检索结果-南通市图书馆

Changes in Climate Factors and Their Impacts on Wind Erosion Climatic Erosivity in Farming-pastoral Zone of Northern China

引用

Chinese Geographical Science 2022年第4期32卷 665-675页

作者： YUE Shuping YAN Yechao ZHANG Shuwen yang jiuchun School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China

Climate change can affect wind erosion power and hence induce changes in wind erosion *** this study,the wind erosion climate factor(C-factor),proposed by the Food and Agriculture Organization of the United Nations,was used to assess the impact of changes in climate on wind erosion climatic *** Mann-Kendall test was employed to detect trends in the C-factor during the period of 1961–2017 in the farming-pastoral zone of northern *** analysis was used to determine the sensitivity of the C-factor to changes in key climate ***,a comparison of the contributions of different climate factors was carried out to understand their impact on changes in the *** results indicated that most of the surveyed region exhibited decreasing trends in wind speed at a confidence level of 90%,while maximum and minimum temperatures showed increasing trends throughout the study *** a consequence of decreasing wind speed,the annual C-factor exhibited significant decreasing trends,with a mean slope of–0.58/*** analysis revealed that in most regions,the changes in the C-factor had significant decreasing trends in spring,winter,and autumn,while in more than two-thirds of the study area,no significant change trends in the C-factor were detected in summer at a confidence level of 90%.Sensitivity analysis showed that the C-factor was most sensitive to wind speed,and that the sensitivity coefficients from July to September were much higher than those in other *** analysis revealed that,for most stations,wind speed(with greater values of sensitivity coefficients)was the dominant factor in the change of C-factor,while for some stations,the minimum temperature made the most contribution to the C-factor’s change due to its dramatic changes during the study *** the minimum temperature sensitivity coefficient was the lowest of all the sensitivity coefficients,it is urgent to evaluate the expected impact of minimum

关键词： climate factors wind erosion climatic erosivity sensitivity analysis dominant factor climate change

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Assessment of High-standard Farmland Construction Effectiveness in Liaoning Province During 2011–2015

引用

Chinese Geographical Science 2019年第4期29卷 667-678页

作者： PU Luoman ZHANG Shuwen yang jiuchun YAN Fengqin CHANG Liping College of Earth Science Jilin University Changchun 130061 China Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun 130102 China Center for Spatial Analysis Department of Microbiology and Plant Biology University of Oklahoma Norman 73019 USA

At present, the large-scale construction of high-standard farmland in China has improved the quality of cropland and crop production and enhanced the eco-environmental security. To obtain a comprehensive understanding of high-standard farmland construction in Liaoning Province of China during the 12 th five-year period(2011–2015), through on-the-spot investigations and remote sensing monitoring, this study assessed the construction effectiveness of ten typical sampling projects in Liaoning Province and then presented practical suggestions. The main conclusions were as follows. 1) The ranges of increase in productivity of the ten sampling projects in Liaoning Province all surpassed the goal of 1500 kg/ha. 2) Among all sampling project areas, the levels of productivity stability of nine sampling projects were higher than that of the surrounding farmland in a severe drought year. However, the productivity stability of the high-standard farmland construction project in Faku County, Yiniupu Town, declined by 1.04% compared with the surrounding farmland. 3) Except for the high-standard farmland construction project in Dengta City, Dengta Irrigation Region, the productivity uniformity of the other nine sampling projects increased by 3.30%–88.10%. 4) Eight of the ten sampling projects belonged to Class 1, and two projects belonged to Class 2, showing that the effectiveness of high-standard farmland construction in Liaoning Province was quite *** were some suggestions for high-standard farmland construction in the future. All departments should strengthen cooperation and formulate corresponding protection and development strategies suitable for local conditions. Additionally, lasting management mechanisms should also be established. Using remote sensing monitoring to assess the high-standard farmland construction effectiveness during the 12 th five-year period could provide experience and decision-making support for high-standard farmland construction in the future.

关键词： high-standard farmland remote sensing monitoring productivity stability productivity uniformity Liaoning Province,China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A MODIS Time Series Data Based Algorithm for Mapping Forest Fire Burned Area

引用

Chinese Geographical Science 2013年第3期23卷 344-352页

作者： yang Wei ZHANG Shuwen TANG Junmei BU Kun yang jiuchun CHANG Liping Northeast Institute of Geography and Agroecology Chinese Academy of Sciences University of Chinese Academy of Sciences Department of Geography and Environmental Systems University of Maryland Baltimore County

Burned area mapping is an essential step in the forest fire research to investigate the relationship between forest fire and cli- mate change and the effect of forest fire on carbon budgets. This study proposed an algorithm to map forest fire burned area using the Moderate-Resolution Imaging Spectroradiameter （MODIS） time series data in Heilongjiang Province, China. The algorithm is divided into two steps： Firstly, the ＇core＇ pixels were extracted to represent the most possible burned pixels based on the comparison of the tem- poral change of Global Environmental Monitoring Index （GEMI）, Burned Area Index （BAI） and MODIS active fire products between pre- and post-fires. Secondly, a 15-km distance was set to extract the entire burned areas near the ＇core＇ pixels as more relaxed conditions were used to identify the fire pixels for reducing the omission error as much as possible. The algorithm comprehensively considered the thermal characteristics and the spectral change between pre- and post-fires, which are represented by the MODIS fire products and the spectral index, respectively. Tahe, Mohe and Huma counties of Heilongjiang Province, China were chosen as the study area for burned area mapping and a time series of burned maps were produced from 2000 to 2011. The results show that the algorithm can extract burned areas more accurately with the hiehest accuracy of 96.61%.

关键词： Burned area mapping Moderate Resolution Imaging Spectroradiameter (MODIS) Global Environmental Monitoring Index(GEMI) Burned Area Index (BAI)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Exploring the tidal effect of urban business district with large-scale human mobility data

引用

Frontiers of Computer Science 2023年第3期17卷 77-90页

作者： Hongting NIU Ying SUN Hengshu ZHU Cong GENG jiuchun yang Hui XIONG Bo LANG School of Computer Science and Engineering Beihang UniversityBeijing 100191China Key Lab of Intelligent Information Processing of Chinese Academy of Sciences(CAS) Institute of Computing TechnologyCASBeijing 100086China Baidu Talent Intelligence Center Baidu Inc.Beijing 100085China Business School Imperial College LondonLondon SW72AZUK Artificial Intelligence Thrust The Hong Kong University of Science and TechnologyGuangzhou 510030China

Business districts are urban areas that have various functions for gathering people,such as work,consumption,leisure and *** to the dynamic nature of business activities,there exists significant tidal effect on the boundary and functionality of business ***,effectively analyzing the tidal patterns of business districts can benefit the economic and social development of a ***,with the implicit and complex nature of business district evolution,it is non-trivial for existing works to support the fine-grained and timely analysis on the tidal effect of business *** this end,we propose a data-driven and multi-dimensional framework for dynamic business district ***,we use the large-scale human trajectory data in urban areas to dynamically detect and forecast the boundary changes of business districts in different time ***,we detect and forecast the functional changes in business *** results on real-world trajectory data clearly demonstrate the effectiveness of our framework on detecting and predicting the boundary and functionality change of business ***,the analysis on practical business districts shows that our method can discover meaningful patterns and provide interesting insights into the dynamics of business *** example,the major functions of business districts will significantly change in different time periods in a day and the rate and magnitude of boundaries varies with the functional distribution of business districts.

关键词： business district trajectory functionality detection tidal effect boundary detection visiting score

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Gully Erosion Regionalization of Black Soil Area in Northeastern China

引用

Chinese Geographical Science 2017年第1期27卷 78-87页

作者： yang jiuchun ZHANG Shuwen CHANG Liping LI Fei LI Tianqi GAO Yan Northeast Institute of Geography and Agroecology Chinese Academy of Sciences College of Earth Science Jilin University College of Environment and Planning Henan University Songliao River Basin Water Conservancy Committee Ministry of Water Resources

Gully erosion is the frequent and main form of soil erosion in the black soil area of the northeastern China, which is one of the most important commodity grain production bases in China. It is encroaching upon the fertile farmland there. Regionalization of gully erosion can reveal the spatial distribution and regularity of the development of gully erosion. Based on the eco-geographical regional background features of the black soil area, this study combined the regionalization with influencing factors of the development of gully erosion. GIS spatial analysis, geostatistical analysis, spatial statistics, reclassification, debris polygon processing and map algebra methods were employed. As a result, the black soil area was divided into 12 subregions. The field survey data on type, length, volume and other characteristics indicators of gully erosion were used to calibrate the results. Then the features of every subregion, such as where the gully erosion is, how serious it is, and why it happens and develops, were expounded. The result is not only an essential prerequisite for gully erosion surveys and monitoring, but also an important basis for gully erosion prevention.

关键词： regionalization gully erosion soil and water conservation black soil area northeastern China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Spatio-temporal Pattern and Spatial Heterogeneity of Ecotones Based on Land Use Types of Southeastern Da Hinggan Mountains in China

引用

Chinese Geographical Science 2015年第2期25卷 184-197页

作者： YU Lingxue ZHANG Shuwen LIU Tingxiang TANG Junmei BU Kun yang jiuchun Northeast Institute of Geography and Agroecology Chinese Academy of Sciences University of Chinese Academy of Sciences Bureau of Land and Resources of Linyi City Department of Geography and Environment Systems University of Maryland Baltimore County

Ecotones have received great attention due to its critical function in energy flux, species harbor, global carbon sequestration, and land-atmosphere interaction. This study investigated land use pattern and spatial heterogeneity of the ecotones among agricultural land, forest land, and grassland of the southeastern Da Hinggan Mountains in the northeastern China. The change of these delineated ecotones under different slopes and aridity conditions was analyzed by two landscape indices, edge density(ED) and core area percentage of landscape(CPL), to explore the inter-linkage between spatial structure of ecotones and socioeconomic development and land management. Specifically, the ecotones such as agriculture-forest(AF) ecotone, forest-grassland(FG) ecotone, and agriculture-forestgrassland(AFG) ecotone moved from the arid southeast to the humid northwest. The flat area with small slope is more edge-fragmented than the steep area since the ED decreases as the slope increases. The AF ecotone mostly found in the humid region is moving to more humid areas while the agriculture-grassland(AG) ecotone mostly found in the dry region is moving towards the drier region.

关键词： ecotones core area percentage of landscape(CPL) edge density(ED) modified moving split window land use pattern spatial heterogeneity

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

China's Wetland Databases Based on Remote Sensing Technology

引用

Chinese Geographical Science 2017年第3期27卷 374-388页

作者： YAN Fengqin LIU Xingtu CHEN Jing YU Lingxue yang Chaobin CHANG Liping yang jiuchun ZHANG Shuwen Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China University of Chinese Academy of Sciences Beijing 100049China International Center for Climate and Global Change Research and School of Forestry and Wildlife Sciences Auburn UniversityAuburn 36849USA College of Earth Science Jilin UniversityChangchun 130061China College of Arts&Sciences Beijing Union UniversityBeijing 100083China

Wetland databases can provide the basic data that necessary for the protection and management of wetlands. A large number of wetland databases have been established in the world as well as in China. In this paper, we review China's wetland databases based on remote sensing(RS) technology after introducing the background theory to the application of RS technology in wetland surveys. A key conclusion is that China's wetland databases are far from sufficient in fulfilling protection and management needs. Our recommendations focus on the use of the hyper-spectral imagery, microwave data, multi-temporal images, and automatic classifications in order to improve the accuracy and efficiency of wetland inventory. Further, attention should also be paid to detect major biophysical features of wetlands and build wetland databases in years after the 1980 s in China. Considering that great gap exists between RS experts and wetland experts, further cooperation between wetland scientists and RS scientists are needed to promote the application of RS in the foundation of wetland databases.

关键词： wetlands inventory remote sensing mapping China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Dynamics of Saline-alkali Land and Its Ecological Regionalization in Western Songnen Plain, China

引用

Chinese Geographical Science 2010年第2期20卷 159-166页

作者： yang jiuchun ZHANG Shuwen LI Ying BU Kun ZHANG Yubo CHANG Liping ZHANG yangzhen Northeast Institute of Geography and Agroecology Chinese Academy of Sciences Changchun 130012 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China Software College Jilin University Changchun 130012 China

As the important reserve land resources for food production,saline-alkali land should play a significant role to ensure the national food security in the context of global food crisis. The western Songnen Plain is one of main distribution regions of saline-alkali land in China,with great potential in agricultural development. In this study,the extent,transformation,spatial distribution and temporal change of saline-alkali land in the western Songnen Plain during 1954–2005 were investigated by using remote sensing and GIS spatial analysis methods. Saline-alkali land change was detected from a temporal series of topographic maps in 1954,satellite images of Landsat MSS in 1976,Landsat TM/ETM in 1988,2000 and 2005 through artificial visual interpretation. The results indicated a significant expansion in saline-alkali land area and aggravation in salinization. The area of saline-alkali land had increased from 401.48×103 ha in 1954 to 1 097.45×103 ha in 2005. While the ratio of light,moderate and serious salinized land areas changed from 6.72︰2.92︰1.00 to 1.25︰1.06︰1.00 in the study period. Grassland,cropland,swampland and water body were the major land use and land cover types from which saline-alkali land transformed. And the secondary salinization occured mainly in Da′an City,Tongyu County,Changling County,Daqing City,Dorbod Mongolian Autonomous County and Zhaoyuan County. Finally,seven large ecoregions and 14 corresponding sub-ecoregions were delineated out based on spatio-temopral dynamic characteristics of saline-alkali land and geo-relational environmental attributes. According to the results,measures of amelioration and ways of development of saline-alkali land in the western Songnen Plain were put forward.

关键词： saline-alkali land salinization ecological regionalization food security Songnen Plain

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Remote Sensing Monitoring of Gullies on a Regional Scale: A Case Study of Kebai Region in Heilongjiang Province, China

引用

Chinese Geographical Science 2015年第5期25卷 602-611页

作者： ZHANG Shuwen LI Fei LI Tianqi yang jiuchun BU Kun CHANG Liping WANG Wenjuan YAN Yechao Northeast Institute of Geography and Agroecology Chinese Academy of Sciences College of Earth Science Jilin University Henan University

Gully erosion is one of the major causes of land degradation in most areas and attracts increasing attention from researchers. We monitored gullies in the Kebai region in Heilongjiang Province of China by using remote sensing data and found that gully density increased with the increase in slope when the slope was less than 3°. Gully density in sunny slopes or windward slopes was greater than in shady slopes or leeward slopes because of the impacts of freezing and thawing, wind and solar radiation. Specifically, the gully density in northeast slope was the greatest and in southwest was the smallest. Gully density was reduced with increasing slope length and the longer the slope length, the less the gully density changed between 1965 and 2005. Affected by runoff, gullies most easily to occur in concave slopes and the critical elevation for gully erosion was 250–275 m. Moreover, hilly regions had the greatest gully density, followed by tableland regions, whereas the gully density in flatlands was the lowest. However, the gully density of these three types of landforms all increased between 1945 and 2000, and the portion of increase was 57.45%(hill), 52.91%(mesa) and 25.32%(plain), respectively.

关键词： gully density gully erosion monitoring remote sensing Kebai region, China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Integrating geographical data and phenological characteristics derived from MODIS data for improving land cover mapping

引用

Journal of Geographical Sciences 2011年第4期21卷 705-718页

作者： CAI Hongyan ZHANG Shuwen BU Kun yang jiuchun CHANG Liping Northeast Institute of Geography and Agroecology CAS Changchun 130012 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

The study developed a feasible method for large-area land cover mapping with combination of geographical data and phenological characteristics, taking Northeast China （NEC） as the study area. First, with the monthly average of precipitation and temperature datasets, the spatial clustering method was used to divide the NEC into four ecoclimate regions. For each ecoclimate region, geographical variables （annual mean precipitation and temperature, elevation, slope and aspect） were combined with phenological variables derived from the moderate resolution imaging spectroradiometer （MODIS） data （enhanced vegetation index （EVI） and land surface water index （LSWI））, which were taken as input variables of land cover classification. Decision Tree （DT） classifiers were then performed to produce land cover maps for each region. Finally, four resultant land cover maps were mosaicked for the entire NEC （NEC_MODIS）, and the land use and land cover data of NEC （NEC_LULC） interpreted from Landsat-TM images was used to evaluate the NEC_MODIS and MODIS land cover product （MODIS_IGBP） in terms of areal and spatial agreement. The results showed that the phenological information derived from EVI and LSWI time series well discriminated land cover classes in NEC, and the overall accuracy was significantly improved by 5.29% with addition of geographical variables. Compared with NEC_LULC for seven aggregation classes, the area errors of NEC_MODIS were much smaller and more stable than that of MODIS_IGBP for most of classes, and the wall-to-wall spatial comparisons at pixel level indicated that NEC_MODIS agreed with NEC_LULC for 71.26% of the NEC, whereas only 62.16% for MODIS_IGBP. The good performance of NEC_MODIS demonstrates that the methodology developed in the study has great potential for timely and detailed land cover mapping in temperate and boreal regions.

关键词： geographical data vegetation phenology MODIS land cover Northeast China

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：