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1.
Extraction and analysis of the shoreline and land reclamation patterns are important for studies on topics such as the dynamics of coastal wetland ecological environments, transportation and exchange of material energy in coastal regions, and recruitment of fishery resources. Spatial-temporal variations in the shoreline and land reclamation in the Bohai Sea were analyzed based on 49 Landsat images of 7 periods from 1985 to 2015. The following conclusions were drawn.(1) The extracted shoreline data based on visual interpretation had high precision, and the shoreline extraction errors could be controlled within the theoretical range.(2) Over the past 30 years, the shoreline of the Bohai Sea has exhibited an average rate of change of 188.47 m/a and an average accretion distance of 3.55×10~3 m toward the sea. The fastest rate of shoreline change occurred in Laizhou Bay(134.78 m/a), followed by Bohai Bay(128.20 m/a) and Liaodong Bay(61.69 m/a).(3) The average rate of reclamation was 3.25×10~4 ha/a in the Bohai Sea, where the total area of aquaculture land, unused land, and salt land exceeded 60% of the total reclamation area.(4) The geometric shape of the bay became increasingly complicated from year to year, and the geometric center of gravity of the bay moved rapidly toward the sea. In addition, the area of the bay showed a significant decreasing trend. Therefore, to protect the function and structure of the ecosystem in coastal regions, we must control the scale and rate of land reclamation in the future.  相似文献   

2.
The Belt and Road Initiative(BRI)–a development strategy proposed by China – provides unprecedented opportunities for multi-dimensional communication and cooperation across Asia,Africa and Europe.In this study,we analyse the spatio-temporal changes in cultivated land in the BRI countries(64 in total) to better understand the land use status of China along with its periphery for targeting specific collaboration.We apply FAO statistics and Globe Land30(the world's finest land cover data at a 30-m resolution),and develop three indicator groups(namely quantity,conversion,and utilization degree) for the analysis.The results show that cultivated land area in the BRI region increased 3.73×10~4 km~2 between 2000 and 2010.The increased cultivated land was mainly found in Central and Eastern Europe and Southeast Asia,while the decreased cultivated land was mostly concentrated in China.Russia ranks first with an increase of 1.59×10~4 km~2 cultivated land area,followed by Hungary(0.66×10~4 km~2) and India(0.57×10~4 km`2).China decreased 1.95×10~4 km~2 cultivated land area,followed by Bangladesh(–0.22×10~4 km~2) and Thailand(–0.22×10~4 km~2).Cultivated land was mainly transferred to/from forest,grassland,artificial surfaces and bare land,and transfer types in different regions have different characteristics:while large amount of cultivated land in China was converted to artificial surfaces,considerable forest was converted to cultivated land in Southeast Asia.The increase of multi-cropping index dominated the region except the Central and Eastern Europe,while the increase of fragmentation index was prevailing in the region except for a few South Asian countries.Our results indicate that the negative consequence of cultivated land loss in China might be underestimated by the domestic-focused studies,as none of its close neighbours experienced such obvious cultivated land losses.Nevertheless,the increased cultivated land area in Southeast Asia and the extensive cultivated land use in Ukraine and Russia imply that the regional food production would be greatly improved if China' "Go Out policy" would help those countries to intensify their cultivated land use.  相似文献   

3.
河西走廊张掖绿洲土地利用/土地覆盖变化特征   总被引:8,自引:0,他引:8  
Taking two false color composite Landsat 5 TM(Thematic Mapper)images of band 4,3,2taken in 1995 and 2000 as data resources,this paper carried out study on LUCC of Zhanye oasis in recent five years by interpretation according to land resources classification system of 1∶00,000 Resources and Environmental Database of the Chinese Academy of sciences.The results show that great changes have taken place in landuse/landcover in Zhangye oasis since 1995:(1)Changes of landuse structure show that cropland and land for urban construction and built-up area increased,on the contrary,water area and grassland decreased.These changes reflect the deterionration of arrangement of water and land resources between the upper and lower reaches of the Heihe River.(2)Regional differences of landuse/landcover are evident,characterized by following aspects:in Sunan County located in Qilian Mountain area,unused land and grassland decreased,but cropland and land for urban construction and built-up area inreased.In Minle and Shandan counties located in foothills,unused land,warer area and cropland decreased,but grassland and land for urban construction and built-up area increased.In Zhangye City,Linze County and Gaotai County located in plain area of the middle reaches of the Heihe River,unused land,warer area and grassland decreased,while woodland,cropland and land for urban construction and buile-up area increased.  相似文献   

4.
China had implemented the national strategies for Major Function-oriented Zones(MFOZs)to realize the goal of national sustainable development since 2010.This study analyzed and compared spatio-temporal characteristics and differences in built-up area for China’s MFOZs using a China’s Land Use Database(CLUD)derived from high-resolution remotely sensed images in the periods of 2000–2010 and 2010–2013.To sum up:(1)The percentage of built-up area in each of the MFOZs was significantly different,revealing the gradient feature of national land development based on the distribution of the main functions.(2)Annual growth in built-up area in optimal development zones(ODZs)decreased significantly during 2010–2013 compared with the period 2000–2010,while annual growth in built-up area in key development zones(KDZs),agricultural production zones(APZs)and key ecological function zones(KEFZs)increased significantly.(3)In ODZs,the average annual increase in built-up area in the Yangtze River Delta region was significantly higher than in other regions;the average area increase and rate of increase of built-up area in KDZs was faster in the western region than in other regions;average annual area growth of built-up area in APZs in the northeast,central and western regions was twice as high as the previous decade on average;the annual rate of change and increase in the dynamic degree of built-up area were most notable in KEFZs in the central region.(4)The spatial pattern and characteristics of built-up area expansions in the period 2010–2013 reflected the gradient feature of the plan for MFOZs.But the rate of increase locally in built-up area in ODZs,APZs and KEFZs is fast,so the effective measures must be adopted in the implementation of national and regional policies.The conclusions indicated these methods and results were meaningful for future regulation strategies in optimizing national land development in China.  相似文献   

5.
The spatio-temporal pattern of the global water resource has significantly changed with climate change and intensified human activities. The regional economy and ecological environment are highly affected by terrestrial water storage(TWS), especially in arid areas. To investigate the response relationships between TWS and changing environments(climate change and human activities) in Central Asia, we used the Gravity Recovery and Climate Experiment(GRACE) data, Climatic Research Unit(CRU) climate data and Moderate Resolution Imaging Spectroradiometer(MODIS) remote sensing data products(MOD16A2, MOD13A3 and MCD12Q1) from 2003 to 2013, as well as the slope and Pearson correlation analysis methods. Results indicate that:(1) TWS in about 77% of the study area decreased from 2003 to 2013. The total change volume of TWS is about 2915.6 × 108 m~3. The areas of decreased TWS are mainly distributed in the middle of Central Asia, while the areas of increased TWS are concentrated in the middle-altitude regions of the Kazakhstan hills and Tarim Basin.(2) TWS in about 5.91% of areas, mainly distributed in the mountain and piedmont zones, is significantly positively correlated with precipitation, while only 3.78% of areas show significant correlation between TWS and temperature. If the response time was delayed by three months, there would be a very good correlation between temperature and TWS.(3) There is a significantly positive relationship between TWS and Normalized Difference Vegetation Index(NDVI) in 13.35% of the study area.(4) The area of significantly positive correlation between TWS and evapotranspiration is about 31.87%, mainly situated in mountainous areas and northwestern Kazakhstan. The reduction of regional TWS is related to precipitation more than evaporation. Increasing farmland area may explain why some areas show increasing precipitation and decreasing evapotranspiration.(5) The influences of land use on TWS are still not very clear. This study could provide scientific data useful for the estimation of changes in TWS with climate change and human activities.  相似文献   

6.
Rubber plantation is the major land use type in Southeast Asia. Monitoring the spa- tial-temporal pattern of rubber plantation is significant for regional land resource development, eco-environmental protection, and maintaining border security. With remote sensing tech- nologies, we analyzed the rubber distribution pattern and spatial-temporal dynamic; with GIS and a newly proposed index of Planted Intensity (PI), we further quantified the impacts and limits of topographical factors on rubber plantation in the border region of China, Laos and Myanmar (BRCLM) between 1980 and 2010. The results showed that: (1) As the dominant land use type in this border region, the acreage of rubber plantation was 6014 km2 in 2010, accounting for 8.17% of the total area. Viewing from the rubber plantation structure, the ratio of mature- (〉10 year) and young rubber plantation (〈 10 year) was 5:7. (2) From 1980 to 2010, rubber plantation expanded significantly in BRCLM, from 705 km2 to 6014 km2, nearly nine times. The distribution characteristics of rubber plantation varied from concentrated toward dispersed, from border inside to outside, and expanded further in all directions with Jinghong City as the center. (3) Restricted by the topographical factors, more than 4/5 proportion of rubber plantation concentrated in the appropriate elevation gradients between 600 and 1000 m, rarely occurred in elevations beyond 1200 m in BRCLM. Nearly 2/3 of rubber plantation concentrated on slopes of 8~-25~, rarely distributed on slopes above 35~. Rubber plantation was primarily distributed in south and east aspects, relatively few in north and west aspects. Rubber planted intensity displayed the similar distribution trend. (4) Comparative studies of rubber plantation in different countries showed that there was a remarkable increase in area at higher elevations and steeper slopes in China, while there were large appropriate topog- raphical gradients for rubber plantation in Laos and Myanmar which benefited China for rubber trans-boundary expansion. (5) Rubber plantation in BRCLM will definitely expend cross borders of China to the territories of Laos and Myanmar, and the continuous expansion in the border region of China will be inevitable.  相似文献   

7.
Based on the acquaintance of the regional background of urban-rural transformational development and investigations on the spot,this paper discusses the holistic situation, dominant factors and mechanism of arable land loss and land for construction occupation in the coastal area of China over the last decade,with the aid of GIS technology.Conclusions of the research are summarized as follows:(1)the arable land had been continuously decreasing from 1996 to 2005,with a loss of 1,708,700 hm^2 and an average decrement of 170,900 hm^2 per year;(2)land for construction increased 1,373,700 hm^2 ,with an average increment of 153,200 hm^2 per year;(3)total area of encroachment on arable land for construction between 1996 and 2005 was 1,053,100 hm^2 ,accounting for 34.03%of the arable land loss in the same period,the percentages of which used for industrial land(INL),transportation land(TRL),rural construction land(RUL)and town construction land(TOL)are 45.03%,15.8%,15.47%and 11.5%,respectively;and(4)the fluctuation of the increase of construction land and encroachment on arable land in the area were deeply influenced by the nation's macroscopic land-use policies and development level of regional economy.The growth of population and advancement of technology promoted the rapid industrialization, construction of transportation infrastructures,rural urbanization and expansion of rural settlements in the eastern coastal area,and therefore were the primary driving forces of land-use conversion.  相似文献   

8.
Aridity index reflects the exchanges of energy and water between the land surface and the atmosphere, and its variation can be used to forecast drought and flood patterns, which makes it of great significance for agricultural production. The ratio of potential evapotranspiration and precipitation is applied to analyse the spatial and temporal distributions of the aridity index in the Belt and Road region under the 1.5℃ and 2.0℃ global warming scenarios on the basis of outputs from four downscaled global climate models. The results show that:(1) Under the 1.5℃ warming scenario, the area-averaged aridity index will be similar to that in 1986–2005(around 1.58), but the changes vary spatially. The aridity index will increase by more than 5% in Central-Eastern Europe, north of West Asia, the monsoon region of East Asia and northwest of Southeast Asia, while it is projected to decrease obviously in the southeast of West Asia. Regarding the seasonal scale, spring and winter will be more arid in South Asia, and the monsoon region of East Asia will be slightly drier in summer compared with the reference period. While, West Asia will be wetter in all seasons, except winter.(2) Relative to 1986–2005, both areal averaged annual potential evapotranspiration and precipitation are projected to increase, and the spatial variation of aridity index will become more obvious as well at the 2.0℃ warming level. Although the aridity index over the entire region will be maintained at approximately 1.57 as that in 1.5℃, the index in Central-Eastern Europe, north of West Asia and Central Asia will grow rapidly at a rate of more than 20%, while that in West Siberia, northwest of China, the southern part of South Asia and West Asia will show a declining trend. At the seasonal scale, the increase of the aridity index in Central-Eastern Europe, Central Asia, West Asia, South Asia and the northern part of Siberia in winter will be obvious, and the monsoon region in East Asia will be drier in both summer and autumn.(3) Under the scenario of an additional 0.5℃ increase in global temperature from 1.5℃ to 2.0℃, the aridity index will increase significantly in Central Asia and north of West Asia but decrease in Southeast Asia and Central Siberia. Seasonally, the aridity index in the Belt and Road region will slightly increase in all other seasons except spring. Central Asia will become drier annually at a rate of more than 20%. The aridity index in South Asia will increase in spring and winter, and that in East Asia will increase in autumn and winter.(4) To changes of the aridity index, the attribution of precipitation and potential evapotranspiration will vary regionally. Precipitation will be the major influencing factor over southern West Asia, southern South Asia, Central-Eastern Siberia, the non-monsoon region of East Asia and the border between West Asia and Central Asia, while potential evapotranspiration will exert greater effects over Central-Eastern Europe, West Siberia, Central Asia and the monsoon region of East Asia.  相似文献   

9.
21世纪初中国土地利用变化的空间格局与驱动力   总被引:33,自引:15,他引:18  
Land use and land cover change as the core of coupled human-environment systems has become a potential field of land change science (LCS) in the study of global environmental change. Based on remotely sensed data of land use change with a spatial resolution of 1 km × 1 km on national scale among every 5 years, this paper designed a new dynamic regionalization according to the comprehensive characteristics of land use change including regional differentiation, physical, economic, and macro-policy factors as well. Spatial pattern of land use change and its driving forces were investigated in China in the early 21st century. To sum up, land use change pattern of this period was characterized by rapid changes in the whole country. Over the agricultural zones, e.g., Huang-Huai-Hai Plain, the southeast coastal areas and Sichuan Basin, a great proportion of fine arable land were engrossed owing to considerable expansion of the built-up and residential areas, resulting in decrease of paddy land area in southern China. The development of oasis agriculture in Northwest China and the reclamation in Northeast China led to a slight increase in arable land area in northern China. Due to the "Grain for Green" policy, forest area was significantly increased in the middle and western developing regions, where the vegetation coverage was substantially enlarged, likewise. This paper argued the main driving forces as the implementation of the strategy on land use and regional development, such as policies of "Western Development", "Revitalization of Northeast", coupled with rapidly economic development during this period.  相似文献   

10.
The agricultural and land policies in China are always focused on protecting its food supply and security because of the country’s large population and improved diets.The crop production guide ’Take Grain as the Key Link’ prompted peasants to plant grain on most of the agricultural land,leading to the majority of fertilizer being used in grain crops for many years in China.This situation has changed dramatically in recent years.Based on data pertaining to provincial crops sown area and fertilizer use per unit area in 1998 and 2008,the temporal and spatial variations of China’s fertilizer consumption by crops were analyzed at the provincial level,and the results are presented here.(1) Fertilizer consumption in China grew strongly in the last decade,while the growth was mainly attributable to the increase of fertilizer con-sumption by horticultural crops.The fertilizer consumption of grain crops dropped from 71.0% in 1998 to 57.8% in 2008.Thus,it is concluded that the emphasis of fertilizer consumption is shifting toward horticultural crops.(2) There were marked differences in the growth rates of fertilizer consumption from the regional point of view.The national average growth rate of fertilizer consumption was 31.9% during 1998-2008.The western and northeastern parts of the country came close to the national average,while the eastern part was lower,with an average of 13.0%,and central China was much higher(50.8%).The increase of fertilizer consumption in central and west China was higher than the other zones,which already ac-counted for 77.9% of the national total.Thus,it is concluded that the consumption emphasis of chemical fertilizer shifts toward the central and western regions.(3) The decline of fertilizer consumption by grain crops was largely due to the decrease in sown area compared with the increase by vegetable crops attributable to the enlarging sown area;the increase by orchard crops was affected by both expanding the sown area and fertilizer use per unit area.  相似文献   

11.
中国耕地和农村宅基地利用转型耦合特征与机制(英文)   总被引:16,自引:5,他引:11  
Land use transition refers to the changes in land use morphology (both dominant morphology and recessive morphology) of a certain region over a certain period of time driven by socio-economic change and innovation, and it usually corresponds to the transition of socio-economic development phase. In China, farmland and rural housing land are the two major sources of land use transition. This paper analyzes the spatio-temporal coupling characteristics of farmland and rural housing land transition in China, using high-resolution Landsat TM (Thematic Mapper) data in 2000 and 2008, and the data from the Ministry of Land and Resources of China. The outcomes indicated that: (1) during 2000-2008, the cor-relation coefficient of farmland vs. rural housing land change is -0.921, and it shows that the change pattern of farmland and rural housing land is uncoordinated; (2) the result of Spear-man rank correlation analysis shows that rural housing land change has played a major role in the mutual transformation of farmland and rural housing land; and (3) it shows a high-degree spatial coupling between farmland and rural housing land change in southeast China during 2000-2008. In general, farmland and rural housing land transition in China is driven by socio-economic, bio-physical and managerial three-dimensional driving factors through the interactions among rural population, farmland and rural housing land. However, the spatio-temporal coupling phenomenon and mechanism of farmland and rural housing land transition in China are largely due to the "dual-track" structure of rural-urban develop-ment.  相似文献   

12.
Reconstructing historical land use and land cover change(LUCC) at the regional scale is an important component of global environmental change studies and of improving global historical land use datasets. By analyzing data in historical documents, including military-oriented cropland(hereafter M-cropland) area, the number of households engaged in M-cropland(hereafter M-household) reclamation, cropland area, and the number of households, we propose a conversion relationship between M-cropland area and cropland area reclaimed by each household. A provincial cropland area estimation method for the Yuan Dynasty is described and used to reconstruct the provincial cropland area for AD1290. Major findings are as follows.(1) Both the M-cropland and cropland areas of each household were high in the north and low in the south during the Yuan Dynasty, which resulted from different natural conditions and planting practices. Based on this observation, the government-allocated M-cropland reclamation area to each household was based on the cropland area reclaimed by each household.(2) The conversion relationship between M-cropland and cropland areas per household showed conversion coefficients of 1.23 and 0.65 for the south and north, respectively.(3) The cropland area in the entire study area in AD1290 was 535.4×106 mu(Chinese area unit, 1 mu=666.7 m~2), 57.8% in the north and 42.2% in the south. The fractional cropland areas for the entire study area, north, and south were 6.8%, 6.6%, and 7.1%, respectively and the per capita cropland areas for the whole study area, north, and south were 6.7, 15.6, and 4.1 mu, respectively.(4) Cropland was mainly distributed in the middle and lower reaches of the Yellow River(including the Fuli area), Huaihe River Basin(including Henan Province), and middle and lower reaches of the Yangtze River(including Jiangzhe, Jiangxi, and Huguang provinces).  相似文献   

13.
榆林地区景观变化探测模型   总被引:3,自引:1,他引:2  
Landscape is a dynamic phenomenon that almost continuously changes. The overall change of a landscape is the result of complex and interacting natural and spontaneous processes and planned actions by man. However, numerous activities by a large number of individuals are not concerted and contribute to the autonomous evolution of the landscape in a similar way as natural processes do. There is a well-established need to detect land use and ecological change so that appropriate policies for the ;egional sustainable development can be developed. Landscape change detection is considered to be effectively repeated surveillance and needs especially strict protocols to identify landscape change. This paper developed a series of technical frameworks on landscape detection based on Landsat Thematic Mapper (TM) Data. Through human-machine interactive interpretation, the interpretation precision was 92.00% in 1986 and 89.73% in 2000. Based on the interpretation results of TM images and taking Yulin prefecture as a case study area, the area of main landscape types was summarized respectively in 1986 and 2000. The landscape pattern changes in Yulin could be divided into ten types.  相似文献   

14.
In a mountainous region, the glacier area and length extracted form the satellite imagery data is the projected area and length of the land surface, which can’t be representative of the reality; there are always some errors. In this paper, the methods of calculating glacier area and length calculation were put forward based on satellite imagery data and a digital elevation model (DEM). The pure pixels and the mixed pixels were extracted based on the linear spectral un-mixing approach, the slop of the pixels was calculated based on the DEM, then the area calculation method was presented. The projection length was obtained from the satellite imagery data, and the elevation differences was calculated from the DEM. The length calculation method was presented based on the Pythagorean theorem. For a glacier in the study area of western Qilian Mountain, northwestern China, the projected area and length were 140.93 km2 and 30.82 km, respectively. This compares with the results calculated by the methods in this paper, which were 155.16 km2 and 32.11 km respectively, a relative error of the projected area and length extracted from the LandSat Thematic Mapper (TM) image directly reach to -9.2 percent and -4.0 percent, respectively. The calculation method is more in accord with the practicality and can provide reference for some other object’s area and length monitoring in a mountainous region.  相似文献   

15.
Earth is always changing.Knowledge about where changes happened is the first step for us to understand how these changes affect our lives.In this paper,we use a long-term leaf area index data(LAI) to identify where changes happened and where has experienced the strongest change around the globe during 1981-2006.Results show that,over the past 26 years,LAI has generally increased at a rate of 0.0013 per year around the globe.The strongest increasing trend is around 0.0032 per year in the middle and northern high latitudes(north of 30°N).LAI has prominently increased in Europe,Siberia,Indian Peninsula,America and south Canada,South region of Sahara,southwest corner of Australia and Kgalagadi Basin;while noticeably decreased in Southeast Asia,southeastern China,central Africa,central and southern South America and arctic areas in North America.  相似文献   

16.
Land expansion of mountain cities in China is not systematically studied yet.This study identified 55 major mountain cities at and above prefecture level,and analyzed the land expansion characteristics and driving forces,based on visually interpreted data from TM images in 1990,2000,2010 and 2015.From 1990 to 2015,total built-up land area of the mountain cities increased by 3.87 times,5.56%per year.The urban land growth was apparently accelerated after 2000,from 4.35%per year during 1990–2000 increased to 6.47%during 2000–2010 and 6.2%during 2010–2015.Compared to the urban population growth,the urban land expansion rate was 44% higher.As a result,the urban land area per capita increased,but it was still within the government control target,and also was much lower than the average of all cities in China.Urban development policy,changes to administrative divisions,GDP and population growth,and road construction were identified as the major driving forces of land expansion.Terrain conditions were not found a relevance to the urban land expansion rate during 1990–2015,but had a significant impact on the layout and shape,and also probably on the urban land efficiency.  相似文献   

17.
This paper uses data for the period 1950–2050 compiled by the United Nations Population Division together with methods including spatial autocorrelation analysis, hierarchical cluster analysis and the standard deviational ellipse, to analyze the spatio-temporal evolution of population and urbanization in the 75 countries located along the routes of the Silk Road Economic Belt and the 21 st-century Maritime Silk Road, to identify future population growth and urbanization hotspots. The results reveal the following: First, in 2015, the majority of Belt and Road countries in Europe, South Asia and Southeast Asia had high population densities, whereas most countries in Central Asia, North Africa and West Asia, as well as Russia and Mongolia, had low population densities; the majority of countries in South Asia, Southeast Asia, Central Asia, West Asia and North Africa had rapid population growth, whereas many countries in Europe had negative population growth; and five Belt and Road countries are in the initial stage of urbanization, 44 countries are in the acceleration stage of urbanization, and 26 are in the terminal stage of urbanization. Second, in the century from 1950 to 2050, the mean center of the study area's population is consistently located in the border region between India and China. Prior to 2000, the trajectory of the mean center was from northwest to southeast, but from 2000 it is on a southward trajectory, as the population of the study area becomes more concentrated. Future population growth hotspots are predicted to be in South Asia, West Asia and Southeast Asia, and hotspot countries for the period 2015–2030 include India, China, Pakistan and Indonesia, though China will move into negative population growth after 2030. Third, the overall urban population of Belt and Road countries increased from 22% in 1950 to 49% in 2015, and it is expected to gradually catch up with the world average, reaching 64% in 2050. The different levels of urbanization in different countries display significant spatial dependency, and in the hundred-year period under con-sideration, this dependency increases before eventually weakening. Fourth, between 2015 and 2030, urban population hotspots will include Thailand, China, Laos and Albania, while Kuwait, Cyprus, Qatar and Estonia will be urban "coldspots." Fifth, there were 293 cities with populations over 1 million located along the Belt and Road in 2015, but that number is expected to increase to 377 by 2030. Of those, 43 will be in China, with many of the others located in India, Indonesia and the eastern Mediterranean.  相似文献   

18.
北京城市蔓延的测度与分析   总被引:5,自引:2,他引:3  
Concerning about the rapid urban growth in recent China, this study takes Beijing as a case and puts forward that urban sprawl can be measured from spatial configuration, urban growth efficiency and external impacts, and then develops a geo-spatial indices system for measuring sprawl, a total of 13 indicators. In order to calculate these indices, different sources data are selected, including land use maps, former land use planning, land price and floor-area-ratio samples, digitized map of the highways and city centers, population and GDP statistical data, etc. Various GIS spatial analysis methods are used to spatialize these indices into 100m×100m cells. Besides, an integrated urban sprawl index is calculated by weight sum of these 13 indices. The application result indicates that geo-spatial indices system can capture most of the typical features and interior differentia of urban sprawl. Construction land in Beijing has kept fast growing with large amount, low efficiency and disordered spatial configuration, indicating a typical sprawling tendency. The following specific sprawl features are identified by each indicator: (1) typical spatial configuration of sprawling: obvious fragmentation and irregularity of landscape due to unsuccessful enforcement of land use planning, unadvisable pattern of typical discontinuous development, strip development and leapfrog development; (2) low efficiency of sprawl: low development density, low population density and economic output in newly developed area; and (3) negative impacts on agriculture, environment and city life. According to the integrated sprawl index, the sprawling amount in the northern part is larger than that in the southern, but the sprawling extent is in converse case; most sprawling area include the marginal area of the near suburbs and the area between highways, etc. Four sprawling patterns are identified: randomly expansion at urban fringe, strip development along or between highways, scattered development of industrial land, leapfrog development of urban residence and industrial area.  相似文献   

19.
Reconstruction of the spatial pattern of regional habitat quality can revivify the ecological environment background at certain historical periods and provide scientific support for revealing the evolution of regional ecological environmental quality.In this study,we selected 10 driving factors of land use changes,including elevation,slope,aspect,GDP,population,temperature,precipitation,river distance,urban distance,and coastline distance,to construct the CA-Markov model parameters and acquired the land use spatial data for 1975,1980,1985,1990,and 1995 by simulation based on the land use status map for 2010.On this basis,we used the InVEST model to reconstruct the spatial pattern of habitat quality in the study area and conducted classification division and statistical analysis on the computed habitat degradation degree index and the habitat quality index.(1)The results showed that from 1975 to 2010,the habitat degradation degree gradually increased,and the habitat degradation grade spatially presented a layered progressive distribution.Habitat quality presented a constantly decreasing trend.The high-value zones were mainly distributed in the mountainous areas,while the low-value zones were mostly located in built-up areas.During the period of 1975-2010,low-value zones gradually expanded to their surrounding high-value zones,and the high-value zones of habitat quality tended to be fragmented.(2)The spatial-temporal variation characteristics of habitat quality from 1975 to 2010 showed that the regions with low habitat quality were difficult to be restored and mostly maintained their original state;the regions with poor habitat quality,which accounted for 6.40%of the total study area,continued to deteriorate,mainly around built-up areas;the regions with good and superior habitat quality,which accounted for 5.68%of the total study area,were easily converted to regions with bad or poor habitat quality,thus leading to the fragmentation of the regional habitat.(3)From 1975 to 2010,land use changes in the study area were significant and had a huge influence on habitat quality;the habitat quality in the study area decreased consistently,and the area of the regions with bad and poor habitat quality accounted for more than 60%of the total study area.Construction land was the largest factor threatening habitat quality.  相似文献   

20.
In this paper, we analyzed the spatial patterns of cultivated land change between 1982 and 2011 using global vector-based land use/land cover data.(1) Our analysis showed that the total global cultivated land area increased by 528.768×104 km~2 with a rate of 7.920×104 km~2/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980 s. Since the 1980 s, the cultivated land area in North America, South America and Oceania increased by 170.854×104 km~2, 107.890×104 km~2, and 186.492×104 km~2, respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769×104 km~2, 4.035×104 km~2 and 86.76×104 km~2, respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236× 104 km~2/a, 2.780×104 km~2/a and 3.758×104 km~2/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of –5.641×104 km~2/a, –0.831×104 km~2/a and –0.595×104 km~2/a, respectively. Moreover, the decreasing trend in Asia was significant.(2) Since the 1980 s, the increase in global cultivated lands was mainly due to converted grasslands and woodlands, which accounted for 53.536% and 26.148% of the total increase, respectively. The increase was found in southern and central Africa, eastern and northern Australia, southeastern South America, central US and Alaska, central Canada, western Russia, northern Finland and northern Mongolia. Among them, Botswana in southern Africa experienced an 80%–90% increase, making it the country with the highest increase worldwide.(3) Since the 1980 s, the total area of cultivated lands converted to other types of land was 1071.946×104 km~2. The reduction was mainly converted to grasslands and woodlands, which accounted for 57.482% and 36.000%, respectively. The reduction occurred mainly in southern Sudan in central Africa, southern and central US, southern Russia, and southern European countries including Bulgaria, Romania, Serbia and Hungary. The greatest reduction occurred in southern Africa with a 60% reduction.(4) The cultivated lands in all the continents analyzed exhibited a trend of expansion to high latitudes. Additionally, most countries displayed an expansion of newly increased cultivated lands and the reduction of the original cultivated lands.  相似文献   

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