The regional disparity of development has always been one of the topics given higher priority in the fields of physical geography and economic geography. Even so, how to quantitatively assess the impacts of physio-geographical pattern (PGP) on the regional development disparity has been ignored for a long time. In this paper, taking the partial coefficients of determination calculated from marginal contribution rate equation as an index which indicated the marginal effects of physio-geographical pattern on the spatio-temporal differentiation, we adopted a quantitative method to assess the impacts mentioned above. The paper concretely enunciated the key scientific issues for the establishment of such method and the technical steps.Regarding the GDP, per capita GDP, primary industrial output value and secondary industrial output value were taken as the study objects, using the evaluation methods built by the researchers, we initially analyzed the impacts of physio-geographical pattern on spatio-temporal differentiation of regional development in China in recent 50 years, and explained its change at different development stages.The results show that the spatio-temporal differentiation in China is closely related to the physio-geographical pattern and the agricultural production could still achieve more outputs by breaking through the constrains of physio-geographical conditions. Our studies also show that the RMC can be a good tool to quantitatively assess the impact of PGP on the spatio-temporal differentiation of regional development.

In order to study the formation and evolution law of groundwater quality in the Chaobai River Basin in the changing environment, groundwater in different layers was investigated and sampled to analyze their environmental isotope (hydrogen and oxygen-18) and hydrochemistry composition. The recharge source of groundwater and the relationship between aquifers can be identified by these results.The compositions of environmental isotope δD and δ¹⁸O of rainfall and of groundwater show that evaporation occurred to different degrees with rainfall recharging to the groundwater.The shorter the distance is to the Bohai Sea, the greater the groundwater affected by evaporation. The groundwater in plain was synthetically affected by different water sources.Rainfall was the main source of groundwater in piedmont, which was affected by evaporation strongly.Results of hydrochemical analysis showed that water quality in mountain groundwater was composed of Ca²⁺ and HCO^-₃, named as Ca²⁺-Mg²⁺-HCO^-₃ type. The piedmont groundwater belonged to Ca²⁺-Mg²⁺-HCO^-₃,Na⁺-K⁺-HCO^-₃,Mg²⁺-Ca²⁺-HCO^-₃ and Ca²⁺-Mg²⁺-Cl^--SO^2-₄ type, groundwater in plain to Mg²⁺, Na⁺ and HCO^-₃ type, and groundwater in alluvium-marine sediment plain near the Bohai Sea to Ca²⁺-Mg²⁺-HCO^-₃ type and Ca²⁺-Mg²⁺-Cl^--SO^2-₄type. The hydrochemistry verified the leakage recharge was assured. The anions were high in mountainous region, low in piedmont and plain, and rose near the Bohai Sea. The groundwater type along the flow direction of the Chaobai River Basin was Ca²⁺-Mg²⁺-HCO^-₃ Na⁺-K⁺-HCO^-₃ Ca²⁺-Mg²⁺-HCO^-₃. Based on these results, a concept model of groundwater formation and water quality evolution in the Chabai River Basin was set up. The research provided scientific basis for reasonably developing groundwater in this region.

The Liaohe River Basin is one of the seven largest river basins in China; along with the socio-economic development, water environmental problems have become increasingly prominent. Recovering and protecting the aquatic ecosystem has been considered as an important research for the development of northeastern region, most important of which is eco-water requirement. In view of the present main environmental problems in the Liaohe River Basin, based on the water resources districts, the types of eco-water requirement for river basins are identified. This paper raises that the eco-water requirement for river channels in dry seasons, sediment transmission water requirement in flood seasons, sea-entry water requirement, water requirement for groundwater recruitment and eco-water requirement for estuary wetlands are important components of the eco-water requirement for this watershed at present. Aimed at the characteristic of Liaohe River Basin as a seasonal river, the minimum flow method is developed to calculate the eco-water requirement for river channels in dry seasons. The eco-water requirement for each water resource district is calculated respectively, and the eco-water requirement of the whole river basin is calculated by adding up the above water requirements, with a deduction of the overlap between the trunk stream and the tributaries. As a result, the total water requirement of Lioahe River Basin is 130.44 10⁸m³or about 48.3% of the natural flow, of which the water resource districts of the Huntai and Dongliao rivers take up more than 60% of the natural flow, the Liaohe trunk stream about 53.5% and the others less than 50%. This paper can provide a scientific reference for water resources allocation and environmental protection of the river basin.

At present, the contradiction between water supply and demand has become acute in the developed and populous areas along the Yellow River, and the destruction of the ecological environment has become increasingly serious.As most essential and important element in ecosystems, water is seriously short in the upper and middle reaches of the Yellow River, and how to appraise the loss of ecological value caused by water shortage is always a complex issue.In this paper, it was attempted to assess the ecological value loss brought by water scarcity for the yellow River.Firstly, the ecological value was classified into two groups of use value and nonuse value, and the commonly used appraisal methods in China were also introduced in this paper. In case of calculation, according to the characteristics of the upper and middle reaches of the Yellow River, eco-water requirements were divided into three parts: sediment transport water requirement, basic ecological flow, and evaporation water requirement, the corresponding methods for each type of eco-water requirements were described in detail, and were calculated respectively. And then, the loss of ecological value caused by water deficit was calculated using the Market Value Method and Shadow Project Approach. The results showed that the total ecological value loss from water shortage was 5.88 billion yuan in the upper and middle reaches of the Yellow River in 2002, the biggest loss of ecological value was caused by sediment accumulation, which was 3.53 billion yuan. The losses caused by water pollution and fishery reduction were 1.55 billion and 0.8 billion yuan, respectively. Limited by the data, other losses of ecological value such as water and soil conservation, air purification, scientific study and education were not considered in this study. Finally, it was pointed out that inter-basin water transfer is an effective way to make up the ecological and environmental loss and can make a considerable ecological profit.

Topographic index in TOPMODEL, ln (α/tanβ), is used to approximately characterize the spatial distributions of source area of surface runoff and groundwater tables in a catchment, the different algorithms utilized for computation of this parameter as well as the DEM in various spatial resolutions for such purpose can result in quite different estimations on spatial pattern and statistical distribution of the index. At present, the most widely utilized algorithm in the digital terrain analysis (DTA) method for calculating ln(α/tanβ) index is the multiple flow direction algorithm (FD8). On the basis of brief introduction to fundamental theory of FD8, a new algorithm to accurately calculate the effective contour length in the accumulated flow partitioning involved in ln(α/tanβ) computation by using internal tangent circle on conical surface method was proposed. Meanwhile the equations for calculating the cumulative upslope source area α were improved for rational computation of ln (α/tanβ) and a set of computing scheme for overcoming the noise of the abnormal grids to topographic index calculation was proposed. The new algorithm and original FD8 algorithm are both applied to two different catchments for comparison. Furthermore, we use four kinds of different resolutions (10-,20-,30- and 60-m) DEM to compute the spatial distribution of topographic index of Zhifanggou catchment. As a result, it is found that the new algorithm is more correct to express the relationship of upslope contribution area and soil water content in TOPMODEL and more accurate to reflect the hydrological similarity of real catchments. The new algorithm proposed in this paper will be useful to a certain extent to analyze watershed hydrological processes and quantify the land surface processes.

Permutation entropy is a complex parameter for time series based on comparison of neighboring values, which can measure spatio-temporal complexity of weather factors, and more importantly, whose spatial pattern can get geographical explanation. Based on the climate physics elements for time series including daily temperature and daily precipitation from 1971 to 2000, this article takes southwest of Yunnan Province as a case to study the characteristic of varied atmospheric cirulations and complex landforms, measure the climate systematic complexity and probe into their geographic causes. It is concluded that it is simple and effectual to measure the systematic complexity of climate by permutation entropy. On the one hand, the spatial pattern of permutation entropy (based on daily temperature)can reflect the complexity of regional atmospheric circulation and the significance of Ailao Mountain barrier function. On the other hand, the spatial pattern of permutation entropy (based on daily precipitation)can not only indicate the direction of the water vapour sources, but also reflect regional difference of spatial precipitation variation intensity. In a word, there is a good geographical explanation of both atmospheric circulation and localized topography to climate elements.

This article,chooses Datong city and seven counties under its jurisdiction in Shanxi province locating at the edge of the Loess Plateau and being eco-geographical sensitive region as research objects according to the long time climate survey data from 1971 to 2000, and based on the agriculture eco-climate amenity degree dynamic model established by GU Heng-yue and AI Nan-shan, and several vegetation experiments, tentatively points out eco-climate amenity degree attribution function; using which, calculates resource index,efficiency index and utilization coefficient by areas, and creatively concludes that temperature and precipitation amenity degree of Datong city and the other seven counties appear "Λ-shaped" tendency, and the peak value occurs in summer; while sunshine amenity degree of them appears "V-shaped" tendency, and the time of resource being abundant is longer, and the low value of resource amenity appears in July of every year. According to fuzzy clustering, the average efficiency index of every region by months, demarcates three types of agriculture eco-climate which are appraised respectively. The results show that the agriculture eco-climate resources of Guangling,Datong and Zuoyun counties are better, the value of C_e is between 1.5 and 2.5, especially the configuration of water and temperature resources is reasonable and the sunshine time is opulent; those of Tianzhen,Lingqiu and Yanggao counties are common, the value of C_e is between 1.0 and 1.5, water and temperature are synchronous, but the sunshine time is shorter than the former; and those of Datong city and Hunyuan county are the poorest, the value of C_e is less than 0.5, especially the sunshine time appears short throughout the year.

As an index denoting vegetation cover, NDVI is influenced by many climatic factors such as precipitation and average air temperature. In this paper, NDVI is calculated on the basis of waveband characteristic of NOAA/AVHRR data (National Oceanic Atmospheric Administration/Advanced Very High Resolution Radiometer) for the Yarlung Zangbo River Basin. Then,the spatio-temporal change of NDVI is analyzed. The basin's NDVI is in consistency with season from 2001 to 2003. High value zone of NDVI is mainly distributed in the lower reaches and part of the middle reaches. Meanwhile, point data of principal climatic factors (precipitation and average air temperature) are interpolated to spatial grid data with Kriging method consistent with NDVI based on DEM of the Yarlung Zangbo River Basin. Then, the relation of NDVI and precipitation or average air temperature is analyzed with F checking and two-sample variance test in the basin. The result is P=0, which shows that correlation analysis has higher confidence. The linear and logarithmic correlation of NDVI and precipitation or average air temperature is analyzed at confidence level of 0.05. The conclusion is that NDVI and precipitation and average air temperature in the basin vary with seasons and are closely correlated. The linear correlation coefficient of NDVI and precipitation is 0.8, and that of NDVI and average air temperature is about 0.77. And the logarithmic correlation coefficient of NDVI and precipitation is 0.71, and that of NDVI and average air temperature is 0.7.

In this study, soil erosion is divided into natural soil erosion and anthropogenic soil erosion. The natural soil erosion is ubiquitous on the earth since the earth came into being. Erosive and accumulative topographic features, such as peneplain, river terrace, sedimentary basin, etc. , have disclosed the existence of natural soil erosion in the upper and middle Yangtze River since the early Quaternary. Using the thickness, dating and area of sediment deposited in the Dongting Lake, Poyang Lake and the ancient Yunmeng Lake, the specific sediment yield of the watersheds draining into these lakes is found to be 264.2t/km² · a, 312.5t/km² · a and 297.0t/km² · a, respectively. Moreover, the natural sediment yield from some experimental plots located in west Sichuan and the Three Gorge areas is estimated to be about 342.0t/km² · a and 75~270t/km² · a, respectively. Thus, the natural sediment yield ranges from 264.0t/km² · a to 342.0t/km² · a in the upper and middle Yangtze River, which is about 50%-60% of the modern sediment yield in the area. The results of this study will help us to understand the characteristics and tendency of the modern soil erosion in the upper and middle Yangtze River, and will be a sound background for realizing the goal of conserving eco-systems and building an environmental management in the area.

By sampling along a representative section across the shelterbelt of Baotou-Lanzhou Railway at Shapotou area, grain-size characteristics of aeolian deposits in the shelterbelt and the influences of landform were studied. The total 20 sampling points covered various landform sites such as the windward and leeward slopes of sand dunes, dune crests, and inter-dune depressions.Three of which were located on the surface of a mobile dune at the upwind edge of the shelterbelt, and the other points were located in the straw checkerboard and artificial vegetation belt. The results show that clay and silt contents in surface soil increase greatly and mean grain-size decreases from moving sand area to the artificial vegetational belt due to the changes of the surface properties, and sorting becomes poor. It seems that silt contents decrease with relative height of surface in the shelterbelt; mean grain-size and sorting increase with surface height. Statistics further show that mean grain-size, sorting coefficient and silt content were well linearly related to the relative elevation. Dependence relation between clay content and landform was not observed. The possible cause is that clay material in the deposition was mainly sourced from general dust events. The influence of the landform on dust deposition is very limited. Clay sediments tend to cumulate in the shelterbelt under the protection of the straw checkerboard and artificial vegetation but hardly accumulate in moving sand area due to intensive aeolian activities. Vertically, silt content is high and sorting is poor in the surface 5 cm layer; below this depth silt content decreases and sorting becomes well. The grain-size profile varies among landforms. Estimated aeolian deposition rates around the crest of fixed dunes average 0.147 cm per year, versus more than 0.588 cm on the leeward side and in inter-dune depressions. As a whole, this study revealed the changing regulation of grain-size characteristics along the direction of NNW-SSE in the shelterbelt of Baotou-Lanzhou Railway at Shapotou area, demonstrated the relations between grain-size characteristics and landform, as well as the relations between deposition rates and landform. The results objectively reflected the effects of the landform on aeolian deposition in the shelterbelt.

Based on the field investigation of community plots, two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) were applied to analyse the ecological relationships on subalpine meadow communities in Yunding Mountain, Shanxi province. It was showed that: (1)five meadow communities of 36 samples located in different altitudes were recognized by TWINSPAN and characteristics of the communities were described respectively, including distribution of dominant species and relationship with environmental factors. All results were confirmed by the two-dimensional ordination diagram of DCA.(2)The environmental variables, such as altitude, grazing intensity, moisture and heating conditions, were the major environmental factors affecting community's change. The results of DCA ordination showed that the five meadow communities had their different distributions along their environmental gradient. The first axis and the second axis of DCA reflect the gradient of elevation, grazing intensity and soil water conditions of the communities. (3) The distribution patterns of dominant species were highly similar to that of the communities. With the increase of the altitude, Kobresia bellardii, Carex lanceolata, Festuca ovina and Taraxacum mongolicum gradually took the dominant status on the communities, which showed that community distribution patterns were coordinate to the zonal vegetation distribution patterns due to the increase of elevation and the decrease of human interruption. (4)The difference in species diversity of the community had close correlation mainly to the specific evenness and grazing intensity, meanwhile, also had close correlation to the meadow habitat. Species diversity of the meadow distributing in the semi-sunny slope, semi-shady slope, shady slope and high altitude area, due to its better water supply and temperature environment, was much richer than that on the sunny slope and low altitude area. Also habitat conditions degraded because of intensive grazing. Meanwhile, species diversity plays an important role in the development and distribution of the meadow communities. (5) Grazing has an obvious interruption effect on the succession of subalpine meadow communities in Yunding Mountain, which has validated the previous researchers' opinions.

The Liupan Mountains are situated in the intersection of Ningxia Hui Autonomous Region, Shaanxi, and Gansu provinces, between 35°-36°10'N and 105°4'-106°30'E. The region is not only the transitional zone between semi-humid and sub-arid climate, but also has rich biodiversity on the Loess Plateau, even in Northwest China, with regional vegetation distributing from warm temperate deciduous board-leaved forest zone, forest-grassland zone to desert-grassland zone. Studies on the plants' floras of Liupan Mountains show that it comprises 836 species of vascular plant, belonging to 93 families and 359 genera. Its floras can be attributed to the following categories:Loess Plateau subregion, North China region, Sino-Japan forest subkingdom, and Holarctic kingdom. There are 13 distribution types and 12 subtypes of genera of seed plants, of which North temperate elements play an important role in the flora. The plant genera flora on Liupan Mountains connect closely with other floras but have little endemic genera. The floristic affinities of the study area with neighboring three mountains (Taibai, Xiaolong and Zhongtiao mountains) are close, and their coefficients of plant genera flora all exceed 60%, indicating that these mountains have similar bio-climatic conditions without any clear vicariance. While the coefficient with Helan Mountains is under 60%, because the Helan Mountains are located in arid desert and semi-desert region and it is supposed that there is intense vicariance in nature in the development of the Yellow River in Ningxia and Gansu.

Soil and water loss in hilly area of the Loess Plateau is affected by many environmental factors, such as climate, vegetation, soil, terrain and so on. Severe soil and water loss is also blamed to irrational land-use pattern and infeasible spatial allocation of tree, shrub and herb plants. How to adjust land use structure and how to distribute tree, shrub and herb plants over space is imperative in the Loess Plateau. In present study, four key ecological factors affecting the growth and distribution of plants were chosen, including elevation, slope degree, slope aspect and precipitation, and then a decision table was established for spatial optimum allocation of plant species. The study area was divided into five main groups and eighteen sub-groups based on multi-criterion decision analysis (MCDA) and GIS. In addition, by using cluster analysis and area statistical analysis in GIS, the main and sub-groups were distributed to specific spatial cells, and the area of each group was calculated. This article presents the following viewpoints and conclusions: (1)In order to avoid blindfold artificial plantations and grain-for-green projects, adaptability of species and plant communities to the four ecological factors was analyzed through MCDA and experts knowledge. (2)Under the condition of sticking the principle that the economic benefits, social benefits and ecological benefits are synchronistically improved, economic plants and medicinal plants were allocated to adaptable cells according to their ecological requirements. (3)The decision table showed that land with a slope of more than 15° to be shifted to forest and grassland. Meanwhile, spatial cells for natural restoration were restricted to the area with slope more than 35°, accounting for 9% of the total study area. (4)The results indicated that economic forest/agro-forestry ecosystems and the farmland/courtyard-economy ecosystems should be the two major spatial allocation models, covering 76.02% of the whole area. And the other three models covered about 25% of the whole area. Spatial allocation of plant species is not only beneficial to eco-environmental improvement, but also useful to regional planning in agriculture.

Spatial distributions of total nitrogen(TN) in soils are difficult to estimate because of their inherent spatial variabilities and lack of sufficient sample data.Soil-landscape model,based on parent material and topographic factors,was generated through applying GIS spatial analysis technique and a digital elevation model (DEM) in large areas.Based on 151 sample data, spatial distribution characteristic of TN was studied.Correlations between TN and topographic factors were analyzed and a regression model was established to predict TN content through linear regression analysis.The results for surface soils (0~20cm) showed that the average content of TN was 1.06g/kg in topsoil,with TN content between 0.5g/kg and 1.0 g/kg occupying the largest area (1580km²,49.3% of the total area) and that over 2.0g/kg the smallest(127km²,3.9% of the total area)in spatial distribution. Also,soils derived from sandstone and shale had the lowest average TN content (0.88 g/kg soil),soils developed on phyllite showed the highest average TN content (1.35 g/kg soil).Aspect among topographic variables had an important effect on TN content.The correlations of TN content with parent rocks,elevation and aspect were positively significant (P<0.05),slope exposure had the highest correlation with TN content (r=0.62).The correlation of TN content with slope was insignificant (r=-0.03).In the soils of the whole study area,the step regression analysis of the TN content, topographic factors and parent rocks showed that elevation,slope exposure and parent rocks were the best factors for predicting the TN content in topsoil (P<0.05).The multiple linear regression model is: TN=0.095+0.005×parent rocks+0.001×elevation+0.115×slope exposure classification n=113 R²= 0.637 The spatial distribution of TN content could be predicted by using a multiple linear regression model and DEM ( with a 30m×30m grid).

Exchangeable phosphorus can be estimated by an infinite dilution extrapolation approach (IDE) and the first procedure of Hieltjes and Lijklema approach in the superficial sediments of shallow lakes in the middle and lower reaches of the Yangtze River. Variation range and average amount of the NH₄Cl-P which can be determined by H-J approach and the IDE-P determined by IDE approach are studied for sediments with different pollution conditions. In addition, the quantity of the two forms of exchangeable phosphorus existing in those sediments is compared. The correlation between NH₄Cl-P and IDE-P and the proportion of NH₄Cl-P to IDE-P are analyzed. Recently, many researchers have focused their work on the effect of soil adsorption characteristics on soluble reactive phosphorus in solution. Some of the soil adsorption characteristics are estimated by soil test phosphorus (STP) and the degree of phosphorus saturation (DPS). In order to discuss the relationship between the two adsorption characteristics and the two speciations of exchangeable phosphorus, their linear correlations are discussed. The results are displayed as follows: (1)The potential exchangeable phosphorus determined by IDE approach and the exchangeable phosphorus quantified by the first step of H-J approach indicate that the contents of both are higher in the sediments which are seriously polluted and lower in those of slightly polluted. (2)The contents of IDE-P are higher than that of NH₄Cl-P in all kinds of sediments. The proportion of NH₄Cl-P to IDE-P verified greatly in different kinds of sediments. Because IDE-P is higher exactly in characterizing exchangeable phosphorus and more complex in procedure compared to the characteristics of NH₄Cl-P, proper approach can be chosen to make their results accord to the reality. (3)There are a good correlation between the two forms of exchangeable phosphorus and the soil adsorption characteristics of STP,DPS and other physio-chemical properties.

In order to screen the potential hy peraccumulators, the concentrat ions of Cu, Mn and Zn in 24 dominant plants grown in areas near abandoned Mn, Pb/Zn and Aumines in Nanning City of Guangxi Province were investigated. The results show that most plants contained high concent ration of metals resulting from the increased metal concent rations in the soils near the mines. Mn concentration f Mn-mine soil (2415.0 mg/kg) , w hich was 14.0 times greater than Mn backg round value of Guangxi soil, was higher than that of Pb/Zn-mine soil (687.5 mg/kg) and Au-mine soil (487.2 mg/kg). Most of the investigated plants grown on the Mn mine contained higher concentration Mn in the aboveground tissue (909.0~27514.0 mg/kg) than that (143.6~4388.0 mg/kg ) grown on other mines.

In this paper, the authors made a fractal analysis on the spatial structure of tourist scenic spots systems of Nanjing, based on a latest tourist resources survey, to explore the characteristics of spatial structure.The authors chose 14 leading tourist scenic spots as samples to analyze random aggregation fractal dimension, grid information fractal dimension and correlation fractal dimension of the spatial structure of tourist scenic spots systems. Through analyzing fractal dimensions and individual fractal dimension coordinate, the author concluded that it is feasible to apply fractal approach to study the spatial structure of tourist scenic spots systems in Nanjing. Analyses of three fractal dimensions all lead to the same conclusion that the tourist scenic spots systems in Nanjing have a fractal spatial structure and show a tendency of self-organization optimization. Hierachical centers and spatial geometrical centers overlap each other and form a mature fractal spatial structure. Pillar attraction dots in each tourist spot are close to each other, providing ideal order and sequence and well-arranged spatial structure, thus leading to an optimized independent operation. To be exact, the random aggregation fractal dimension D=0.6818, less than 1. The spatial structure of the whole tourist spots network shows a strong random aggregation while the density of tourist spots lowers down quickly from the center to its surroundings. Grid information fractal dimension also presents a highly-centered layout of tourist spots in Nanjing. Its value approaches 1, which shows that tourist spots gather along certain directions in spatial arrangement. And the correlation fractal dimension reveals that the spatial structure of tourist spots is of a multi-fractal feature with varied fractal structures, which means that the spatial structure of the system has not reached an ideal self-organization optimization, or retrogradation has occurred to some degrees.The tendency of self-organization optimization has been interrupted by some unexpected factors and the spatial structure needs new adjustments.

To study residents’ perception toward tourism impact is of practical significance for developing tourism industry.Taking Luya Mountains Nature Reserve as a case, the background characteristics of the residents engaging in tourism industry and the perception toward 27 indices about tourism impact are investigated on the spot, and the relationship between their characteristics and the perception level is analyzed by two-way indicator species analysis (TWINSPAN) and detrended correspondence analysis (DCA) in the paper.The results show that: (1) TWINSPAN is a kind of better classifying way, and can divide 32 samples into mature and active group, immature and active group, retreating group and apathy group. (2) Each group has its own distribution area and borderline on the DCA ordination figure. Axis 1 of DCA reflects the samples' sex and income mainly, and Axis 2 shows their education level. (3) The distribution pattern of dominant factors decides on the distribution pattern of the samples' groups to a great extent. (4) The classification of TWINSPAN needs to combine with actual fact, and DCA can eliminate "arch effects" obviously. The result of TWINSPAN is consistent with that of DCA, and both are comparable. Both can show the ecological relationship between the residents engaging in tourism industry and their perception toward its impact objectively. However, it still needs farther studies on how to express their interrelationship more directly.

Upon entering the 21st century, planning and building of eco-city has not only become a hotspot of research, but also gradually got to the common understanding of the whole society. It is the most important of all to renew and upgrade the depurative ability of urban-compound-ecosystem by building eco-hub. This article puts forward the conception and meaning of eco-hub, summarizes its five categories of functions, including landscape axis effect, climatic modification effect, intensive economic development effect, biodiversity effect and eco-safety effect. It emphasizes the necessity to build eco-hub, and taking Nanjing city as an example, analyses the conditions, schemes and corresponding measures for eco-city building.The following conclusions are drawn: Firstly, with the development of modern eco-city, it is necessary to plan and build eco-hub. We should build a multiple ecosystem in order to solve questions brought by urbanization and industrialization. Being the "CBD" of this system, eco-hub must be built first. Secondly, eco-hub becomes the key step to upgrade the function of multiple ecosystem because by its powerful function it can combine each natural element and improve its efficiency. This can make full use of multiple eco-system, and the city environment can turn better and better by natural function instead of manpower. Thirdly, despite of rapid development of economy and technology in China in the new century, building eco-hub is a long and hard work. Each of us should do something for it.

Although the current practice of administrative division adjustment in China promotes regional governance and urbanization economies, it does not effectively resolve the conflicts between central city and surrounding county-level cities. This paper examines the influence of administrative division adjustment on economic development in Changzhou, Jiangsu Province, and analyzes problems such as key sectors, spatial distribution and location choice related to the city's development zones. This paper focuses on industrial and urban spatial development issues arising after the administrative merger in 2002, which converted Wujin into a district of Changzhou. The city in this case has fast-growing market forces but lacks efficient governance, which is a quite common situation for cities in the Yangtze River Delta. We examined the major institutional, policy, socio-cultural, and spatial planning factors underlying these problems. We argue that the incongruence between administrative division adjustment and the existing institutional framework is the fundamental source of conflicts among the constituting parts of the city. Inconsistencies among spatial plans made by different government bodies are manifestations of these divides. They also undermine implementation of regional plans and policies. Finally, from the perspectives of institution, policy, and space, we explored strategies for the spatial integration of economic development in Changzhou. Institutional adjustment is essential for the city to achieve sustainable development and enhance economic competitiveness. Policy making should emphasize regional development goals, and policymaking process should combine the bottom-up and top-down approaches to create a good framework for diverse but coordinated economic activities. The regional perspective should also guide the spatial integration, and spatial planning that has strong legal and intellectual bases will play a key role in achieving city-wide coordinated development in Changzhou.

This paper analyzes the spatial pattern of financial services industry and the impact of enterprises' financial service consumer behavior on that by using first-hand data obtained through questionnaires and in-depth interviews. The city and second-hand data are from socio-economic statistics(1991-2004)and second basic units census(2001). The results are as follows: Firstly, a decentralized spatial pattern of financial services industry in Dongguan has been formed as nearly the same as that of secondary industry, which means that these two industries are linked closely to each other. Secondly, the enterprises invested by Hong Kong's and foreign capital are now searching the opportunity for supplying the financial services in Dongguan, Pearl River Delta (PRD) and the whole country. Except PRD, Hong Kong and other areas are becoming the main sources of financial services for enterprises located in Dongguan. Thirdly, the producing bases of multinational corporations, successful Hong Kong enterprises and town-owned industrial firms facilitate the spread of financial services in the town by making the consumption standard and the financial services normalized. As a result, the decentralized spatial pattern of financial service industry has come into being. Finally, the consumer behavior of different enterprises is dissimilar, so is its spatial effect. Comparatively, the 'park-style’ consumer behavior of financial services of town-owned firms mainly represents the distinction of less out-of-town consumption and its facilitation to the development of financial services is limited to the scale of township. While the multi-spot style' consumer behavior of multinational corporation producing base plays a key role of causing the spatial centralization and decentralization of financial services with different spatial dimensions at the same time.The 'twin-spot style’ consumer behavior of enterprises in Hong Kong, oriented by extensive and in-depth investment and trade between Hong Kong and Guangdong Province, is the micro behavior basis of two processes, which are the industrialization of Pearl River Delta and the transformation of Hong Kong's economy from manufacturing to services industry and the medium for establishing closer financial linkage between Hong Kong and Pearl River Delta.

From the perspective of potential accessibility, according to the transport condition among the regions, this paper builds up the network model, and calculates, forecasts and analyses the potential spatial accessibility pattern in Guangzhou-Hong Kong Urban Corridor with integrated GIS tools, based on analyzing the current accessibility data in the landway transport network in Guangzhou-Hong Kong Urban Corridor, using the shortest time distance index and the weighted average travel time index. The latter index uses population in the future as its weighted factor. As a result, the potential accessibility of landway transport network in Guangzhou-Hong Kong Urban Corridor presents a concentric circle spatial pattern either the shortest time distance index or the weighted average travel time index, and the inner accessibility level is better. The accessibility level goes worse from the center to the periphery. The author transforms the results of these two indices into accessibility coefficients for the purpose of comparison.The results show that the accessibility status of the south corridor is improved and the north one is weakened taking the potential population factor into account.Finally, the potential accessibility level is compared with the current one. It is suggested that the former is more balanced that the latter, the overall accessibility level is improved, and the lower the original accessibility level is,the more it improved.

According to the rule and framework of urbanization and eco-environment coupling, the system dynamic model of the coupling system between urbanization and eco-environment in Jiangsu province has been designed by means of SD method. Based on Jiangsu’s serial statistical data from 1990 to 2003, the five scenarios of the coupling models during 2000-2015 have been simulated. The results show that: Firstly, for there exist complex, nonlinear and changeable characteristics of the coupling system between regional urbanization and eco-environment, in terms of SD merits, it is applicable for the SD to deal with the complexity resulted from regional urbanization and eco-environment coupling. The accuracy assessment with historical data covering 1990 to 2003 indicates the SD model is reliable to a certain extent, which can reveal some complex actions of the coupling system and evaluate the potential effects that urbanization intimidated eco-environment. Secondly, there exist significantly differences among the five development models, which show both comparative advantages and drawbacks. Thirdly, according to the characteristics and regional disparities of Jiangsu development and the general rule of world urbanization, it is revealed that only when either population urbanization model or society urbanization model to be adopted correspondingly can the sustainable development among population, economy, urbanization and eco-environment be realized.

The spatial structure of metropolitan area is the most integrated and most diverse part of urban system. It is composed by different ranks of spatial elements such as cities (nodes), spatial flows (functional linkages), channels (linkage axis) and action fields (the attraction range of each city) and so on. The spatial structure of metropolitan area is represented as the spatial combination relationship of three factors including point (city and urban system), line (economic linkage channels) and surface (urban hinterland). Based on the statistical data of Wuhan metropolitan area in recent years, using SPSS mathematical statistical technique and GIS spatial analysis function, we build an economic linkage intensity model and investigate the dynamic characteristics of the spatial competition and its range of Wuhan metropolitan area. It is found out that: (1) there are some main linkage directions in the external economic linkage of central cities, and its temporal inertia and spatial polarization are also very obvious; (2) the external economic linkage intensity of central cities is distance decay, which leads to a regional layered spatial structure. Then from the aspects of point, line and surface, we build and compute some useful indices which are the centralities of economic linkage node (central city), the network connectivity of economic linkage channels (transportation network) and the regional organization of economic linkage range (urban hinterland). With the aid of these indices, we can quantifiably analyze and point out the hierarchical characteristics of the economic linkage spatial structure of Wuhan metropolitan area. It is concluded that: (1) the centrality hierarchy of central city is quite different, their spatial distribution is uneven and has close relationship with transportation location; (2) the development and service function of linkage channel is hierarchical, and two inter-city transportation channels have been formed significantly; and (3) the influence range of economic linkage is closely related to external economic linkage intensity of central cities, and it is also greatly affected by its regional natural condition and administrative regionalization.

There is an ecotone connecting farming region and pasturing region for northern agro-grazing ecotone. Its ecological function consists of conserving water sources, checking the wind and fixing the shifting sand, purifying air and maintaining biodiversity.Grassland is not only one of the important ecosystems, but also a background vegetation. Over the past decades, human activities have caused great land cover changes, such as desertification, grassland degradation, and sandy. Therefore, accurate and timely monitoring grassland is of critical importance for utilizing and administering grassland, developing pasturage and improving ecological environment. Using MODIS remote sensing data for the year 2005 and the ground measured grass yield of the corresponding period, linear regression model,non-linear regression models and BP neural network model were respectively established, to express the regression relationships between ground truth data and vegetation indices in this paper. Some conclusions are drawn as follows: (1) Regional models are better than whole-area general models. It is reasonable for the four grassland areas, and the regional models can better describe grass production.(2) Models based on BP neural network are better than linear regression models and non-linear regression models in fitness accuracy. Its decision coefficient increases by more than 3%, and the highest is 6.92%. Moreover, by precision validating, we find its root mean square error and relative errors are smaller, the models precision increases by more than 2.5%, and the maximum increases 23.22%. It is obvious that models based on BP neural network are most suitable for monitoring grass production of northern agro-grazing ecotone, and it can meet the need of estimating of grass production in northern agro-grazing ecotone.(3) The suitable vegetation indices for monitoring grass production of northern agro-grazing ecotone are NDVI and SAVI.(4) With the accumulation of the temporal scales data, further studies may focus on input data for BP neural network model. For example, input data may adopt soil moisture index and temperature and precipitation, and so on, which may further increase precision of models, and approach actual grass production for monitoring results.

The theoretic and methodological research of map generalization is an important field in cartography and geographical information systems. The difficulties of map generalization lie in selectively omitting some features while maintaining the overall characteristics of their spatial distribution. Simplifying drainages is an important aspect of map generalization.Structural patterns and density differences are salient characteristics of drainages, which should be maintained in generalized versions. This paper proposed a new method to generalize dendritic drainages while maintaining the density differences between sub-drainages, which is based on the layered division of the number of retained rivers in river trees. We analyzed the layered structure of dendritic drainages and their density differences, and found the density differences inside a drainage come from the differences of the number of tributaries of its sub-drainages. A method to allocate the number of retained rivers is accordingly proposed, which divides the overall retained number of sub-drainages of a drainage according to the ratio of the number of the tributaries. The structured drainage generalization is executed in three steps. Firstly, the river entities and river trees are constructed, and the number of tributaries for each river is counted. Then the number of rivers to be retained in the generalized version is computed according to the Square Root Law. Lastly the number of retention is divided among all of the drainages according to the number of their tributaries, the mainstream of a drainage with big length and spacing is selected, and the allocation and selection are recursively executed in the lower layer until the number of the selected rivers reaches the limit of the drainage. The method was implemented as plug-ins in Java Environment. Experimental results are compared with the hand-made generalized maps. A case study of drainage generalization showed that the method created acceptable results and the density differences among drainages were maintained effectively.

This paper presents a new method to calibrate urban cellular automata (CA) using genetic algorithms(GA).The GA is used to find the optimal parameter values so that CA models can simulate urban expansion in a more realistic way. Traditional multi-criterion evaluation (MCE) and logistic methods have limitations for deriving the transition rules of CA models. The variables should be independent so that the parameter values (coefficients) can be properly estimated by regression analysis. This assumption is not true in most situations. The limitations can be overcome by using GA to estimate these parameter values for these correlated variables. When calibrating urban cellular automata with GA, the parameters of CA models are set to the chromosomes in GA program.The real number encoding way is used to encode chromosomes. The fitness function is defined with mean square error between simulated and actual urban forms.The initial population is set to be 50 randomly. And crossover probability is set to be 0.9, and mutation probability is set to be 0.01. The elitist selection is used to heredity the better individual.If the fitness does not change in the past 50 generations, the genetic procedure will be finished. After properly encoding the chromosomes, the optimal parameter values are automatically found by the evolutionary approach. This method is applied to the simulation of urban expansion in Dongguan, a fast developing city in the Pearl River Delta in South China. The model is able to simulate urban development in 1988-2004 by using the training data from remote sensing data. The analysis indicates that the proposed model can produce better simulation results than MCE-based CA models and logistic calibrated CA models. Moreover, the parameter values can be used to explain the relationships between spatial variables and urban development.

Place names are certain exclusive names of the physical or humanic geographic entities of specific space locations given by people and they are important signs through which the mankind knows the nature and human activities. As the language fossils, geographic names have the instructive functions to different historical periods and different regional social cultures. Located in the southern border area of China, Guangdong province which is affected by Central Plains and overseas culture deeply at the same time has its own peculiar development courses. This article adopts the GIS technology and establishes a Guangdong geographic name Yuan database (GEODATABASE) on the mathematical statistic basis. It also deals with the databases to output the straight side topic maps and other special maps which needs other special maps through ARCGIS GEOPROCESSING,SPACIAL STATISTICS TOOLBOX and ANALYSIS TOOLBOX according to the attribute essential factors as well as carries on dividing and color chromatic aberration processing. Finally, the place name landscapes of Guangdong demonstrate the peculiar geographical environment characteristics of the south of the Five Ridges and historical development characteristics: no harmoniousness in space distribution, varieties of common names and proper names, distributing concentration of neat head(qitou) place-names which have many ethnicities and dialects. The article also carries on geographical zoning on the basis of counting, and divides the geographic names Guangdong province into four big areas according to the types, namely the Hakkas(Kejia), the lucky man(Fulao), the Zhuang language(Zhuangyu) and the Cantonese(Yueyu) geographic name area, and they also respectively displays the core-edge proliferation pattern in space.

According to the Law of Environment Assessment of China implemented in 2003, land use planning must conduct an assessment of its potential impacts on the environment, as to avoid the adverse environmental impacts of land use restructuring when the land use planning is implemented. For this purpose, this paper developed a procedure and proposed 11 indicators to estimate possible influences of the implementation of land use planning on the ecological security, environmental health, and land resources. These indicators cover five key aspects that may be affected by the implementation of land use planning, including ecological protection, land degradation control, arable land protection, built-up land expansion and its effects, and ecological risk of land reclamation. Further, as a case study, the procedure and indicators were applied to the China's Integrated Land Use Planning of 1997~2010, to examine the feasibility and reliability of the approach and indicators. The results of the case study show that implementation of the land use planning would greatly alleviate the environmental problems particularly of land degradation, enhance the ecosystems service functions, and improve the quality of arable land although the farmland area might decrease due to the built-up land encroachment. It concluded that the indicators can well reveal the potential effects of the implementation of land use planning on the environment, ecosystems and land resources, and thus the assessment is useful and valuable in supporting the land use planners or policymakers to sufficiently consider the environment issues in the formulation and implementation of land use planning.

Land consolidation plays an important role in promoting rational land use and improving ecological environments. It produces the changes of land uses and their spatial structure to result in the changes of landscape pattern and ecological effects. Therefore, it is very important for planning and designing eco-environmental evaluation of land consolidation so as to study its landscape-ecological effects. Taking Huairou District in Beijing as an example, the changes of land use structure and landscape patterns for land consolidation are analyzed using GIS combined with method of landscape ecology in this paper. The following conclusions are drawn. The land consolidation converts most of other land uses into cultivated land, whose area is more than 70% of the project area. In this process, most of the unused land was transformed into the cultivated land, some forest land was changed into cultivated land. Whereas residential and industrial areas changed indistinctively. The number of land use patches and their density decreased by over 50%, the areas of average patch, the largest patch and the least patch increased 1.2, 0.4 and 79 times compared with those before land consolidation. However, the patch variance coefficient reduced by 24.18%. In the whole landscape, the land use patches became simple and regular, landscape edge density, shape index and splitting index decreased over 29%, whereas aggregation index slightly increased, when land consolidation has been finished. Land consolidation reduces landscape fragmentation. At the same time, it also causes decrease of landscape diversity. The Shannon's and Simpson's diversity index and evenness index reduce over 30%. Based on the characteristics of land consolidation and results of the previous researchers, the common 10 indexes of landscape effect analysis including patch level and landscape level are summarized.

Construction land expansion is one of the notable features of urbanization.Analyzing the spatial-temporal features of construction land expansion can enhance the understanding of the nature of urbanization and provide with the grounds of decision-making for urban sustainable development. Based on the review of related research on construction land expansion at home and abroad, this paper takes Changsha urban area as an example, which is one of the most important cities in Central China.First, data on the variation of construction land in Changsha are obtained by employing the statistic and analytic function of GIS on the spatial data from remote sensing image data in different periods.Then the characteristics of construction land expansion are identified by using several methods in analyzing the spatial-temporal features of Changsha urban area from 1986 to 2004, which include expansion speed, expansion elasticity, fractal dimension, and rose map. The results obtained show that, during the last 20 years, the area of construction land has almost doubled, which is more obvious during the 2002-2004 period. Considering the relationship between the construction land area and population, the expansion speed of the construction land is far beyond that of the population, of which the erosion of arable land is most prominent. At present, the city sprawls by the way of low-density fill and the main direction of city expansion is NW270°-295° and SE165°-280°. Besides economic development and population growth, policy is also one of the important driving forces in construction land expansion. Especially in recent years, policy factor turns out to be the most determinant factor. In the future, the expansion mode of Changsha city will be that of mono-centric groups, and the direction of expansion will be more rational.

Using a large data set gathered in household surveys conducted in Chongqing from December, 2003 to April, 2005, this paper examines some important aspects of agricultural land use under household responsibility system(HRS). The results indicate that the general trend is that the rate of land transfer is higher in the Yuxi economic corridor than in the metropolitan area, which, in turn, has a higher transfer rate than the Three-Gorges economic zone. Gradually, the mode of subcontracting has been accepted and adopted by the local farmers, and the modes of land renting and alienation in exchange of cash are beginning to appeal to some of the households. Land renting or leasing, is the chief form of land transfer in the metropolitan area, while most farm households in the Yuxi economic corridor and the Three-Gorges economic zone prefer the form of subcontracting, which does not terminate the original contract relations. The responses of land use patterns and land use environment to land transfer are noticeable in the sampling villages. Most of the transferred farmland in the metropolitan area is allotted to non-agricultural uses. In the Yuxi economic corridor and the Three-Gorges economic zone, only a small portion of the transferred land is used for non-agricultural uses and the intensiveness of land use is enhanced for most of it without major changes in land cover.The conditions of land tenure control the scope of land transfer without great inter-regional variation. The degree of development of the rural land market not only impacts the scope of land transfer in the region, but also constitutes the fundamental causes for the inter-regional variation in land transfer scope and in the evolution of transfer modes. Social security plays a decisive role in whether the farmers are willing to quit farming and in what way they will quit farming. Management of land transfer, which includes rights security management and land use management after the transfer, is essential for standardizing the behavior of the principal agents in land transfer, for reducing disputes in transfer and ensuring the smooth proceeding of land transfer according to law. Understanding the psychology of the farm households under the changing macroeconomic environment and their responses to the driving factors for land transfer is of tremendous significance to the establishment of a market law-abiding and human-oriented system for land transfer in China.

Xinjiang, the largest provincial region in China, is abundant in geological heritages. Influenced and restricted by the geological conditions and the geographical environment, the distribution of geology heritages in Xinjiang has an obvious spatial differentiation. Considering the deep fracture and the geostructure unit, which are the key factors influencing the spatial distribution of geological heritages, this thesis innovatively established the multi-level system of spatial pattern of geological heritages in Xinjiang. This system includes Altay, Zhunggar, Tianshan, Tarim and Kunlun-Altun, the 5 divisions of grade Ⅰ-- geological heritage belt; Southern Altay, Northern Altay, Western Junggar, Middle Junggar, Eastern Junggar, Northern Tianshan, Southern Tianshan, Western Tarim, Eastern Tarim, Western Kunlun, Middle Kunlun and Eastern Kunlun Altun the 13 units of grade Ⅱ-- the geological heritage area; and 35 units of grade Ⅲ-- the sub-geological heritage area. It designed 4 categories of quantitative indicators -- quantity, grade, type, protection condition, and 8 specific indicator factors -- quantity proportion and density of geological heritages, the proportion of nation and world-class geological heritages, geological heritage abundance, the average road distance from neighboring towns, the relationship with peripheral tourism resources, the proportion of protected geological heritages, the proportion of developed geological heritages. These indicators gave a comprehensive and quantitative characterizations on the spactial pattern of geological heritages in Xinjiang, and then, it was used to classify the units of Grade Ⅱ. These jobs laid the foundation of the research on the protection and exploitation of geological heritages in Xinjiang, which was based on geological heritage resources coupled with the human-land relationship. The results show that, in the cells of grade II, Northern Tianshan, Western Kunlun, Southern Tianshan, Northern Altay are identified to be excellent sites, while Turpan-Hami, Middle Zhunggar, eastern Tarim, Eastern Kunlun-Altun, Middle Kunlun, Western Tarim to be good; Southern Altay to be medium and Western Zhunggar, Eastern Zhunggar to be poor.

The assessment on regional desertification degree is very important to prevent and control desertification. However, there are some problems about the assessment method of regional desertification degree. For example, the ecological meaning of spatial distribution of different types desertified land was ignored. And the influence of spatial distribution of different types of desertified land on overall regional desertification degree was neglected. In addition, while the area of every type of desertified land in the regions assessed is equal the assessment model fails to work. Therefore, the factor of ecological meaning of land spatial distribution on different types of sand and the factor affected the regional desertification degree should be added to the regional desertification assessment methods. To solve these problems, we selected the landscape pattern index and aggregation index according to landscape ecology principle, and applied them to construct regional desertification degree assessment model through RS and GIS technology. Finally the regional desertification degree in the six counties of Hunshandake Sandy Land was assessed by applying the model. The result suggested that this method can distinguish the desertification degree in different periods. Therefore, according to the assessment result,Zhenglanqi should enhance the control of desertification,and Guyuan county and Taibus should prevent regional desertification.

Coniferous forest in Helan Mountain is the relatively rare forest ecosystem in northwestern China. For the conservation of forest, the structure and floristic composition of coniferous forest have been studied. Based on principal components analysis of forest structure, mainly four kinds of forest could be obtained, that is diameter at breast height (DBH) of trees mostly less than 10 cm, DBH of trees mostly between 10 and 20 cm, DBH of trees distributed approximally equally and DBH of trees mostly greater than 30 cm. The result mainly reflected the times after prohibition of logging, and also indictated the effects imposed by altitude. Based on TWINSPAN analysis of species composition, six plant associations could be found, which were mainly influenced by altitude. The species density in spruce-moss forest was the minimum in the whole coniferous forest. Ascending from spruce-moss forest, the forest disappeared gradually and overlapped with alpine bushes and meadow, with species density increasing. Decreasing with altitude, the floristic composition changed and species density increased. Down to the lowest pine forest, the species was most abundant. The comparison of the classification of forest structure with that of species composition indicated that, though the criteria of analyses were different and the features of forest were viewed from different sides, there existed some inherent relations between foreset structure and floristic composition. The forest structure and species composition were all mainly influenced by altitude. When the forest structures were similar, several plant associations could be found, but one assicoation always belonged to single forest structural type.

Soil erosion in black soil region in Northeast China leads to soil redistribution on a slope and great spatial variance in the thickness of soil humus layer. Changes of humus layer thickness will result in such physical properties variations as soil moisture and soil temperature. And soil moisture and soil temperature are important factors for freeze-thaw erosion, besides they can affect soil particles and chemical elements movement on the surface and soil profile. In order to explore the law of changes of soil moisture and soil temperature by time and depth of soil profile, two field monitoring points A and B were selected to monitor soil moisture and soil temperature simultaneously. At site A, soil humus layer is about 60 cm, and at site B, soil humus layer is about 130 cm. Soil temperature was recorded with a thermistor thermometer at eight o'clock a. m. everyday from 10 April to 14 June and twice a week from 23 January to 7 April. Soil moisture was monitored with an oven after sampling by drills. Soil moisture and temperature were measured at an interval of 10 cm from the surface to 150 cm deep on two profiles in the paper. Results show that the thickness of humus layer has significant influences on soil moisture and soil temperature. The thicker the humus layer is, the slower the rate of thaw. At site A, the rate of thaw was 2.4cm/day, however, it was 2.1cm/day at site B. Furthermore, the freeze time lags a week or so. At the same time, soil moisture of thicker humus layers is more than that of thinner humus layers in black soil region, as well as the moving extent of soil moisture is deeper. The humus layer has a great impact on the distribution of soil moisture on the profile. As a result, runoff rate during a rainstorm will occur differently from place to place because of the diversity in humus layer depth on a slope.

Taking Pingchuan and Liuba oases in the middle reaches of the Heihe River as examples, the spatial diversification of soil moisture content in oasis and ecotone is analysed using methods of combination of field sampling with laboratory analysis. The results show that the level diversification of soil moisture content along the oasis-desert is distinct in nonirrigated areas, the soil moisture content is higher than that of ecotone and desert. The soil moisture content shows a declining trend from the oasis to ecotone and desert, that is, the soil moisture content decreases from 20% in oasis to 2.9% in the oasis-desert ecotone. Firstly, the differences of soil moisture content are mostly influenced by soil characteristics and soil texture, secondly, influenced by microclimate conditions such as level airflow near ground of oasis-desert belts where soil can transport vapor from oasis area to near desert, and thirdly, the oasis soil moisture content likely moves levelly to desert soil. The active layer soil moisture content at soil profile in the oasis shows an increasing trend from surface layer to understratum. In the range of 0~60cm, the trend of soil moisture content increases in evidence from surface layer to understratum, and the change extent is about 3.12%~21.77%. Whereas in the ecotone and desert soil profiles, the soil moisture contents in surface layer and understratum are lower than that in the middle layer of 20~30cm, this is likely related with the formation and movement of condensation water of desert soil. It is proved that there is dry sand bed in 0~20cm that has distinct restrained effect to evaporation in substrate.It is beneficial to soil moisture content maintenance in that layer. It has important ecological meaning for sandy vegetation. Because of over extracting of groundwater in the oasis and obvious impact of human activities in the ecotone, the ecological gap has been formed, constituting a threat to the ecosystem security. The changes of soil moisture content in the oasis-desert ecological ecotone reflect the extents of water utilization of human being.

Flood disaster is still a threat in the lower Yellow River due to unusual precipitation caused by the deposit of channel, the hidden danger in the embankment and unfavorable riverbed in the lower Yellow River. Study on the embankment-break flood characteristics of the lower Yellow River can afford the scientific basis for flood disaster mitigation. According to the characteristics of the embankment-break flood in the Yellow River,flood routing characteristics of embankment-break is simulated at four different locations of the lower Yellow River by inputting terrain data, typical historical flood data and land use data of the study area to two-dimensional unsteady-state flow model. Simulated results show that: Firstly, routing flood encroach the rivers on the way and enter into the rivers after reaching the lower reaches;secondly, in the same river reach, flood submerged area of north band is bigger than the corresponding location of south bank towards the same historical flood;thirdly, it is different in flood submerged degree of different regions due to the different spatial locations of floodplain; and fourthly, the area of mainstream where flood depth is high and flood velocity is quick is relatively small, but the area of non-mainstream where flood depth is low and flood velocity is slow is relatively big. Flood disaster risk in the protected zone of the embankment will be analyzed by using the results of the simulated flood in this paper, on the basis of the simulated results, the spatial pattern of the flood disaster risk in the protected zone will be analyzed in the lower Yellow River in the future. The attempt on the simulated methods and technique of the flood routing can serve as a reference to the researches in other similar regions. In this study, some factors such as the sediment, infiltration and evaporation weren't considered, which is a limitation to research the hydraulic characteristic of the levee-breaking flood in the Yellow River. In the succeeding simulation, the sediment should be considered to research the long-term influence on the local environment of preventing flood due to the deposit of the sediment in the riverway. At the same time the surface features should the whole way be close to the reality.

Based on remote sensing images in three different years (1986, 1994 and 2002), patch-dynamics model is used to simulate the annual land use/cover change (LUCC) from 1986 to 2004 in Yuzixi catchment. Using the modeling results of LUCC, the linear regression model and multivariate nonlinear regression model are employed to analyze the relationship between runoff, rainfall and LUCC at different time scales. The results show that: (1) The correlation coefficients between rainfall and runoff at different time scales are significantly different. The coefficient at monthly scale is the largest, which is 0.807. The coefficient at daily scale is the smallest (0.311). The results also show that, at daily scale, the time lag of rainfall and runoff has to be taken into account. (2) The results of partial correlation analysis show that, at different time scales, LUCC has significant impacts on the relationship between rainfall and runoff. At yearly scale, the impact of rainfall on runoff is larger than that of temperature on runoff, while the results at monthly scale are the reverse. The relationships between runoff and LUCC in Yuzixi catchment at different time scales are also different. Only at monthly scale, the significance of partial correlation analysis is acceptable. (3) At different time scales, the modeling accuracies of multivariate nonlinear regression analysis are higher than that of linear regression analysis. The nonlinear characteristics of different factors at different time scales are different. For example, the nonlinear index of rainfall at monthly scale is the largest (8.3) and the nonlinear index at daily scale is the smallest (0.4) (runoff is the dependent variable). The nonlinear index of temperature is 2.2 at month scale and the nonlinear index is 1.6 at daily scale. The nonlinear index of resident area is 0.725 at monthly scale and the nonlinear index is 1.01 at daily scale.