The cities in China are the administrative regions of different scales, and they are actually a kind of the city-region. So, the population size of a city in China can not represent the city’s real urban size. Based the concept of metropolitan area and the urban-rural definition from the 6th National Census, and adopted the related indices of population density and urbanization rate at the same time, the article firstly identified 128 metropolitan areas of China in 2010. Secondly, the article studied the characteristics and change of population size and spatial distribution of metropolitan areas of China. Structurally, the scale of population size in urban China obeys the rank-size rule, while the index of q rose from 0.787 to 0.891 in past 10 years which indicated the concentration of metropolitan system in China; nevertheless, the model of mega metropolitan areas has been seen since 2000, and there remains to be some developing space for those advanced metropolitans. Spatially, most metropolitan areas concentrate in the Eastern China, and three metropolitan interlocking regions have been emerging; the number of metropolitan areas is increasing in Middle China, but the population proportion accounted for the total population of metropolitan areas is lower; the development of metropolitan areas in the Western China lags behind other areas, with a characteristics of polarization. Lastly, the paper put forwards some suggestions.
The spatial pattern of high level concentration on settlement landscape in suburban is the most obvious characteristics of urbanization in the outskirts. The present spatial agglomeration methods for landscape are usually used without selection, and they are also lack of comparability. Therefore, this study proposes 4 different analysis of spatial clustering algorithms in a typical area to describe the agglomeration of settlements. And then a simple application in this typical area which realized by one of the 4 analyses is shown. The results reflect that: 1) The landscape aggregation index (CONTAG) is adapted to distinguishing similar continuous large patches and small fragments which are in different types, and the search radius is relatively limited; nuclear density algorithm is adapted to identifying the macro clustering groups, and it’s not usually used in a small spatial scale; spatial correlation algorithm is suitable for spatially locating the specific elements, and the spatial gradual changes are not seen; Ripley's L function is suitable for recognizing different spatial scales to determine the search radius, but the result is rather a chart than a map; 2) Based on the results of the nuclear density algorithm, three large groups are draw on the settlement landscape in the study area, respectively named "government business center settlement groups" "Feng Wei new settlement group" and "Tourism Resort settlement group", the division mode is consistent with the direction of future development for each economic sector in the study area. Landscape planning itself is a subjective process and may not have the only correct process. Quantification of spatial agglomeration is one of the important ways to study the settlement geography from qualitative methods to quantitative methods. Therefore, calculation results may clearly reflect the rationality of the planning, which is currently in need in the landscape research. The quantitative calculation cannot replace the qualitative description, and the diversity of methods leads to a more perfect planning. It goes without saying that more practicable and objective spatial agglomeration algorithms are looked forward to be applied in the settlement landscape studies.
Based on the spatial properties of the database and the final retained Jiangning District Residential land transfer data from 2004 to 2011, spatial expansion method and geographically weighted regression (GWR) model are applied to simulate the spatial heterogeneity of residential land market in urban district. The influencing factors of residential land price were also tested and analyzed. The results show the following aspects.1)Spatial expansion method and geographically weighted regression (GWR) model can be well applied to simulate spatial heterogeneity of land market in target area. The model could respectively explain 63% of the price changes of residential land and 61% of the price changes of residential land. The interpreting abilities improve significantly than that based on global regression model (47%). Both explanations capacity increased by 16%, 14% and spatial expansion method is slightly better than geographically weighted regression (GWR) model. 2) Spatial expansion method can effectively characterize the spatial structure of the overall trend, which is reflected from the explanatory variables and their interaction term effects on residential land. Geographically weighted regression (GWR) model has advantages in terms of the local parameter estimation. It can make the mode of action of each variable premium visualization by means of GIS. This is a strong rebuttal of the traditional assumptions that hedonic price model has coefficient stability. Overall, the spatial expansion model fits relatively better results. Compared with spatial expansion method, geographically weighted regression (GWR) model can more effectively depict spatial non-stationarity of the influencing factors. In the geographically weighted regression(GWR) model, the order of the average marginal contribution on the land premium from high to low is the distance from water, subway, college and CBD, facility, hospital. Additionally, two variables, the distance from facility and hospital, have the directional difference. 3) The distance from subway, water, university and CBD all have positive effect on marginal residential land price in the entire sample area. They are the key driving factors of residential land price .Each of the affecting patterns has a unique land premium space mode of action. Therefore it can provide scientific basis for segmentation of residential land market in target area. Marginal price effect of waters in residential areas of rapid urbanization is generally greater than industrial areas surrounding. The construction of the subway greatly contributed to construction land expansion of Crisscross and upgrading of residential land price. The construction of University City is also an important strategy for urban development in Urban District, The higher the density of University City, the more significant Its role in promoting residential land price. The marginal price effect of entral business dstrict(CBD) on residential land is progressively decreasing trend from the periphery inward City, but it still has upgrading effect on the surrounding residential land price.
One of the significant contents of the classical geography research is the influence of geographic factor on the social economic development of the city. The lake impact the economic development of surrounding cities through the power of systematic self-organization and human intervention. The urban economic effect region is that the largest geographical range of central urban economic activity impact and promote the development of regional economy, and it represent the relationship between the top city and the other regional cities. The urban economic effect region is a economic region based on the objective economic connection between central city and surrounding region, the spatial organization of it reflects the competition of the city at all levels for the regional economic hinterland. The influence of lake on the temperature, precipitation and soil structure of the surrounding land is called the “Lake effect”. Regard the Bohai as a huge lake and three provinces and two cities of the Bohai rim as the study area, based on the “lake effect” and the BASS model construct the theoretical system, and ensure the hierarchical boundary and circle structure using the buffer analysis and nonlinear regression analysis. The results show that: 1) The influence of lake on the urban economy showed the tendency that decline first and then rise and sharply decline finally with the increase of the distance. 2) The Bohai rim is divided into the core area, the key area and edge area, the line of boundary were 66 km, 216 km and the boundary of the region successively; 3) The characteristics of circle structure was obvious that the central city of the key area and the port city of form the two-core structure; from the core area, the key area to the edge area, the development level of urban economic showed inverse "U" type structure with the increase of the distance. Finally, the advantages and disadvantages of the model are discussed.
The spatial accessibility has been a prerequisite to the linkage and development of regional integration. The relationship between the spatial evolution of metropolitan area and the development of transport network is a kind of spatial interaction. The transport network becomes a material basis and essential prerequisite to the foundation of metropolitan area, and the transport accessibility determines material flow, energy flow and information flow between city and region, and it’s an important gene to the development of metropolitan area. With taking Wuhan metropolitan area as example, this article explores the spatio-temporal evolution of the road network accessibility with the support of space syntax model, GIS technology and statistical analysis method. The basic conclusions are obtained as follows: 1) Pyramid structure shows that the overall level of high-grade road network topology connectivity is relatively low. The above structures and patterns of the road network have a great impact on the transportation system of the city. For instance, some roads with very low accessibility are easy to have traffic jam and low efficiency for distributing traffic flow to the entire road network. 2) Caused by the hierarchy of the road network topology links, the spatial differentiation of urban-rural road network traffic axes is significant, showing a typically composite structure of center-marginal and rank circle, two banded city corridors were formed around the east-west roads along the Yangtze River and the north-south roads along the Beijing-Guangzhou Railway. At the same time, the centrality advantages of Wuhan have been strengthened and a number of different levels orderly integrated “node -spoke” network system were developed. 3) The spatially uneven accessibility pattern of road network has a close relationship with the city and town system, transportation facilities and social-economic development of the area. It should also be noted that there is a complex reciprocal-coordinate relationship between highly developed road networks; the growth of urban-rural road network exhibits a kind of characteristic of cyclical and spiral space evolution, which is resulted from the interaction of two kinds of internal force: expansion and subdivision. Therefore, the metropolitan area should pay more attention on the construction of transport infrastructure, especially those high-grade traffic lines and joints which would have a great impact to the regional accessibility, all these is propitious to the servo and validity of transport network; secondly, the metropolitan area should better have some secondary cities in order to form a multi-polar structure of transport network, it could enhance the balance and stability of total transport network; thirdly, the construction of regional expressway network should been strengthen in order to promote the operation level and efficiency of transport network.
Under the background of tourism developing, Huishang ancient town, a cultural heritage and tourist destination, is experiencing the conflict and integration between local tradition and modern development. Based on documental analysis, the thesis teased out the documents on space production, space identity and the application of them in ancient town research. Applying the method of participant observation, in-depth interview content analysis and tomography of anthropological film, it also made a survey on the production of the physical, social and multi-cultural space in Huishan ancient town as well as analyzed the tendency of the multi-body identity. During the transformation, the physical space of the ancient town tends to be capitalized; social space tends to be a non-community with connection of business and industry relation. The Greater liquidity of it is increasing. The function and association of it tend to be socialized with the main body generalizing. Different culture appears to be mixed and coexists in cultural space. The residents, elites and some tourists show the tendency of humanistic identity and focus on the internal identity formed subjectively. Space developing leaders, developers and some tourists show the tendency of structuralistic identity and focus on observing problems with a perspective of regeneration. They emphasize the process and construction. Study shows the identity tendency that the residents prefer tangible development to intangible increase. This basically reflects that it is remarkable whether the result of tourism development can meet the needs of the residents and be shared with them. Identity is basically culture related. But culture always tends to be rheologic. In order to keep the culture produced open and multiple, make the residents and tourists not be doubted or confused, the independence, inheritance and orientation of production in ancient town should be maintained. Culture balance based on the third space should be constructed actively.
Tourism micro-blogs, an increasingly important tool for tourists to acquire information, also play a pivotal role in promoting tourism marketing for tourist sectors and enterprises, which are of great social and economical values. Compared with traditional tourist websites, tourism micro-blogs can be more informative, interactive and convenient. Therefore, a study of spatial distribution of tourism micro-blogs not only uncovers the spatial distributing law, but also has a profound significance to the betterment of their structure, spatial distribution and on-line tourism information. Recently, however, in academia little attention has been paid to tourism micro-blogs, even there are few qualitative researches in traditional ways, the study has still remained in the infancy. In view of this, the study is to explore the distribution rules and its influencing factors in a perspective of geographic space, with an aim to further study its content and direction, to uncover its spatial distributing rules and to provide a sound basis for the advancement of tourism information and service. By means of using a comprehensive method of Spatial Analysis, Zipf theory, Multiple Regression, the study reveals the influencing factors on the basis of the analysis of its spatial pattern. The results are as follows: Firstly, in China, there are two main tourism micro-blogs: the government tourism micro-blogs in dominance, and the ones on the professional websites as complementation. But beyond all that, the tourism micro-blogs of tourist attractions and tourism associations constitute little proportion and remain to be further strengthened. Secondly, significant regional difference can be shown in spatial distribution of tourism micro-blogs. The density in East China, such as Beijing, Shandong, Shanghai, Jiangsu and Zhejiang, is much larger than that in West China. Moreover, the majority of tourism micro-blogs tends to be distributed in comparatively higher-level cities, and different types of micro-blogs have the same characteristics of centralized concentration. Thirdly, the distribution of tourism micro-blogs obeys to the Zipf principle, showing obvious double fractal structure. The state of development is far from ideal, which falls into two differential levels, and there is still a long way to go for the cause of the disharmony in its degree, scale and structure. Lastly, the spatial distribution of tourism micro-blogs is an integrated effect of population size, informatization degree and tourism resources. Because of the diversity in users and functions, the influencing factors of spatial distribution of different kinds of micro-blogs do have certain difference, and so does the same influencing factor to different kinds of tourism micro-blogs.
Migration in China is not a simple one-step process and usually involves two stages: the initial stage for migrants to leave the place of origin and arrive in the first place of destination, and the subsequent stage for them to move across different cities before their finally settlement. So far most studies have been focused on the first stage and have neglected the subsequent stage, which is nevertheless indispensable for a complete understanding of migration patterns in China. Based on the individual-level event-history data from a random sampling questionnaire survey of 2 977 migrants in Fujian Province in 2009, this article examines patterns and characteristics of migrants’ mobility across cities in the subsequent stage of their migration, using various migration indicators and survival analysis. The article first analyses migrants’ mobility across cities in terms of mobility frequency and intensity, the destination city’s size categories and distance categories, the duration in the first destination cities, the mean residence time in each destination cities, and the temporal distribution of mobility events by their sequence, and then analyzes the time-space paths of the migrants’ mobility across cities from a gender perspective. The results show that migrants’ mobility across cities is a common phenomenon, and its mobility patterns are complex in terms of both migration direction and spatial trajectory. Migrants tend to move to places of longer distance and larger cities with the increase in the number of times of their subsequent migration; but compared to that of the initial stage migration, the distance of the subsequent stage migration is usually shorter. The majority of migrants’ movements across cities occur in the early period of their migration career, and they become less mobile with the increasing duration of their migration. On gender differences, although the mobility frequency of women migrants is lower than men migrants, their mobility intensity is stronger than men migrants. Furthermore, women migrants are more likely to move to large-sized cities than men migrants, and men migrants tend to move in wider spatial ranges and stay in the destination cities for longer periods of time, with no preference in their selection of destination cities between small-sized and large-sized cities. These results suggest that there are some temporal and spatial characteristics of migrant subsequent stage of migration that have not been revealed by conventional research treating migration as a one-step and gender-neutral process, and more efforts are still needed to achieve a better and more complete understanding of them.
From the overall and the partial angles this article values the degree of service industry with added service industry per capita to analyze spatial characteristics of service industry in Northeast China by using the Gene coefficient and Tsui-Wang index. Using the polarization level of added service industry per capita as the dependent variable, and per capita GDP, the added value of the second industry, the actually utilized foreign capital, government expenditure and market development index as the independent variables, this article establishes multiple linear regression model and comprehensively evaluates the driving factors. The results of research are:1) The degree of development of service industry is improved greatly between the year 2000 and 2012 in Northeast China. Difference between them is risen within a narrow range and service industry development pattern is formed with the core in Shenyang, Dalian, Changchun and Harbin. The service industry development is dominated by the geographical location, transportation and resources of these cities. 2) The differences and spatial polarization of service industry development all represent a trend of first increase and then decrease. On the whole, the differences of service industry development are showing the trend of accelerated growth and spatial polarization is showing the trend of diminishing. 3) The role and importance of driving factors is different and per-capita GDP and government finance spending is playing the leading role in the service industry spatial polarization development.
In the context of economic globalization and demographic urbanization, using interaction between regional population and economic development as the main line, the correlated coupling between population system and economic system was studied. Taking 91 counties (cities, districts) of Jiangxi Province as the investigated subject, with the support of GIS and gray relative analysis method (GRA), the model of coupling between population and economy was established by selecting 6 indicators of population system and 5 indicators of economic system. The distinction of coupling development research and coordination development research is shined here. This article associates economic growth stage theory and regional industrial structure evolution theory with coupling, so that the coupling characteristics of population and economic development in Jiangxi Province can be analyzed thoroughly. The following conclusions are found: In spatial sequence, according to the coupling degree and the distribution of economic development level, 91 counties (cities) of Jiangxi Province can be generally divided into four types: harmony (there are 2 districts), amelioration (there are 6 districts), conflict (there are 32 districts) and low-level coupling (there are 51 districts). The features of the coupling type regions are as follows: 1) Low-level coupling. It is the broadest all over the province, concentrated in the southern part of the province. It is mainly in the stage of agricultural economy (the coupling degree of population and economy is very large, and confliction of population and economy is very intense) or the original stage of industrialization (high correlation coupling, population and economic development are both relatively backward). 2) Conflict. It is a large range, mainly in the northern part of Jiangxi Province. And it is roughly in the initial stage of industrialization. Including two cases, one is in the development of counties and cities, and the population structure of employment is lag, constraining economic upgrading of industrial structure. The other one is in a higher degree of industrialization of the city, and the population quality status is a bottleneck of its economic development. 3) Amelioration. Scattered in urban areas, it is in the middle stage of industrialization. The contradiction between population and economy experiences the process of running and adaptation constantly. 4) Harmony. Located in Nanchang and Jiujiang cities, it is in the transitional period of advanced industrialization stage. Its population and economy develop simultaneously, promoting each other. The majority type of the whole province is low-level coupling, supplemented by conflict coupling. The dissertation analyzes characteristics and trends of associated coupling between population change and economic development from the time series. The spatial distribution of coupling degrees conforms to the law of north and south spatial variation. Its spatial distribution appears like "+" shaped, of which the horizontal axis of the concentration of population and economy is Jiangxi section of Zhejiang-Jiangxi railway, the vertical axis is Nanchang-Jiujiang railway, and they intersect in Nanchang. In time series, the sequential changes of the coupling degree between population and economy of Jiangxi Province present significant different phases and undulations, during the transition phase of which gradually from a low level to the stage of amelioration.
China’s urbanization process and urban construction have taken a notable achievement in the past 30 years since the reform and opening-up. At present, the Chinese urbanization has entered a new stage. The urbanization speed is fast in recent years in China, but China’s urbanization level is still lower than the average level of the world, especially the urbanization quality is low. The high-speed urbanization which develops healthily will have to face many severe problems. We must pay attention to construction of healthy urbanization while paying attention to the urbanization speed. This paper presents urbanization coordination development is very important to construction of healthy urbanization. This paper decomposes composite urbanization into four parts, namely population urbanization, economic urbanization, land urbanization and social urbanization. With further consideration, the four parts must be in the coordination coupling state, if not that, composite urbanization will be in an un-health state. The technique for order preference by similarity to ideal solution (TOPSIS) method is applied to evaluate the coordination degree of the four categories of urbanization which is the results of decomposition of comprehensive urbanization. Base on the demographic data at a district level, the article analyzed the coordination development and spatial disparities of urbanization in Henan province in 2012, by a comprehensive application of software Excell and IBM MapInfo 20.0. The result shows that: 1) these cities belonged to high grade coordinated category include Jiyuan, Xinxiang and Jiaozuo. 2) These cities belonged to secondary grade coordinated category include Zhengzhou, Shangqiu, Luoyang, Anyang, but these cities are backward in land urbanization. 3) These cities belonged to primary coordinated category include Hebi and Luohe, but these cities are backward in social urbanization. It may be the cause that is ignored that sufficient supply of public service, when urban develop rapidly. 4) These cities belonged to slight disharmony category include Kaifeng, Nanyang, Pingdingshan, Xuchang, Sanmenxia, these cities’ one part in four parts which namely population urbanization, economic urbanization, land urbanization and social urbanization must be specially excellent or terrible. 5) These cities belonged to medium disharmony category include Zhoukou, Xinyang, Puyang, Zhumadian, these cities’land urbanization obviously developed faster than population urbanization, economic urbanization and social urbanization. Excessive land is employed in city construction, to a large extent land is losed. Based experience of world urbanization development, we judge that urbanization in Henan province is in initial stage of rapid expansion as a whole, urbanization in Henan province will keep to develop rapidly in 20 years. Based anticipation of urbanization fast development in Henan province, and urbanization coordination development situation in every city, the paper analyzes the evaluation results and the spatial disparities of evaluation results to provide the basis for regional urban development policy.
The urban development pattern is an important perspective to understand the matter of regional coordination development, and the comprehensive development of urban economic, society and ecosystem is the important carrier and collective representation of a region’s comprehensive, coordinated and sustainable development. This article chose 16 cities of Hubei Province as study objects, set the 30-years reform and opening as its study period (1984-2013), and constructed an evaluation index system, by which economic production, social life and ecological landscape are included as its subsystems, to calculate the yearly comprehensive development levels of the cities. It used AHP to assign weights for the system’s factors and built measure mode respectively, which includes three dimensions comprised of the growth coefficient, coordination coefficient and comprehensive coefficient. Based on ArcGIS10.0, DPS7.05 and SPSS19, this study used tools such as hierarchical clustering, two-step clustering, ordinal swatches classification, nonlinear mapping analysis, Pearson correlation analysis, Mann-Kendall mutation analysis, global Moran’s I, variation coefficient, Local Moran’s I, and so on, to simulate the analysis of the collective temporal evolution, individual temporal evolution and spatial pattern evolution (whole and part pattern) of urban comprehensive development level (urban clustering, temporal partition and evolution trend ) . The result shows that the comprehensive development levels of most cities have been presenting positive changes and the sub-scale cities were more predominant. The total gap was obvious, while the gaps between two adjacent cities have been gradually converged. The changes in national development concepts, regional strategies and system mechanisms, the urban development basic patterns, the city scale’s dialectical role and the city’s regional features were all have a profound influence in the special-temporal pattern of urban comprehensive development.
Human activities and the environment are greatly affected by climate and weather extremes. A growing interest in extreme climate events is motivated by the vulnerability of our society to the impacts of such events. In the world, the occurrence of flood over the seven big river valleys is of high frequency, and both flood and geological disasters increased due to the increase of intense precipitation events and the consequent increase of their concentration degree. In practice, climate data is inhomogenous meteorological observations series in northern Xinjiang. Climate data is affected by meteorological site migration, meteorological instruments to replace, change the number of observations, urbanization, and so on. In present study, we applied HOMER-HOM methods to detect and adjust the inhomogeneities of daily temperature series. Based on the HOMER-HOM method, we analyzed the inhomogeneities in daily maxima and minimum temperature series at Urumqi station caused by relocations in 1976, 1999 and 2002. Comper of Meta data, we find Urumqi station relocation in 1975 and in 1999, instrument replacement in 2003. It shows that the HOMER-HOM method is a good effect method. The adjusted series exhibited a long-term daily maxima and minimum temperature series for the annual mean series during 1961-2010, in which the daily maxima temperature series bias is high by comparison of correct data and the daily minimum temperature series bias is low by comparison of correct data.
The last deglaciation, transition from the last glacial maximum to the present interglacial (Holocene), has great importance in understanding how Earth’s climate system can abruptly switch from one state to another. This transition was also characterized by several abrupt climatic oscillations, including Heinrich event 1, B?lling-Aller?d, and Younger Dryas. However, uncertainty remains regarding the similarities and differences in monsoon history in different region. Here, we present a high-resolution (10-year on average) monsoonal record covering the time range from 16.82±0.04 to 8.29±0.03 ka BP, Based on 25 high-precision 230Th dates and 740 Oxygen isotopic data from stalagmite SX3-a and SX14 from Sanxing Cave, Northern Guizhou Province, China, an average 10 a resolution Asian Summer Monsoon (ASM) record during the last deglacial was produced. Millennial- to decadal- scale coupling between the ASM and northern high-latitude climate persisted through whole last deglacial period, suggesting that the Atlantic meridional circulation play a role in monsoon climate. Decoupled from decreasing temperatures in Greenland during the BA, the concurrent intensified AM is likely attributed to the increasing insolation and the strong cross-equatorial flow. During the “Preboreal episode”, Antarctic temperature, atmospheric CO2 and CH4 were reached to its maximum values after the abrupt transition of Younger Dryas. Howerver, ASM experienced a 2.7 ka-long gradual increase of the monsoon rainfall. The summer insolation in the North Hemisphere was maximal at around 11,000 a B.P., however, until about 9 000 a B.P. a large remnant ice sheet persisted in North America, which could be impede the rebound of ASM. In addition, the cooling of the Antarctic during the early Holocene maybe also influenced ASM through the strong cross-equatorial flow.
Based on stable carbon isotope (δ13C) signatures and particle size of coastal saline soil of Dongtai, changes in the particle size characteristics and soil organic matter source with different reclamation age were analyzed. Results showed that under the same climate and parent material conditions, soil organic carbon isotope and particle size were mainly affected by reclamation age and human disturbance. Along with the increasing reclamation age, the mean particle size significantly reduced, with DT7 (33.93 μm, forest, with the reclamation age of ~60 a)
Bailongjiang River watershed (BRW), a typical geomorphic area with frequent-hazards, located in the transitional ecotone among the Loess Plateau, Qinba Mountains and Tibet Plateau, was chosen as the study area to analyze the landscape ecological security (LES). Based on the Pressure-State-Response (PSR) conceptual framework and platforms of GIS and RS technology, an evaluation system for landscape ecological security was suggested with three dimensions (Pressure, State and Response) from 1990 to 2010. The three components, namely each of the three dimensions and two factors specific to the particular dimension, were determined separately from each other, and then integrated into a single rating. The factors were also divided into two types, depending on their impact on the ecological security: positive (+) or negative (-). Here the pressure index, which reflected the pressure that geomorphic hazard exerted on the environment, consists of landslides, debris flows, soil and water erosion. The landscape state index, which was related to the quality of the environment, was composed of landscape vulnerability index and ecological service value. The response index, which was described as reaction of human beings to landscape dynamics, was defined as adjusted intensity of natural reserve districts, water area, forest, grazing district and crop lands. And then, the landscape ecological security was classified into 5 levels: low, slight, medium, medium-high and high. In the same time, the evaluation units were Landsat TM pixels and the fundamental data set was obtained by classifying raw TM data in this study; and the factors used in PSR model were obtained by using different data from meteorological station, soil surveys and maps, digitized topographic maps, NDVI, DEM and Landsat TM images. The results showed that: the maximum value of landscape pressure index was 0.697, 0.699, and 0.709 in 1990, 2002 and 2010 respectively, although the average value change was not obvious, which means the landscape pressure increased locally. The values of landscape state index and response index increased from 0.531 and 0.802 in 1990 to 0.550 and 0.815 in 2010, respectively, suggesting that landscape security became more secure. After then, landscape ecological security, which was the weighted sum of the pressure index, the landscape security state index and the response index, increased from 0.623 in 1990 to 0.636 in 2010. In the meantime, the change of LES pattern was small and trended to be better, and the cover area of medium to medium-high grades increased (2 089.95 km2) during the whole period of 1990-2010; especially after 2002, the proportion of above high ecological security levels was up to 52%, showing that the performing of ecological engineering (such as Grain for Green, Construction of Shelter Forest System in the Upper- Middle Changjiang River.) were very effective. As to the spatial distribution pattern, the districts with low ecological security mostly located along the Bailongjiang River and its tributaries, northwestern part of Tanchang County and northern mountains of Diebu County, while the high ecological security happened as nature reserve and forest district. And then, the distribution pattern of LES was opposite to that of landscape ecological risk on the landslides, debris flows, soil and water erosion. This research showed that the PSR model based on gridding GIS was a useful way for the quantitative evaluating and mapping LES under natural hazard stress and can be used in other similar regions.
Land salinization is a land degradation phenomenon which deteriorates the eco-environmental quality and agricultural production security, especially in arid and semi-arid areas. Particularly, the land salinization in Hetao irrigation area of Inner Mongolia (including Hangjinhouqi) is a major problem due to the arid climate, high salinity soil material, high mineralized groundwater, as well as high groundwater level caused by improper irrigation and drainage. Therefore, the monitoring of salinized land distribution is significant to prevent land salinization. Fused images based on different spatial and spectral resolutions are an important approach to improve the accuracy of land salinization classification. In this article, ALOS panchromatic and multi-spectral images of central Hanjinhouqi in Inner Mongolia, China, from August, 2010, were fused by employing the four image fusion methods, i.e., principal component analysis transform (PCA), intensity-hue-saturation transform (IHS), high pass filter (HPF) transform and wavelet transform. The effectiveness of each fusion method was evaluated qualitatively and quantitatively to examine the image quality and classification accuracy of land salinization. The result showed that: 1) spatial resolution of images improved after fused by PCA, IHS and HPF transform. 2) Image fused by HPF fused showed higher streaking noise. 3) Edge information of the object in wavelet transform image lowered compared to other fused image. 4) Spectral distortion of the images fused by PCA and wavelet transform was lesser than ones fused by IHS and HPF. In addition, the analysis of spectral signature showed that the mean gray value of different land cover pixel in the study area has the same change trend in the B2 and B3 bands, while different change trend was observed in B4 band because of the vegetation cover. The highest value of mean gray in the B2 and B3 bands was observed in resident cover, followed in sequence by salinized land, cultivated land, traffic land and water body. The highest value of mean gray in the B4 bands was observed in cultivated land .Furthermore, the land cover and land salinization information of researched area was also studied and extracted based on the interpreting marks, spectral signature and supervised classification. The extracted accuracy of multi-spectral images and fused images were compared as well. The classification results showed that the total classification accuracy and Kappa coefficient of PCA image, wavelet PCA image and wavelet IHS image are higher than multispectral images, while IHS image, HPF image and wavelet single band image are lower. The highest and the lowest value of total classification accuracy and Kappa coefficient were determined in PCA and HPF image respectively. The corresponding highest value of total classification accuracy and Kappa coefficient is 89.60% and 0.879 4 respectively while the corresponding lowest value is 65.20% and 0.654 2, respectively. Specifically, the PCA images had the highest classification accuracy of cultivated land (90.30%)and salinized land(90.90%) and HPF images had the lowest classification accuracy of cultivated land (69.23%)and salinized land(62.72%). The evaluation results of fused image quality and classification accuracy showed that PCA fused images is the best image for land use and land salinization information extraction in the study area.
