, and the natural enemies in cotton fields are reduced. Alfalfa belts of 8~10 m in width are planted in the zones affected by shelter forests, the occurrence of Therioaphis maculata (Buckton) in alfalfa belts is 10~15 days earlier than that of cotton aphids (Aphis gossypii Glover), and in the alfalfa belts the quantity of herioaphis maculata (Buckton), the natural enemies, is 13.65 times of that in cotton fields when the cotton aphids occur. To resect the alfalfa this moment makes the natural enemies in the alfalfa belts enter the cotton fields and eat cotton aphids, which has good effects for preventing and controlling cotton aphids.

To study the effects of regional topography on its climatic distributions in Akesu area, three kinds of topographic factors are analyzed. Combined with the use of historical climatic data, some features of topographic effects on local climatic distributions are discussed.

Leaf stomata play a very important roll in plant physiological activities and the interaction between plant and atmosphere. In one hand, plants get CO₂ for photosynthesis through stomata. In the other hand, stomata control the water losses causing by transpiration. So that, stomata is not only the key element controlling transpiration and latent heat flux, but also the key factor for photosynthesis. Evidences indicate that besides plant physiological traits, stomatal conductance is very sensitive to environmental elements such as photosynthesis active radiation (PAR), relative humility (RH), air temperature (Ta), leaf temperature (Tl), ambient CO₂ concentration etc.

The Terrestrial Nitrogen-fixing Blue-green Algae, which are possessed of both photosynthesis and nitrogen fixation, are the leading organisms in the adverse circumstances. With their typical cell structures and physiological abilities, they are strongly resistant to drought, infertility etc. The growth of Terrestrial Nitrogen-fixing Blue-green Algae can rich the soils in nitrogen and organic compounds, which are benefit to other microbes and plants. Terrestrial Nitrogen-fixing Blue-green Algae are widely distributed in Gurbantunggut Desert. It was estimated that about 40% of the surface of the desert are covered by the "Black Crust". "Black Crust" is mainly occupied by Terrestrial Nitrogen-fixing Blue-green Algae. It is Terrestrial Nitrogen-fixing Blue-green Algae that construct the mechanical crust with a little other algae and fungi through biological, chemical and physical actions. So Terrestrial Nitrogen-fixing Blue-green Algae play an important part in desert fixation. It was analyzed that there are three species of the blue-greens in the "Black Crust": Microcoleus vaginatus(Vauch)Gom.,Scytonema ocellatum Lynbye and Schizothrix mella Gardner. We had isolated Microcoleus vaginatus(Vauch)Gom. and Scytonema ocellatum Lynbye. Some tests had been made to prove the feasibility of the desert fixation of the Blue-greens. Under experiment conditions, the blue-greens grown on the surface of sand, covered the sand quickly after the inoculation, and formed a mechanical fixed surface layer (7 days for Microcoleus vaginatus, 15-21 days for Scytonema ocellatum).

There are 18 species of Tamarix spp. in China and 16 of them in Xinjiang. As a group of bushes which widespread in salty and sandy land in arid zone, Tamarix spp. had gotten more and more attention by ecologists because of their unique bio-ecological characteristics, ecological and social economy functions. Wide Distribution of Tamarix spp. affects ecological environment stabilization of arid zone in western China. The modern distribution and habitat of Tamarix spp. diversity in Xinjiang were studied in this paper. Result revealed that water (surface water and high groundwater ) is the critical environment factor which determines the modern distribution of Tamarix spp.. Depend on analyzing groundwater lever and salt content of soil(two environment factors), author divided the habitat of Tamarix spp. into six type groups (low salt type with high groundwater, middle salt type with high groundwater, high salt type with high groundwater, low salt type with low groundwater and middle salt type with low groundwater etc.) which consisting of ten habitat types. Habitat of Tamarix spp. in Xinjiang never exists in isolation, but associate with each other. The groundwater lever and salt content of soil varies with the lapse of time, then habitats transform from one type into another and species of Tamarix spp. in habitats transforms accordingly.

A successful effectiveness to prevent the oasis from the desertification had been obtained by means of the method to establish the man-made vegetation in the south fringe of Takelamagan Desert since the middle of 80’s last century. This paper generalizes the characteristics of Calligonum and summarizes the ways to establish it (seedling, cutting and sowing) and main technical points of every ways. In the meantime, it also clarifies the strategy to select the different ways.

Population genetic structure and genetic diversity were studied using RAPD in five samples of Petrosimonia sibirica in Fukang, XinJiang. The results showed that amplification of 14 random primers detected 76 of 77 loci were polymorphic. The mean proportion of ploymorphic loci (P) of P. sibirica was 98.7%. It showed the higher genetic diversity existed in the subpopulations of P. sibirica. Furthermore, the study discussed the Shannon information index (H_POP/H_SP =0.6933), Nei gene diversity index (H_S/H_T=0.6948) and gene differentiation index (G_ST=0.3052). The analysis presented that the ratio of molecular variation was over 30% among subpopulations and about 70% within subpopulations. Therefore the genetic differentiation had happened among subpopulations of P. sibirica. On the other hand, the gene flow of P. sibirica (N_m=1.138) was less than that of cosmopolite species (N_m=1.881), and much lower than that of of Caragana spp. populations over Maowusu sandy grassland (N_m=5.9529). Additionally, through the correlation analysis, the relationship between the genetic distance of P. sibirica and latitude, longitude and altitude was not significant. It showed the geographical difference was not one of the potential factors, which affected the genetic differentiation of P. sibirica. At the same time, the soluble salt in soil of the oasis desert transitional zone might play a role in maintaining the genetic diversity of P. sibirica. The paper indicated that the mean proportion of ploymorphic loci (P)and Nei gene diversity index (H) of P. sibirica had the remarkably negative relationship (p<0.05) with the total K and Cl- in soil respectively. Above analysis showed that although much of genetic variation existed within the subpopulations, the genetic differentiation occurred among subpopulations. The natural selection may have a determinate effect on keeping the genetic variation and differentiation of the subpopulations of P. sibirica.

Random amplified polymorphic DNA (RAPD) markers were used to assess levels and patterns of genetic diversity in H. ammodendron (Chenopodiaceae). A total of 117 plants from 6 subpopulations on oasis-desert ecotone was analyzed by 16 arbitrarily chosen primers resulting in highly reproducible RAPD bands. The analysis of molecular variance (AMOVA) with distances among individuals showed that most of the variation (74%) occurred among individuals within subpopulations, which is expected for a crossing organism, and 26% of variation among subpopulations. Estimates of Shannon index and Nei’s index from allele frequencies corroborated AMOVA partitioning in H. ammodendron. UPGMA cluster analyses, based on genetic distance, do not revealed grouping of some geographically proximate populations. This is the first report of the partitioning of genetic variability within and between subpopulations of H. ammodendron and provides important baseline data for optimizing sampling strategies and for conserving the genetic resources of this species. The Percentage of polymorphic loci was as high as 96%, presumably being response to oasis-desert ecotone. There were gene flows (Nm=5.38 individuals/generation), based on gene differentiation coefficient (G_ST was 0.1567) between subpopulations, and strong habitat selection override the gene flow to maintain the subpopulation differentiation. Correlation analyses showed that there was significant relationship between genetic diversity and soil CL ion.

Hexi Aisle located in west of Gansu province is the base of national trade-corn. Recent years, because of the increase of population, the improving of economy and the damage of environment, many ecological problems appear more serious, such as desertification, shortage of water and degeneration of vegetation. So, in order to protect and improve the ecosystem and avoid advanced damage, it’s necessary to analyze the change of the eco-environment during the past ten years. Remote sensing is good at observation on long-term and insignificant change in environment. In the paper we used two periods TM image combined band 2,3,4. Then, through manual explaining under the GIS software, we got the environment vector data and built graphics database and attribute database. Those data primely present the eco-environment change of the past 10 years. With GIS method, overlay the two periods eco-environment vector map to taking the detail of the dynamic data of the eco-environment change (Guan Weihe, 1992). Regional eco-environment change is important part of the globe change analyze, many research indicate that regional eco-environment is driven by the natural and human activities. In our research, we find that many eco-environment changes are influenced by the alteration of the climate and human activities. Integrating social, economic and climate factors, we think that natural factors including temperature, water, salt, eroding and human activities including unreasonable agricultural practices, heavy livestock grazing and firewood cutting is the dominant driving factors in the change of the eco-environment. Especially, in the change and distribution of the eco-environment, human activities make a more important role. In addition, during the past 14 years, three major drainage area are suffering notable eco-environment including degeneration of vegetation, river water shortage, river breaking and lake shrinking. Accompanying the increase of population, excessive digging, heavy livestock grazing, strong eroding and desertification became more and more serious and rapid. Because of the weak eco-environment and special geographic location, research region is more important area to the regional and globe change analyze. The analyze in the region is very significant to the monitor of the eco-environment change, improving the weak eco-environment and avoiding natural disaster, especially reducing desertification and avoiding dust storm.

Ningxia Hui Autonomous Region locates in north west of China. Recent 10 years, the economic and social level of Ningxia improved much. Therefore, land cover influenced by the natural and human activities changed greatly. Remote sensing united GIS is an effective method to observing and overseeing the long-term and insignificant change of the environment or the ecosystem. TM images are the essential information sources of land-cover. In semi-arid and arid, especially in the transition belt of the physical geography, the method would be more useful to discover the change mechanism of land-cover. During the 10 years, farmland had great change, and about 86% was compensated by grassland. Rapidly increased population is the most important driver in the land cover change. So construction area also increased quickly. Comparing land cover change with socioeconomic variables, we found that the land cover changes with the little human influence were impacted by the climate alternation. Also climate alternation is another important driver. Among main land cover types, the changes are consistent with the climate change.

The study area of this paper is Dingxi County, a typical loess gully-hilly region of the semi-arid regions. The land use maps in 1990 and 2000 were compiled from the Landsat TM images and other data resources. There are 9 kinds of land use types. The slope data derived of contour lines. Referring to some metrics of the landscape ecology, 10 metrics were selected or developed for quantifying the land use characteristic, monitoring the land use changes and analyzing the relationships between land use, land use changes and the topographical condition, governmental policies of the Dingxi County. Some conclusions were obtained. The selected metrics can quantify the land use and land use change in typical loess gully-hilly region, Dingxi County. The land use and land use change have good spatial distribution regularities in the slope grades. The governmental policies are the primary driving factors for the land use changes in our study area. The policies are reclaiming the slope farmlands and grassland into terraces, rainfall-collection works, and reforesting and regressing some sloping cultivated lands.

An accurate land cover mapping is a prerequisite to run all biospheric models. In this paper, NDVI (Normalized Difference Vegetation Index) and NDWI (Normalized Difference Water Index) time-series of data sets derived from 1-km SPOT/VEGETATION products were used to compile the land cover map of northwest China. The unsupervised classification technique of ISODATA was applied to classify the land cover classification system. With the assumption of the 1:100000 land use map of northwest China interpreted from TM images as the truth, the accuracy of the SPOT/VEGETATION land cover map was evaluated by validating 47 sampling units randomly selected in the whole mapping region. Each sample is a square unit of 25km´25km. The validation results showed an approving accuracy of the land cover map of northwest China. In addition, the combination of NDVI and NDWI vegetation indexes is an effective method on large regional land cover mapping. Meanwhile, three major problems are addressed for explaining the reasons that influence the accuracy of land cover mapping in this region

Evaluating status and possibility of desertification is an important field in arid and semi-arid zone. For Gansu province is located in inner northwestern China, fragile environment and irrational human activity have made it a relatively serious area of desertification in northern China, and a main source of dust storm happening in China every year as well as. The paper acquires data of variety of land use and desertification on Gansu province from 1986 to 2000, by interpreting TM images of the two periods with GIS software ARC/INFO. Then, on the basis of the data, the study uses index of desertification extent to analyze spatial pattern of desertification on the province. The result indicates that on desertification scale, the Hexi corridor exceeds the other areas, in contrast to it that desertification extent of the Hexi corridor is less than it of the other areas. Based on the above results, with support of integration of ARC/INFO, statistic software SPSS and office software EXCEL, the study uses means of principal component analysis (PCA) to evaluate potential extent of every county on possibility of desertification. The result shows that the possibility of desertification of the Hexi corridor and the Gannan region exceed it of other areas, which is in accord with present spatial pattern of desertification scale on Gansu province.

The objective of this study was to explore satellite-based vegetation phenology to characterize ecosystem variability in the northern China steppes. Advanced Very High Resolution Radiometer (AVHRR) maximum Normalized Difference Vegetation Index (NDVI) composite data set from 1982 to 1990 was used to detect the onset of vegetation green-up for the steppe ecosystems. Our findings show a strong linkage between onset of green-up and climatic factors in the region. An Ecosystem Variability Index (EVI) was derived using the coefficient of variation for date of onset of green-up. The EVI showed the meadow steppe/forest ecosystems to be least ecologically variable and the desert steppe to be most variable. Large areas of typical steppe, near the desert steppe ecotone, exhibited similar EVI values to those of the desert steppe, suggesting greater ecosystem variability in this typical steppe area. This suggests that large expanses of typical steppe in this region are undergoing ecosystem changes that could result in lower grassland productivity and eventual changes in land use practices.

Based on some remote sensing data and software platform of image processing and analysis, the standard image for ecological thematic mapping is decided. Moreover, the vegetation type maps and land sandy desertification type maps are made. Relaying on differences of natural resources and ecological environment in Tarim River Basin, the assessment indicator system and ecological fragility index (EFI) of ecological environment are built up. The assessment results are very severely. That is, EFI is only 0.08 in Akesu River Basin, it belongs to slight fragility area. EFI of Yarkant River Basin and upper reaches of Tarim River Basin are 0.23 and 0.25 respectively, both of them belong to general fragility areas. Meanwhile, EFI of Hotan River Basin and middle reaches of Tarim River Basin are 0.32 and 0.49 respectively; they all belong to middle fragility areas. However, the fragility of the lower reaches of Tarim River Basin belongs to severe fragility area that the EFI is 0.87.The maladjustment among water with hot and land as well as salt are hindrance of energy transfer and material circulation and information transmission. It is also the main reason that caused ecological environment fragility.

In arid and semi-arid area of North China, one serious problem is soil degradation and expanding desertification, and annual net primary productivity (NPP) of terrestrial ecosystem is low, and the converted soil organic matter is also very small. Moreover, for short of precipitation, it is mainly the aeolian erosion of soil that causes severe loss of soil organic matter, which plays a negative role on NPP. According to the field data of second national soil profile survey, this paper computed the soil organic matter pool of surface soil, and its result indicates that desert has small pool of soil organic matter and grass land has big pool of soil organic matter. Further, based on remote sensing investigation of soil erosion, this paper computed annual soil loss and its distribution map, and estimated the soil organic matter lost for aeolian erosion. And NPP was also calculated by using light energy efficiency model. So based on pool of soil organic matter, loss of soil organic matter and NPP, this paper analyzed the balance of soil organic matter in North China, and we found that the overall situation of soil organic matter is loss in aeolian erosion area.

A large-scale economic development program in western China has begun since 1999. Fast urbanization is expected with urban population increasing dramatically. Western China is mostly in arid and semi-arid climate zone and water resources are very limited. It suggests that an early warning system specifically designed to deal with urban droughts should be developed. Thresholds on identifying the water related hotspots must be determined based on different regions and economic sectors.

Soil moisture, salinity, ground water table and salt concentration were measured monthly in seven typical plant communities for one year in Sangonghe basin of Xinjiang. Temporal dynamics of soil water and salinity during growing season were compared within these communities. The dominant species in each of these communities were Suaeda physophora, Reaumuria soongorica, Anabasis aphylla and Kalidium foliatum, Tamarix ramosissima, Alhagi pseudalhagi and Haloxylon ammodendron respectively. Results show that soil water content and salinity were significantly different among all these communities. In the edge of alluvial fan and low reaches of the river, ground water table was high, soil profile was moist, and salt concentrated in the soil upper layers and surface. Soils were all saline with dominant species of T. ramosissima, A. aphylla and K. foliatum. In the plain area, communities were dominated by R. soongoricaand S. physophora Ground water table was generally low, but soil surface and up layer contained high salt concentration. Soil here belonged to strong to medium salinized soil. In ecotone, ground water table increased due to the irrigation in the nearby oasis. From soil surface to deep layers, water content increased gradually with no salt accumulation for all the layers. Vegetation in ecotone was stable and dominated by A. pseudalhagi. In intervale of desert, ground water table was very deep and soil was very dry throughout of the profile. There were no significant differences in vertical and temporal change of soil moisture. Communities were dominated by H. ammodendron. Spatial and temporal dynamics of the soil moisture and salinity caused community subrogation, and were the two main factors that affected distribution and succession of plant communities.

Based on snow, rainfall and harvest archives records in the Qing Dynasty (1644-1911AD), the modern meteorological observation data, the annual winter mean temperature and seasonal precipitation series from 1736 to 2000 and the series of harvest in summer and autumn from 1730 to 1910 are reconstructed. Meanwhile, the characteristics of climate change and the relationship between climate change and harvest are analyzed by using the high-resolution data. The result shows: (1) Warm and cold changes in Xi'an have obvious inter-centennial fluctuation. Climate is relative warm in the 18th century and cold in the 19th century, but in the 20th century, climate turn to warm period with a rapid warming trend. (2) Precipitation changes have obvious inter-decadal fluctuation. It goes through six rainy periods and seven drought periods in Xi'an since 1736, in which the mean precipitation in the rainy periods is 16% more than that in droughty periods. (3) The coefficients between the precipitation from June to August and the harvest in autumn, and the precipitation during the period of September to May and the harvest in summer are remarkable. The relationship between inter-decadal temperature variations and harvests is significant too, which suggests that the long-term warm /cold change has important effects on harvest.

Driven by anxiety of population growth and decline of living standard of human beings, Research on environment in arid zone has been received significant attention in recent years. The flourishing landscape ecology provides a suitable way to study on environment. Meanwhile, the application of RS techniques brings essential data for landscape study. Integration both of them promotes study on environment. Among them, as key substances, the landscape pattern analysis is one of good methods to discuss regional environment. Although a number of papers about it have been published, little practical work has been done for arid zone in China. For these reasons, it is very important and urgent to understand the landscape pattern characteristics and environment trends in arid zone in China, especially in continental river basin in west of China. Supported by the modern techniques of RS, GIS and GPS and CBERS-1 data and aerial photograph, using the methods of landscape pattern analysis, the paper analyzed the landscape pattern characteristics and environment trends in the middle reaches of Hetian River. The main conclusions has been given as follows: (1) On macroscale, there have two kinds of typical deserted landscape patterns in arid zone: in the north of region, dominated by river corridor, the landscape is symmetrically distributed with waters and wetland-forestry and grass based on desert matrix; in the south of the region, indicated central line by river, linked by sub-rivers and irrigation canal network, the landscape shows artificial oasis with primary cultivated lands on desert matrix. (2) Compared landscape pattern figures of 1959 with the one of 2000 and measured values of landscape patterns, fragmentation of each landscape types becomes low and connectivity is good. Landscapes controlled by human are increasing shapely, such as artificial rivers, irrigation canals, reservoirs, residences, cropland and so natural landscapes are been greatly reduced, especial in desert and Gobi area. (3) The landscape trends of landscape pattern are equalizing, distribution by human is enhancing, landscape structure is rationalizing, and the regional quality of environment is optimized. While, the whole region is still under a vulnerable ecological environment.

Photosynthesis and transpiration are the most important physiological activities for plants. They are closely related not only to photosynthesis active radiation (PAR), air temperature (Ta), relative humility (RH) and ambient CO₂ concentration, but also to plant stomatal conductance and intercellular CO₂ concentration. Their relationship can be analyzed through statistic methods to indicate plant eco-physiological ability bearing to environment. By means of measuring the photosynthesis of Haloxylon ammodendron and Reaumuria soongorica in the Sangonghe River valley we have dealt with similarities and differences of two species. Results show that net photosynthesis rate of Reaumuria soongorica is slight higher than Haloxylon ammodendron, but water use efficiency of Haloxylon ammodendron is evidently higher than Reaumuria soongorica. It suggests that Haloxylon ammodendron has strong bearing ability to drought in natural habitat.

The canopy spectra of rice under different nitrogen levels were studied. Some red edge parameters in the first derivative reflectance curve (wavelength, amplitude and area of the red edge peak) were used to evaluate rice leaf chlorophyll, LAI. Red edge positions move to longer wave bands till booting stage and move to short bands after booting stage. A high correlation was found between chlorophyll content of top leaves and the wavelength of the red edge position and between LAI and the red edge parameter. Then, the red edge was found valuable for assessment of rice above stand leaves chlorophyll contents. But a correlation was not found between chlorophyll b content of leaves or carotenoid or albumen-nitrogen or non-albumen-nitrogen and the wavelength of the red parameters. Some red edge parameters are one of the best remote sensing descriptors.

The forming of the abnormity and roughness on the boundary of desert is related to the interlace between the environmental factors and jamming, and it reveals a kind of fixity of statistic self-similarity. The distribution structure of the community patchiness is related to site environmental and ecologic conditions. The ecologic strategies of the four types of population distribution in Fukang, which is between random distribution and mass distribution, show clearly that distribution is determined mainly by the adapting to the physical environmental factors. Every population shows all kinds of self-similarity phenomenon and order in life history dynamic, which indicates different ecological characters and forms kinds of modules of physical and biological environment. The statistic self-similarity of this module in shape and structure is formed by the erode of desert and jamming, whose form is revealed by the geometry structure of the symmetry existed between the size used in the measure, namely the hackle-protruding coarse islands formed on the plane of block is knotted with smaller islands, in which there is similarity in geometry structure among any relatively independent patchiness. The irregularity degree at the verge of patchiness can be showed by fraction dimension, but what is revealed is the obstinately growing character, which is paid out by the vegetation in the stitched blocks in order that it can adapt environment.

Through "3S" techniques, the study has analyzed the quantitative, qualitative and spatial changes of the Keriya oasis land cover from 1989 to 1999. In contrast to the data of the past years’ fieldwork, the environmental change and the desertification degree of this study area for nearly 10 years have been analyzed, and the precaution line on the environmental evolution of the oasis has been extracted.

The optical property and bio-chemical composition of yellow substance in Jiaozhou Bay had been measured in a laboratory where the distribution of absorption coefficients of yellow substance in Jiaozhou Bay and near Qingdao City, that of fluorescence properties as well as that of the bio-chemical components contained in the water samples of yellow substance had obtained. From the data analysis, it is found that the absorption coefficient of yellow substance has a better linear relationship with salinity of the seawater, and is a better indicator for showing the environmental pollutants, water quality and the micro-construction of current field. These results will provide the reference for further searching the localization of satellite algorithms of yellow substance in China waters, monitoring environmental quality and applying to oceanographic research in the future.

The effect of depth to ground water on water relations of obligate phreatophyte Populus euphratica (Salicaceae) was investigated in the foreland of the hyper-arid Takelamakan Desert in Xinjiang, NW China. P. euphratica grow on sand dunes of different height (0--15.4m) above ground water that was the only water source for the species. The depth to ground water from the surface of the lowest sand dune was 6.8m under Populus. The water relation data illustrated the negative impact of sand dune height on water status of the species. Predawn and midday water potentials decreased significantly with increasing sand dune height. Water relation data suggest that decreases in hydraulic conductance with increasing distance to ground water have caused decreases in stomatal conductance due to a diminished water supply in plants on higher sand dunes. Results of this study indicate that whole-tree hydraulic conductance for Populus is heavily influenced by below ground hydraulic conductance. Whether the variations in hydraulic conductance are a function of increased path length or if they are the result of morphological changes in the conducting tissues remains further investigation. A detailed knowledge of hydraulic parameters in the root system is required to assess the effects of hydraulic limitations on plant water relations.

On field sites, water physiological characteristics of the desert legume Calligonum were investigated during the vegetation period in 1999(2000) in the southern fringe of the Takelamakan Desert, Xinjiang, NW China. The seasonal variation of predawn water potentials and of diurnal water potential indicated that Calligonum plants were well water supplied and it has stronger ability to maintain the water balance within the body over the entire vegetation period. Water relationship parameters from pressure-volume analysis confirmed that Calligonum plants were not drought stressed and xylem sap flow measurements further indicated that Calligonum plants were well water supplied during the summer months. The data indicate that artificial flooding only had limited effects on the water relations of plant. Long-term adjustment to the hyper-arid environment and its growth (survival) of Calligonum maybe is dependent on permanent contact with ground water. Therefore, it is important that variations of ground water depth are kept to a minimum. The study will provide theoretical basis for the restoration and management of natural vegetation in arid and semi-arid regions.

Genetic structure and differentiation of Reaumuria soongorica population from the desert of Fukang, Xinjiang were assessed by the means of random amplified polymorphic DNA(RAPD) markers. The results show that the higher genetic diversity and the genetic differentiation exist in the population of Reaumuria soongorica, which is composed of 7 subpopulations and 136 individuals, generated by 15 primers. 71 loci have been detected and 69 were polymorphic. The mean proportion of polymorphic loci (PPB) was 97.18%. The analysis of Shannon phenotypic diversity index (0.3075), Nei's gene diversity index (0.3127) and G_ST (0.3120) indicates that there were more genetic variations within the subpopulations than those among the subpopulations. The gene flow among the subpopulations of Reaumuria soongorica (Nm=1.1028, Nm>1) was much less than that of the common anemophytes (Nm=5.24), so genetic differentiation occurred to some extent. The results of AMOVA analysis show that 61.58% of the genetic variations exist among the subpopulations, and 38.02% within subpopulations. Additionally, through the use of clustering analysis, principal factor analysis and the correlation analysis, we found that the genetic structure of natural population of Reaumuria soongorica was related to some ecological factors (soil factors mainly) of the oasis-desert transition zone. The genetic diversity level of Reaumuria soongorica had the negative correlation with the content of soil total P and Cl- significantly (P<0.05), on the contrary, it had the positive correlation with CO₃^2- significantly (P<0.05), showing that the distribution of the individuals of Reaumuria soongorica in sampling sites correlates with certain soluble salt, Furthermore, the genetic diversity of the natural population of Reaumuria soongorica increased with the decreasing of the content of organic matter, water, total N and total P in soil. This suggests that there are some relations with more potentiality of the genetic variation of Reaumuria soongorica in its long-term evolution to adapt worse environment.

The relationship between species diversity of plant communities with soil factors was discussed with two statistical methods: single variable regression and multivariate stepwise regression. Both single factor and multiple stepwise regression analysis indicated that, soil pH, total salt and soil moisture played significant roles to species diversity by single-factor regression, could be all the same under interactions of multiple variables. However, organic substance played striking role by single-factor analysis, was removed under interactions of multiple factors. Of the three layers (0-10cm of surface layer, 10-30 cm of middle layer and 30-50 cm of deep layer), the middle layer strikingly influenced species diversity of plant community. Therefore, the conclusions by the two analysis methods were basically consistent with each other.

Genetic diversity was studied by RAPD analysis in 7 subpopulations and 136 individuals of Reaumuria soongorica in the oasis-desert transitional zone of Fukang, Xinjiang, China. The experiment involved the different microenvironment stresses (ecological factors) in the oasis-desert zone of Fukang: (1) geographical location, including latitude and longitude; (2) the components of the soil, such as the content organic matter, N, P, K, water, salinity and pH value. Comparisons were based on 71 loci amplified by 15 oligonucleotide primers. These DNA polymorphisms appeared to be associated with the microenvironment stresses. The results indicated that the significant correlation existed among the ecological factors in the different microenvironments. And the allele frequencies of 39 from 71 loci highly related with the corresponding microenvironment factors. The mean proportion of polymorphic loci (P), Shannon information index (I), Nei’s gene diversity (H), observed number of alleles (Na) and effective number of alleles (Ne) of R. soongorica seven subpopulations related each other to some extent. The paper showed that the microenvironment stresses (ecological factors) played the important role in adaptive genetic differentiation of R. soongorica population, which resulted from the natural selection, and not by chance from subpopulation subdivisions.

NDVI(Normalized Difference Vegetation Index) values range from -1.0 to +1.0, areas with NDVI < 0 rarely contain any vegetation, while NDVI >0.6, vegetation cover reaches 100%. The FVC (Fractional Vegetation Cover) values range from 0 to +1.0. Above this threshold the fractional vegetation cover increases approximately as the square of the NDVI, and reaches 100% at an upper NDVI threshold, which is considerably less than 1.0. In arid and semi-arid regions, FVC is superior to NDVI. In this article we got the classification rules by using the resolution 1km FVC combining with DEM (Digital Elevation Model) to classify the vegetation types in arid parts of western China. This classification system was used to classify all FVC images of the resolution 8km*8km from 1982a to 2000a, in this way, we got the classification maps of vegetation for every year. From these classification maps we calculated three majority maps from 1982-1989a, 1990-1995a and 1996-2000a. Supported by software ARC/INFO allowed us to decided wheter cells were degraded or improved after comparing every cell value at same location in three serial maps and then getting the evolution map of vegetation. The main results are as follows: 1) the vegetation in all of arid west China has increased; 2) the vegetation was increased and the rate is higher than in all study area; cells showing improvement in mountainous areas are almost equal to cells showing degradation3) there were two types of improvement patches; the oasis patch increases around old oases and the plain sparse desert patch has also increased; 4) degradation patches appear more frequently in the lower reaches of the Tarim River, in all reaches of Cherchen River, the Jungger basin and to the south of Alxa Right County of Inner Mongolia; 5) in mountainous areas, most of the improvement cells took place in the south of the Tianshan mountains and Pamir high plain, degradation cells are located on the slope of the north Kunlun mountains as a long narrow region and big patch assembled in the Aljin Mountains and the north slope of the Qilian Mountains.

Based on aerial images the GIS technique supported by ARC/INFO software was used to analyze the oasis-desert landscape heterogeneity and its dynamics of Fukang transect with spatial scale change, using landscape structural indices to reveal and compare the structural characteristics of oasis-desert landscape heterogeneity, which was useful to study the dynamics process of landscape heterogeneity through time from different aspect in arid area, which was useful to study the dynamics process of landscape heterogeneity. The results show that oasis-desert landscape in studied area was controlled by the combination of environment heterogeneity, human dimension and activities, and natural vegetation succession. The mutation, contrast and heterogeneity of ecological interface between oasis and desert ecosystem increased. Rare natural or non-regional mosaic of patch show obvious sensitivity to spatial scale, the change ratios of theirs area and perimeter are greater than large patch. With the disturbance of moderate scale more small patchiness combines into more large patchiness. But more patchiness of mosaic will vanish with violent disturbances or isolations of scales. At the same time it has proved that the analysis of landscape heterogeneity is quite effective research means in ecology to measure and quantify the relationship, interaction and response between the structure and function, patterns and processes of oasis-desert ecosystem.

This article discusses the relationship between desert ecosystem structures, succession and environment factors which include soil moisture, salt content and pH values in Fukang of Xinjiang. Some preliminary conclusions have been drawn as following: (1) In the study area the niche breadth of typical species in desert vegetation/ecosystem is closely related to environment factors, such as soil moisture, soil pH and salinity. The biggest niche breadth species are Haloxylon ammodendron (1.412) and Reaumuria soongorrica (1.399), which are dominant species in climax communities of the region, and they have very strong adaptability to the arid desert environment. The niche breadths of Nitraria rovorowskii, Kalidium foliatum and Suaeda acuminata range from 0.8 to 1.2. The smallest niche breadth species are Tamarix spp. and Anabasis spp., ranging from 0.4 to 0.8, and both of them show sensitivity to drought and salinity. (2) Low species diversity in desert vegetation/ecosystem of Fukang was found. In general, the grade of community diversity from high to low is defined as: Tamarix soongorica community, Kalidium foliatum community, Suaeda physophora community, Halocnemum strobilaceum community, Haloxylon ammodendron community, Salsola passerina community, Reaumuria soongorica community, Bassia spp. community and Suaeda acuminate community. The most important factors that influence the species diversity of communities are soil salinity and pH values. Because of saline-sodic environment desert vegetation has developed a saline-sodic endurance ecological type. The main effects of salinity on vegetation are observed in the change of dominant and constructive species in communities, and halophyte becomes the dominant species gradually. (3) The limit factor on secondary succession in regional ecosystem is soil salinization. The trend and phase of community succession are in accordance with soil salinization development. There are three soil types: non-salinity, saline soil, and strong saline soil. Communities of Bassia spp., Suaeda acuminnata, Petrosimonia sibirica, Suaeda physophora, Anabasis spp., Kalidium foliatum, Haloxylon ammodendron. Haloxylon ammodendron distributed in non-saline soil and Reaumuria soongorica community is regarded as a climax community in this area and distributed in all kinds of saline soils. The appearance of Tamarix spp. is the result of succession development responding to salinity and increased water content. The plant communities are distributed, in turn, within the entire basin because groundwater table and soil salinity changes from the foothill of mountain to desert, and this sequence is the same as the secondary succession serial of the vegetation / ecosystem of this area.

Fractional vegetation cover data (FVC) based on the annual maximum NOAA/AVHRR NDVI (Advanced Very High Resolution Radiometer normalized difference vegetation index) data and the ground meteorological data have been used to analyze the relationship between the temporal and spatial evolution of ecological landscape pattern and climate change in Xinjiang autonomous region, China from 1982 to 1993. It is found that during this period, the averaged oasis cropland or low-damp forest-shrub meadow occupies 7.50% of the whole region, desert dune/barren desert 25.70%; temperate semi-arbor desert 21.70%; temperate shrub and semi-shrub desert 8.36%; alpine subalpine desert steppe 7.71%; temperature gramineous and ruderal steppe 7.63%; mountain forest steppe 2.13%; high-cold barren 8.93%; high-cold low semi-shrub desert 9.08%; water/ice 1.26%. Compared with the 30-year (1961-1990) climatology, the 12-year averaged annual surface air temperature and precipitation does not incur over the mountain region; instead it occurs over the region with a concentrated distribution of oases, suggesting the positive role of oases in adjusting regional climate. The area of temporal steppe also increases with the increase of precipitation and temperature. Together, these results demonstrate that, during the 12-year period, the condition of vegetation cover has been improved and large-scale desertification does not occur in Xinjiang.

Landsat Thermal Mapper data were used to monitoring the vegetation cover change in east part of the Hunshandake sandy land. The NDVI in middle September are 0.47, 0.67, 0.65 and 0.33 in 1987, 1996, 1998 and 2001, respectively, which highly correlated with the rainfall of July and August. There are some regions showed vegetation degradation which could not recover in a short time, most of them located in poor vegetated areas. And the degraded area is increasing from 1996 (3.8%) and to 1998 (6.0%). The vegetation condition shows improvement in 2001, and this may associated with the effort made by Chinese government to improve the environment of Hunshandake sandy land.

In order to have an objective understanding of the status that vegetation is resumed and the progress that the ecology environment construction project makes in Shaanxi province, we utilized the year of 1997 as a benchmark in our investigation and did the dynamic supervising for the variations in the north part of Shaanxi province under the support of 3S technology. The major task of the dynamic supervising had been completed by the software of ERDAS IMAGINE. Three dynamic supervising methods are used: (1) Difference value or ratio value of TM images from two different periods was calculated and the area of variation was obtained. (2) TM remote sensing images from the two different periods are merged, based on which the corresponding relationship between the zone where the light spectrum property changed abruptly and the variation of practical use of land was found. (3) Light spectrum curves for different ground objects in different areas were established on the basis of the classified result of 1997. According to those curves, the present classified diagram was made and the variation diagrams of the land using were obtained after comparing these two classified diagrams.

The hill and ravine area on the Loess Plateau is the typical region of serious soil erosion, excess reclamation, and deteriorated eco-environment in middle reaches of Yellow River. The main project of eco-environment construction is that recover vegetation, and quit high sloping cultivated land to forest or meadow. The local government in the concerned region poses that sloping cultivated land higher than 15 degree should quit. How many are there qualified and how about their distribution? These are the basis problems of the execution of the eco-environment construction project. In this paper, using TM image and digital relief map, the interpretation of land use classification and the calculation of slope are made for Baota , Yan’an, with the software of ARC/INFO and ERDAS IMAGINE. And also the sloping cultivated land is mapped, basing on the composite analysis of land use map and slope map.

Now, the recovering and reconstruction of ecology environment are more and more focused by people all the nation, when government began to develop the west of nation. But, how to make the exact evaluation to the construction work of ecology environment, and how to make the best out of the limited resource of constructing work, these need to dynamic monitor the variation of the land-use in research region. In this paper, we mainly work over the method witch using remote sensing technology and working with LANDSAT TM satellite RS images, digital evolution model data, RS base situation investigation data, vectorized data of terrain map and outside investigation information etc., to establish the models based on judgment rules, acquired from expert experiment, and form the expert classification system. The research results indicate that (1) it is precise method to classify the RS images because of combined use of all kinds of data and science geographic model, especially, the variation of land-use can be cleanly interpreted from RS images. (2) It can be used to classify the same objects with same spectral feature which can not be classified by traditional methods just like supervised and unsupervised classification. (3) By using this method, the precise of classification can be improved because it excludes something being classified unreasonable.

Taking 125th regiment of the 7th Agricultural Shi as example in Xinjiang, an evaluation model of soil fertility was established by using GIS and mathematical method. Chart of soil fertility information was build in 125 regiments, based on these, established a cotton fertilization recommendation support decision system, the system can realize fertilization recommendation, fertilization consultation and prescription, making GIS chart, soil fertility resource analysis. The results as follow: The soil fertility in this area was mainly middle level, and the ratio of soil area with high, middle and low fertility amount to 30.5%, 41.5% and 28.0% respectively. Main reasons that affect the full utilization of soil fertility were soil fertility input.

In this paper, the boundaries of the farming-pastoral belt for 10 stages for the last 2000 years are constructed by using the historical records of land uses, population, production and tax styles in this region extracted from Chinese historical documents, and the shift of farming-pastoral belt was discussed. The results can be summarized as follows: (1) During the last 2000 years, the general trend of this belt shifting was northwestwards, which expresses the effects of human dimensions. The pressure of population growth, development of economics, blending of cultures and development of technology had shown their effects on every epoch. (2) The most north ¨C western extension of the farming-pastoral belt occurred in periods from the mid-2nd century BC to the early 1st century AD (early Western Han Dynasty to early Eastern Han Dynasty), the late 6th century AD to the early 9th century AD (Sui Dynasties to mid-Tang Dynasty) and the mid-10th century to the mid-14th century AD (the period of Song and Yuan Dynasty). They are just coincident with the epoch of warm climate with a relative humidness. When the climate ran to a cold epoch, accompanied by a relative dryness, the belt shifted southeastwards.

The deterioration of ecological environment in arid areas has restricted economic development and the improvement of people's living standards. Therefore it is necessary to implement the construction of ecological environment in sustainable development of economy. This paper consists of three parts. The first part introduces the present status of western ecological environment. The second part analyses issues of information unsymmetry. First, it explains meanings of game theory and other concepts concerned. Then it analyses the reasons that game behaviors emerge. Last it analyses game behaviors caused by information unsymmetry between central government and local governments and between central government and individuals in the construction of ecological environment. Advice and measures are put forward in the last part.

A major monitoring area, a part of the middle reaches of Heihe basin, was selected. The Landsat TM data in summer of 1990 and 2000 were used with interpretation on the computer screen, classification and setting up environmental investigation database (1:100000) combined with DEM, land cover/land use, land type data and etc., according to the environmental classification system. Then towards to the main problems of environment, the spatial statistical analysis and dynamic comparisons were carried out using the database. The dynamic monitoring results of 1999 and 2000 show that the changing percentage with the area of 6 ground objects are as follows: land use and agriculture land use increased by 34.17% and 19.47% respectively, wet land and water-body also increased by 6.29% and 8.03% respectively; unused land increased by 1.73% and the biggest change is natural/semi-natural vegetation area, decreased by 42.78%, the main results above meat with the requirements of precise and practical conditions by the precise exam and spot check. With the combinations of using TM remote sensing data and rich un-remote sensing data, the investigations of ecology and environment and the dynamic monitoring would be carried out efficiently in the arid area. It is a dangerous signal of large area desertification if the area of natural/semi-natural vegetation is reduced continuously and obviously.

This paper analyses grassland dynamics in china from 1995 to 2000 under different aridity based on RS and GIS to discover the rule in it. The results show that the amount of grassland is reduced to 5.49 x10⁴hm². There is heavy grassland degradation in arid region, especially at low cover grass. The mainly change is becoming farmland and grassland and grass resource having different degree degeneration. The driving force of grassland dynamic is mainly natural and human activities. The main reason of grassland changing into farmland is population pressure; grassland degradation is caused by over graze etc. Because grassland lies in west and north of china, its area reduction and grass cover decrease will lead to china north environment worsen. Moreover the grassland decrease will restrict region economy development.

Microclimate observation at 2 heights (10 and 50 centimeters) in young cotton plants fields with both normal windbreak and non-normal windbreak were carried out when a dust storm took place in May 1998. Meteorological indices on the intensity of damage to the young cotton plants were obtained. These results were shown that 5% young cotton plants were damaged slightly when average velocities at the 2 heights were 1.5m/s, 2.6m/s respectively; 10% young cotton plants were damaged when these velocities were 1.6m/s, 2.9m/s respectively; 20% young cotton plants were damaged when these velocities were 1.8m/s, 2.9m/s respectively; 35% young cotton plants were damaged seriously when these velocities were 2.3m/s, 3.4m/s respectively. Economical evaluation on these plants’ damages caused by the dust storm was also conducted. The above indices were tested to be suitable in Hetian region. It is suggested that normal windbreak should be built in Hetian region in future.

Black soil shoal grassland is one of serious soil degradations in the Yellow River source regions. Large area mapping and monitoring of serious soil degradation is conducted typically using aerial sketch mapping and where necessary, ground survey. Both techniques have limited utility in wilderness areas where ground access is difficult and aerial mapping is too costly. Sub-pixel processing for analysis of Landsat Thematic Mapper (TM) imagery of Black soil shoal grassland was utilized and compared with survey. The study area was on Gande County, west part of Yellow River area in Qinghai province, west of China. Three dates of imagery were acquired and processed using Imagine Sub-pixel Classification software. The results were compared with existing limited ground survey data, and then three dates of result was compared. The sub-pixel analysis method can successfully detect Black soil shoal than using custom classification technology. Sub-pixel analysis can be an effective supplement to other means of soil degradation where the geographic extent of the degradation is too large for standard aerial sketch mapping techniques and dynamic surveying in cold and arid areas. The result also showed that the serious soil degradation extended very quickly, the velocity was about 3.4 percent every year.

Taking the watershed characteristics in arid area into consideration and using GIS for the means of getting, saving and processing spatial data, based on digital landform analysis, this paper puts forward a method to simulate the processes of water forming and flow concentration in any watershed grid dynamically. It provides a new way for runoff modeling, flood forecasting, environmental disaster prediction in middle-high mountain and no observation station watershed. It is demonstrated by a case study in the Urumqi river basin in Xinjiang, China.

The detailed land use/cover classification using remotely sensed data are the best means of delineating the surface changes for sandy desertification monitoring. The analysis of land use/cover with ancillary in GIS and in situ fieldwork shows that the land use/cover type can be used as indicators of sandy desertification severity effectively. Based on the analysis of the multi-temporal and multi-spectral Landsat TM data with ancillary data in GIS, sandy desertification of grassland was detected in 1987 and 1996. The results indicate that Gonghe Basin is one of the most desertified regions in the upper reach of the Yellow River, northeast Qinghai-Xizang Plateau. Among the sandy desertified lands, the severe and moderate sandy desertified lands are easy to expand, as well as to reverse. Therefore, these kinds of sandy desertified land will be the main conservancy areas in the future. It is necessary and urgent to combat desertification and protect environment in the upper reach of the Yellow River.

The keystones of research on modern volcanic hazards and calamity are from static research on local or regional change to dynamic research on global change, which emphasize particularly on monitoring volcanic activity and countermeasures of disaster recovery. Geological problems are emphases of volcano study in China in the past few years. Research on volcano mitigation starts now. There is still a few case of integrative risk assessment. Baitoushan volcano in the Changbaishan region is an active volcano with the most possible eruption and causing hazards in China. So the paper introduces a kind of brand-new Geographic method - Geographical Information System (GIS) and Remote Sensing (RS) to risk evaluation of volcanic hazards and attempt to introduce a kind of new risk evaluation approach of volcanic hazards based on Area Source Model. When choosing evaluative indexes, we take three aspects of fatalness of volcanic hazards, socio-economic vulnerability, harmfulness of causing-disaster factors into account.The fundamental data of evaluation in the studied area are acquired by the method of man-machine interpreting TM image and referring to forefathers' research results to do correction. Cell (1 km x 1 km size of raster unit) is partitioned in Changbaishan region, which is realized in raster GIS platform. The above risks were combined with the cll based on Area Source Model following mathematical models of risk evaluation on ARC/INFOR GRID sub modular. From risk evaluation result of volcanic hazards in Changbaishan region we can conclude that : 1. The value of risk is lower with far from Baitoushan crater, which is tallied with other scholars' and the general cognition. 2. The contribution to risk of pyroelastic flow is very big, while the influence of fulgurite is comparatively small, which is identical with the fact that the amount and harmfulness of pyroelastic is much larger than flugurite. The following fact shows that the method that the dissertation adopts is very practicable.