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Context-Aware Change Pattern for Code Transformation
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作者 LIU Zhiping 《Wuhan University Journal of Natural Sciences》 CAS CSCD 2018年第4期355-361,共7页
When source code is over-specific to some concrete contexts, developers have to manually change the source code retrieved from the Internet. To solve this problem, we propose the context-aware change pattern(CACP). ... When source code is over-specific to some concrete contexts, developers have to manually change the source code retrieved from the Internet. To solve this problem, we propose the context-aware change pattern(CACP). For a piece of source code, we extract the changes and changes-relevant context from the past code changes, identifying CACP that is the abstract common part of the changes and context. By using CACP, the retrieved source code could be transformed into the suitable one according to different user needs. From the Github we extracted 7 topics, collected 5-6 code snippets per topic and performed 5 different experiments which illustrated that CACP improves code transformation accuracy by 73.84%. 展开更多
关键词 code transformation context-aware change pattern code change
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Surface flux–induced salinity change and its effects on ocean stratification in response to global warming
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作者 Hai Zhi Tianyi Ma +2 位作者 Rong-Hua Zhang Xiaokun Wang Minmin Wu 《Atmospheric and Oceanic Science Letters》 2026年第1期59-65,共7页
Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diver... Global warming induced by increased CO_(2) has caused marked changes in the ocean.Previous estimates of ocean salinity change in response to global warming have considerable ambiguity,largely attributable to the diverse sensitivities of surface fluxes.This study utilizes data from the Flux-Anomaly-Forced Model Intercomparison Project to investigate how ocean salinity responds to perturbations of surface fluxes.The findings indicate the emergence of a sea surface salinity(SSS)dipole pattern predominantly in the North Atlantic and Pacific fresh pools,driven by surface flux perturbations.This results in an intensification of the“salty gets saltier and fresh gets fresher”SSS pattern across the global ocean.The spatial pattern amplification(PA)of SSS under global warming is estimated to be approximately 11.5%,with surface water flux perturbations being the most significant contributor to salinity PA,accounting for 8.1% of the change after 70 years in experiments since pre-industrial control(piControl).Notably,the zonal-depth distribution of salinity in the upper ocean exhibits lighter seawater above the denser water,with bowed isopycnals in the upper 400 m.This stable stratification inhibits vertical mixing of salinity and temperature.In response to the flux perturbations,there is a strong positive feedback due to consequent freshening.It is hypothesized that under global warming,an SSS amplification of 7.2%/℃ and a mixed-layer depth amplification of 12.5%/℃ will occur in the global ocean.It suggests that the salinity effect can exert a more stable ocean to hinder the downward transfer of heat,which provides positive feedback to future global warming. 展开更多
关键词 Sea surface salinity change pattern amplification Upper-ocean stratification Flux-anomaly-forced model intercomparison project
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RS and GIS-based Analysis on Dynamic Changes of Landscape Pattern on Urban-rural Fringe——A Case Study of Licheng District, Jinan City of China 被引量:1
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作者 张芬 吴泉源 +1 位作者 张辉 徐燕慧 《Journal of Landscape Research》 2012年第6期42-46,共5页
By using GIS, RS and landscape ecology, LandsatTM (1993 and 2009) and ETM (2001) remote sensing images of Licheng District of Ji’nan City, Shandong Province were interpreted, and dynamic changes of landscape pattern ... By using GIS, RS and landscape ecology, LandsatTM (1993 and 2009) and ETM (2001) remote sensing images of Licheng District of Ji’nan City, Shandong Province were interpreted, and dynamic changes of landscape pattern in the district were analyzed at the levels of class and landscape. The results showed that during the 16 years the landscape pattern in the district had changed significantly. (a) From the perspective of patch category, areas of arable land, woodland and grassland decreased unceasingly, and arable land accounted for the largest reduction from 488.15 km 2 in 1993 down to 324.37 km 2 in 2009, witnessing a reduction rate of 33.56%. But the patch quantity and fragmentation increased, patch connectivity reduced. Spatial pattern of construction land expanded and its area witnessed a significant increase of 147.05%. Patch cohesion index increased and connectivity grew better. (b) From the perspective of overall landscape, patch quantity, contagion and perimeter-area fractal dimension decreased, patch shape became simple, the Shannon’s diversity index, Shannon’s evenness index and splitting index increased, landscape heterogeneity rose. With the rapid social and economic development, landscape pattern will be more and more influenced by human behaviors 展开更多
关键词 LANDSCAPE pattern Dynamic changeS GIS LICHENG DISTRICT of Ji’nan CITY
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Analysis and Simulation for Landscape Pattern Changes of Land Use in Wuzhong District, Suzhou City 被引量:1
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作者 汪煜 吴国平 何林艳 《Journal of Landscape Research》 2010年第2期39-42,46,共5页
Based on analyzing the changes of land use in Wuzhong District, Suzhou City from 2005 to 2008, temporal and spatial changes of land use from 2008 to 2020 were analyzed by using the model CLUE-S and, from the perspecti... Based on analyzing the changes of land use in Wuzhong District, Suzhou City from 2005 to 2008, temporal and spatial changes of land use from 2008 to 2020 were analyzed by using the model CLUE-S and, from the perspective of landscape ecology, future landscape pattern changes of land use in Wuzhong District were also quantitatively discussed by utilizing landscape indices. The results indicated that there was a large variation range of land use in Wuzhong District from 2005 to 2008 and massive farmland and woodland were transformed into construction land and gardens. Guided by the policy of saving intensive land and protecting farmland, future variation range of land use will get smaller obviously. The fragmentation degree for farmland, woodland and water area will get decreased but will get increased relatively for construction land. In general, all landscapes tend to a balanced development. 展开更多
关键词 changes of land use CLUE-S Landscape pattern
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Study on Coastal Landscape Pattern Change Based on GIS
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作者 赵小娟 王长委 +3 位作者 胡月明 王兵 胡小飞 周建 《Journal of Landscape Research》 2011年第3期39-43,63,共6页
Based on GIS technology,from the perspective of landscape ecology and by taking Dianbai County for example,the paper had made landscape layout division according to land use types and studied dynamic change of local l... Based on GIS technology,from the perspective of landscape ecology and by taking Dianbai County for example,the paper had made landscape layout division according to land use types and studied dynamic change of local land use through indexes' change.The result showed that coastal mudflat in Diantai County had increased obviously while water area had decreased substantially and other lands also decreased in a way from 2005 to 2009.The number of land use patches increased,fractal dimension and isolating degree appeared to be in increasing trend,and diversity and evenness degree presented to be in decreasing trend.Spatial heterogeneity of landscape layout reduced,and dominance and fragmentation degree of it increased.Human activity made larger interference on landscape layout. 展开更多
关键词 LAND USE LANDSCAPE pattern Dynamic change
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The change of Chinese students' cultural patterns and its roots in the process of globalization
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作者 王丽皓 周薇薇 《Sino-US English Teaching》 2011年第2期126-129,共4页
One of the most important characteristics of culture is that it is subject to change. The theory of cultural patterns in intercultural communication is used to study the change of Chinese students' living pattern, co... One of the most important characteristics of culture is that it is subject to change. The theory of cultural patterns in intercultural communication is used to study the change of Chinese students' living pattern, communication pattern and thinking pattern because of globalization. The factors and reasons of both change and the unchanged are analyzed and summarized. 展开更多
关键词 cultural patterns change Chinese students
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Pattern Change and Regional Disparity Tendency of Cultivated Land Use in Jiangsu Province
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作者 金涛 徐舟 《Agricultural Science & Technology》 CAS 2013年第10期1517-1520,1525,共5页
The study has examined the tempo-spatial patterns of cultivated land use change in Jiangsu province. A principal component analysis (PCA) of 18 selected indicators of cultivated land use during the period 1970-2010 ... The study has examined the tempo-spatial patterns of cultivated land use change in Jiangsu province. A principal component analysis (PCA) of 18 selected indicators of cultivated land use during the period 1970-2010 identified 2 main pat- terns of change in planting productivity and economic efficiency. A major shift from production-centered pattern to profit-oriented one occurred in 1984, the time of grain yield surplus and the mitigation of population pressure. In response to the impending Opened Market System, there was a notable tendency of higher efficiency and less productivity since 1997, as well as remarkable regional disparity of cultivated land use change spatially. It revealed a relative decrease in grain cropping share, crop- ping scale and cultivation intensity in South Jiangsu, especially in Tai-Lake region, and the reverse in North Jiangsu. Some suggestions for the future were finally dis- cussed from the above findings. 展开更多
关键词 Cultivated land use pattern change Regional disparity PCA Jiangsu Province
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Spatiotemporal characteristics, patterns, and causes of land-use changes in China since the late 1980s 被引量:304
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作者 LIU Jiyuan KUANG Wenhui +13 位作者 ZHANG Zengxiang XU Xinliang QIN Yuanwei NING Jia ZHOU Wancun ZHANG Shuwen LI Rendong YAN Changzhe WU Shixin SHI Xuezheng JIANG Nan YU Dongsheng PAN Xianzhang CHI Wenfeng 《Journal of Geographical Sciences》 SCIE CSCD 2014年第2期195-210,共16页
Land-use/land-cover changes (LUCCs) have links to both human and nature inter- actions. China's Land-Use/cover Datasets (CLUDs) were updated regularly at 5-year inter- vals from the late 1980s to 2010, with stand... Land-use/land-cover changes (LUCCs) have links to both human and nature inter- actions. China's Land-Use/cover Datasets (CLUDs) were updated regularly at 5-year inter- vals from the late 1980s to 2010, with standard procedures based on Landsat TM/ETM+ im- ages. A land-use dynamic regionalization method was proposed to analyze major land-use conversions. The spatiotemporal characteristics, differences, and causes of land-use changes at a national scale were then examined. The main findings are summarized as fol- lows. Land-use changes (LUCs) across China indicated a significant variation in spatial and temporal characteristics in the last 20 years (1990-2010). The area of cropland change de- creased in the south and increased in the north, but the total area remained almost un- changed. The reclaimed cropland was shifted from the northeast to the northwest. The built-up lands expanded rapidly, were mainly distributed in the east, and gradually spread out to central and western China. Woodland decreased first, and then increased, but desert area was the opposite. Grassland continued decreasing. Different spatial patterns of LUC in China were found between the late 20th century and the early 21st century. The original 13 LUC zones were replaced by 15 units with changes of boundaries in some zones. The main spatial characteristics of these changes included (1) an accelerated expansion of built-up land in the Huang-Huai-Hai region, the southeastern coastal areas, the midstream area of the Yangtze River, and the Sichuan Basin; (2) shifted land reclamation in the north from northeast China and eastern Inner Mongolia to the oasis agricultural areas in northwest China; (3) continuous transformation from rain-fed farmlands in northeast China to paddy fields; and (4) effective- ness of the "Grain for Green" project in the southern agricultural-pastoral ecotones of Inner Mongolia, the Loess Plateau, and southwestern mountainous areas. In the last two decades, although climate change in the north affected the change in cropland, policy regulation and economic driving forces were still the primary causes of LUC across China. During the first decade of the 21st century, the anthropogenic factors that drove variations in land-use pat- terns have shifted the emphasis from one-way land development to both development and conservation. The "dynamic regionalization method" was used to analyze changes in the spatial patterns of zoning boundaries, the internal characteristics of zones, and the growth and decrease of units. The results revealed "the pattern of the change process," namely the process of LUC and regional differences in characteristics at different stages. The growth and decrease of zones during this dynamic LUC zoning, variations in unit boundaries, and the characteristics of change intensities between the former and latter decades were examined. The patterns of alternative transformation between the "pattern" and "process" of land use and the causes for changes in different types and different regions of land use were explored. 展开更多
关键词 satellite remote sensing land-use change CHARACTERISTICS spatial pattern China
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Spatial patterns and driving forces of land use change in China during the early 21st century 被引量:180
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作者 LIU Jiyuan ZHANG Zengxiang +8 位作者 XU Xinliang KUANG Wenhui ZHOU Wancun ZHANG Shuwen LI Rendong YAN Changzhen YU Dongsheng WU Shixin JIANG Nan 《Journal of Geographical Sciences》 SCIE CSCD 2010年第4期483-494,共12页
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 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 21 st 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. 展开更多
关键词 land use change spatial pattern driving forces the early 21st century China
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Integration of InVEST-habitat quality model with landscape pattern indexes to assess mountain plant biodiversity change: A case study of Bailongjiang watershed in Gansu Province 被引量:48
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作者 GONG Jie XIE Yuchu +2 位作者 CAO Erjia Huang Qiuyan LI Hongying 《Journal of Geographical Sciences》 SCIE CSCD 2019年第7期1193-1210,共18页
Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious biodiversity loss with fragile ecological problems. Even thoug... Mountains in western China, hosted rich biodiversity and millions of people and inhabitant with vital ecosystem services, had experienced the most serious biodiversity loss with fragile ecological problems. Even though increasing attentions had been paid to this issue, we still lacked efficient methods to assess the change of plant biodiversity at medium/large scale due to the poor data and co-existing multiple habitat types. This study proposed an integrated method combining InVEST-habitat quality model, NPP and landscape pattern indexes to analyze the spatial heterogeneity of plant biodiversity and its spatiotemporal change on raster cell scale. The results indicated that plant biodiversity service was high in Bailongjiang watershed with obvious spatial pattern variations. The land area containing higher plant biodiversity were 3161 km2, which mainly distributed in the National Nature Reserve and forestry area. While the areas with lower plant biodiversity accounted for 37.67% and mainly distributed in the valleys between Zhouqu-Wudu-Wenxian County, the valley of Minjiang in Tanchang County and alpine mountain snow-covered regions. During 1990–2010, plant biodiversity level tended to increase and the higher plant biodiversity area increased from 14.13% to 17.15% due to ecological restoration and afforestation, while plant biodiversity decreased in the area with intensive human activities, such as cultivated land, urban and rural land. The results showed that combining InVEST-habitat quality model, NPP and landscape pattern indexes can effective reveal mountain plant biodiversity change. The study was useful for plant biodiversity conservation policy-making and human activity management for the disaster-impacted mountainous areas in China. 展开更多
关键词 spatial change HABITAT quality landscape pattern plant BIODIVERSITY conservation: INVEST model Bailongjiang WATERSHED in GANSU Province
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The basic characteristics and spatial patterns of global cultivated land change since the 1980s 被引量:23
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作者 YAO Ziyan ZHANG Lijuan +2 位作者 TANG Shihao LI Xiaxiang HAO Tiantian 《Journal of Geographical Sciences》 SCIE CSCD 2017年第7期771-785,共15页
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 ... 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 528.768×10^4 km^2 with a rate of 7.920×10^4 km^2/a, although this increasing trend was not significant. The global cultivated land increased fastest in the 1980s. Since the 1980s, the cultivated land area in North America, South America and Oceania increased by 170.854×10^4 km^2, 107.890×10^4 km^2, and 186.492×10^4 km^2, respectively. In contrast, that in Asia, Europe and Africa decreased by 23.769×10^4 km^2, 4.035×10^4 km^2 and 86.76×10^4 km^2, respectively. Furthermore, the cultivated land area in North America, South America and Oceania exhibited significant increasing trends of 7.236× 10^4 km^2/a, 2.780×10^4 km^2/a and 3.758×10^4 km^2/a, respectively. On the other hand, that of Asia, Europe and Africa exhibited decreasing trend rates of–5.641×10^4 km^2/a,–0.831×10^4 km^2/a and–0.595×10^4 km^2/a, respectively. Moreover, the decreasing trend in Asia was significant. (2) Since the 1980s, 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 1980s, the total area of cultivated lands converted to other types of land was 1071.946×10^4 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. 展开更多
关键词 cultivated lands characteristics of change spatial pattern GLOBAL 1980s
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Sensitivity of arid/humid patterns in China to future climate change under a high-emissions scenario 被引量:6
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作者 MA Danyang DENG Haoyu +2 位作者 YIN Yunhe WU Shaohong ZHENG Du 《Journal of Geographical Sciences》 SCIE CSCD 2019年第1期29-48,共20页
Changes in regional moisture patterns under the impact of climate change are an important focus for science. Based on the five global climate models (GCMs) participating in the Coupled Model Intercomparison Project Ph... Changes in regional moisture patterns under the impact of climate change are an important focus for science. Based on the five global climate models (GCMs) participating in the Coupled Model Intercomparison Project Phase 5 (CMIP5), this paper projects trends in the area of arid/humid climate regions of China over the next 100 years. It also identifies the regions of arid/humid patterns change and analyzes their temperature sensitivity of responses. Results show that future change will be characterized by a significant contraction in the humid region and an expansion of arid/humid transition zones. In particular, the sub-humid region will expand by 28.69% in the long term (2070-2099) relative to the baseline period (1981-2010). Under 2°C and 4°C warming, the area of the arid/humid transition zones is projected to increase from 10.17% to 13.72% of the total of China. The humid region south of the Huaihe River Basin, which is affected mainly by a future increase in evapotranspiration, will retreat southward and change to a sub-humid region. In general, the sensitivity of responses of arid/humid patterns to climate change in China will intensify with accelerating global warming. 展开更多
关键词 arid/humid patternS CLIMATE change sensitivity ARIDITY index China
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The role of landscape pattern analysis in understanding concepts of land cover change 被引量:5
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作者 Jerry A GRIFFITH 《Journal of Geographical Sciences》 SCIE CSCD 2004年第1期3-17,共15页
Landscape ecology and landscape pattern analysis are important components of national-scale programs to identify trends in land cover change because: 1) Statistics on changes in land cover prop... Landscape ecology and landscape pattern analysis are important components of national-scale programs to identify trends in land cover change because: 1) Statistics on changes in land cover proportions are not spatial. A change matrix derived from GIS provides useful information, but it does not show the spatial form of change in the landscape. Landscape pattern metrics reveal spatial pattern. 2) A growing body of literature has shown that a change in landscape pattern might indicate important changes in ecological functions: forest connectivity and species movements, number and size of farm patches, effects on water quality. Spatial pattern is important in structuring ecological communities and in maintaining existence of competitors. Spatial pattern may be determined by disturbance and may in turn, determine how disturbances propagate through the system. 3) Sometimes landscape pattern may not significantly change, even though land cover proportions do change. Or, vice-versa, sometimes landscape pattern can significantly change, even though land cover proportions don't significantly change. 4) Landscape pattern is an inherent and important part of describing landscapes: based on the literature, one of the most important descriptive characteristics of a landscape is its texture. The objectives of this paper are to: 1) Explain the importance of the role of landscape ecology and landscape pattern analysis in land cover change studies; 2) Review the literature that specifically incorporates landscape ecology into land cover change studies; and 3) List the theoretical and technical issues involved and suggest solutions for them. 展开更多
关键词 landscape pattern landscape monitoring landscape ecology land cover change
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Regional agricultural landscape pattern changes along the Yellow River in Henan Province from 1987 to 2002 被引量:5
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作者 LIANG Guofu DING Shengyan LI Zhiheng 《Journal of Geographical Sciences》 SCIE CSCD 2005年第4期415-422,共8页
Agricultural landscape along the riparian zones is designated as important landscape components for partly controlling water quality, biodiversity, as well as for their aesthetic role in landscapes. Therefore, the cha... Agricultural landscape along the riparian zones is designated as important landscape components for partly controlling water quality, biodiversity, as well as for their aesthetic role in landscapes. Therefore, the change of agricultural landscape along the riparian zones is at the top of the agenda for many policy makers and landscape planners. As a basis for conservation management, sufficient information about landscape structure should be provided. In the present study, we reconstructed the former landscape structure and elucidated the changes in landscape patterns during a period of about 15 years. Two sets of maps were used: a landsat-5 TM image (1987) and landsat-7 ETM image (2002). The frequency index, landscape diversity index and landscape fragmentation index were calculated for analyses. The results showed that: (1) the areas of the irrigated land, river, forest and beach landscape classes presented a decreasing trend while the areas of landscape classes of pool, paddy fields, dry land and construction land increased. (2) Disturbed by human activity, landscape diversity index increased but landscape fragmentation index decreased. In short, Human activities have had important influences on agricultural landscape of the riparian zones along the Yellow River in Henan Province. 展开更多
关键词 agricultural landscape landscape pattern change the Yellow River Henan Province
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STUDY ON THE SPATIAL PATTERNS OF LAND-USE CHANGE AND ANALYSES OF DRIVING FORCES IN NORTHEASTERN CHINA DURING 1990-2000 被引量:11
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作者 LIUJi-yuan DENGXiang-zheng +1 位作者 LIUMing-liang ZHANGShu-wen 《Chinese Geographical Science》 SCIE CSCD 2002年第4期299-308,共10页
Land-use change is an important aspect of global environment change. It is,in a sense, the direct result of human activities influencing our physical environment. Supported bythe dynamic serving system of national res... Land-use change is an important aspect of global environment change. It is,in a sense, the direct result of human activities influencing our physical environment. Supported bythe dynamic serving system of national resources, including both the environment database and GIStechnology, this paper analyzed the land-use change in northeastern China in the past ten years(1990 ― 2000). It divides northeastern China into five land-use zones based on the dynamic degree(DD) of land-use: woodland/grassland ― arable land conversion zone, dry land ― paddy fieldconversion zone, urban expansion zone, interlocked zone of farming and pasturing, and reclamationand abandoned zone. In the past ten years, land-use change of northeastern China can be generalizedas follows: increase of cropland area was obvious, paddy field and dry land increased by 74. 9 and276. 0 thousand ha respectively; urban area expanded rapidly, area of town and rural residenceincreased by 76. 8 thousand ha; area of forest and grassland decreased sharply with the amount of1399. 0 and 1521. 3 thousand ha respectively; area of water body and unused land increased by 148. 4and 513. 9 thousand ha respectively. Besides a comprehensive analysis of the spatial patterns ofland use, this paper also discusses the driving forces in each land-use dynamic zones. The studyshows that some key biophysical factors affect conspicuously the conversion of different land-usetypes. In this paper, the relationships between land-use conversion and DEM, accumulated temperature(≥10℃) and precipitation were analysed and represented. We conclude that the land-use changes innortheast China resulted from the change of macro social and economic factors and local physicalelements. Rapid population growth and management changes, in some sense, can explain the shaping ofwoodland/grassland ― cropland conversion zone. The conversion from dry land to paddy field in thedry land ― paddy field conversion zone, apart from the physical elements change promoting theexpansion of paddy field, results from two reasons: one is that the implementation of market-economyin China has given fanners the right to decide what they plant and how they plant their crops, theother factor is originated partially from the change of dietary habit with the social and economicdevelopment. The conversion from paddy field to dry land is caused primarily by the shortfall ofirrigation water, which in turn is caused by poor water allocation managed by local governments. Theshaping of the reclamation and abandoned zone is partially due to the lack of environmentprotection consciousness among pioneer settlers. The reason for the conversion from grassland tocropland is the relatively higher profits of farming than that of pasturing in the interlocked zoneof farming and pasturing. In northeastern China, the rapid expansion of built-up areas results fromtwo factors: the first is its small number of towns; the second comes from the huge potential forexpansion of existing towns and cities. It is noticeable that urban expansion in the northeasternChina is characterized by gentle topographic relief and low population density. Physiognomy,transportation and economy exert great influences on the urban expansion. 展开更多
关键词 land use land-use change spatial pattern driving force northeasternchina
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Impacts of human activity and natural change on the wetland landscape pattern along the Yellow River in Henan Province 被引量:11
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作者 梁国付 丁圣彦 《Journal of Geographical Sciences》 SCIE CSCD 2004年第3期339-348,共10页
By using GIS and remote sensing techniques, the paper discusses how human activities have changed along the Yellow River in Henan province, China and how these altered activities have influenced the wetland landscape ... By using GIS and remote sensing techniques, the paper discusses how human activities have changed along the Yellow River in Henan province, China and how these altered activities have influenced the wetland landscape pattern change from 1987 to 2002. Results show that the total area of the wetland reduces dramatically compared to 1987, the total area of wetland reduces by 19.18%, the number of the patches in 2002 increases by 21.17%, the density increases by 50%, and the total perimeter increases by 1,290,491 m. Disturbed by human activities, landscape diversity index decreases from 1.1740 in 1987 to 0.9803 in 2002. During the last 20 years, the total area of the rice wetland increases, while the others decrease. Among those, the area of the bulrush wetland decreases most. In 1987, it takes 0.5% of the total area, but in 2002, it only takes 0.11%. The interpenetration of human influences on the wetland natural system has been long and close. The impacts of human activities on the spatial pattern of the wetland landscape along the Yellow River in Henan from 1987 to 2002 are great. 展开更多
关键词 landscape pattern change the Yellow River FLOODPLAIN remote sensing
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Spatial and temporal patterns of the sensitivity of radial growth response by Picea schrenkiana to regional climate change in the Tianshan Mountains 被引量:10
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作者 Zhongtong Peng Yuandong Zhang +6 位作者 Liangjun Zhu Mingming Guo Qingao Lu Kun Xu Hui Shao Qifeng Mo Shirong Liu 《Journal of Forestry Research》 SCIE CAS CSCD 2023年第6期1669-1681,共13页
Climate change significantly impacts forest ecosystems in arid and semi-arid regions.However,spatiotemporal patterns of climate-sensitive changes in individual tree growth under increased climate warming and precipita... Climate change significantly impacts forest ecosystems in arid and semi-arid regions.However,spatiotemporal patterns of climate-sensitive changes in individual tree growth under increased climate warming and precipitation in north-west China is unclear.The dendrochronological method was used to study climate response sensitivity of radial growth of Picea schrenkiana from 158 trees at six sites during 1990-2020.The results show that climate warming and increased precipitation significantly promoted the growth of trees.The response to temperature first increased,then decreased.However,the response to increased precipitation and the self-calibrating Palmer Drought Severity Index(scPDSI)increased significantly.In most areas of the Tianshan Mountains,the proportion of trees under increased precipitation and scPDSI positive response was relatively high.Over time,small-diameter trees were strongly affected by drought stress.It is predicted that under continuous warming and increased precipitation,trees in most areas of the Tianshan Mountains,especially those with small diameters,will be more affected by precipitation. 展开更多
关键词 Regional climate change Picea schrenkiana Climate response sensitivity Spatiotemporal patterns Tianshan mountains
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Numerical simulation of flow focusing pattern and morphological changes in two-phase flow inside nozzle 被引量:2
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作者 Jin Zhao Zhi Ning +1 位作者 Ming Lü Geng Wang 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2019年第1期63-71,共9页
The flow focusing nozzle is a new type of nozzle that performs effective atomization of the discrete phase by means of high-speed motion of the continuous phase.The flow pattern and its morphological changes have a si... The flow focusing nozzle is a new type of nozzle that performs effective atomization of the discrete phase by means of high-speed motion of the continuous phase.The flow pattern and its morphological changes have a significant effect on the atomization, but the influence of different parameters on the morphological change of the flow pattern remains unclear.The flow focusing pattern and morphological changes in the two-phase flow inside the nozzle were simulated numerically, based on the volume of fluid method.The results demonstrate that the ratio of the nozzle-to-capillary distance and capillary diameter, the gas–liquid velocity ratio, and capillary diameter have significant effects on the flow pattern.When the ratio of the nozzle-to-capillary distance H and capillary diameter D increases, or the capillary diameter D increases, the flow pattern tends to transform into a laminar form; however, when the gas–liquid velocity ratio V increases, the flow pattern tends to transform into a turbulence form.Furthermore, we define the cone-shaped expansion rate, cone-shaped focusing rate,and cone angle in order to study the morphological changes in the cone shape inside the nozzle.The results indicate that the morphological change of the cone shape and flow pattern transformation is interrelated.When the cone shape tends to be unstable, the flow pattern changes towards flow blurring, whereas, a stable cone indicates that the flow tends to exhibit a droplet pattern. 展开更多
关键词 Flow FOCUSING pattern TRANSFORMATION MORPHOLOGICAL changes Numerical simulation
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Monitoring periodically national land use changes and analyzing their spatiotemporal patterns in China during 2015–2020 被引量:7
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作者 KUANG Wenhui ZHANG Shuwen +22 位作者 DU Guoming YAN Changzhen WU Shixin LI Rendong LU Dengsheng PAN Tao NING Jing GUO Changqing DONG Jinwei BAO Yuhai CHI Wenfeng DOU Yinyin HOU Yali YIN Zherui CHANG Liping YANG Jiuchun XIE Jiali QIU Juan ZHANG Hansong ZHANG Yubo YANG Shiqi SA Rigai LIU Jiyuan 《Journal of Geographical Sciences》 SCIE CSCD 2022年第9期1705-1723,共19页
High-resolution mapping and monitoring of national land use/cover changes contribute significantly to the knowledge of the interaction between human activities and environmental changes.China’s Land Use/cover Dataset... High-resolution mapping and monitoring of national land use/cover changes contribute significantly to the knowledge of the interaction between human activities and environmental changes.China’s Land Use/cover Dataset(CLUD)for 2020 and its dynamic changes in 2015-2020 were developed to extend the CLUD to over 30 years(i.e.,the 1980s to 2020 at 5-year intervals)by integrating remote sensing big data and knowledge-based human-computer interaction interpretation methods.This integrating method for CLUD 2020 improved the efficiency of national land use/cover mapping and the accuracy of land use pattern change detection compared to earlier CLUD products,with an overall accuracy of 95%.The intensity of land use change decreased across China in 2015-2020 compared to 2010-2015,although both characteristics of its spatial changes were similar.The cropland area continued to shrink at national scale in 2015-2020,with two regional hotspots including the widespread conversions from dry land into paddy land in Northeast China and the coexistence of widespread land cultivation and cropland abandonment in Xinjiang of Northwest China.Built-up land area continued to expand in China,showing consistency between 2015-2020 and 2010-2015,in which hotspots transited from the surroundings of coastal megacities to the city surroundings of the central and western zones.For natural land,although the woodland and grassland decreased in 2015-2020,its magnitude expanded compared to 2010-2015.In comparison,the water body area in Qinghai-Tibet Plateau increased significantly under the continuous impact of climate change.These characteristics of land use change were closely related to the development strategy of the top-level design of the 13th Five-Year Plan(2016-2020)(e.g.,ecological civilization construction and high-quality development). 展开更多
关键词 land use spatial pattern cropland change urban expansion cloud computation remote sensing China
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