以Web of Science为数据源,运用文献计量方法与可视化分析工具,从文献时间分布、研究机构、科学领域分布、文献作者和研究热点等维度,对1998-2016年全球土地利用/覆盖变化(LUCC)研究进展进行数据挖掘.研究结果表明:目前LUCC研究日益成熟...以Web of Science为数据源,运用文献计量方法与可视化分析工具,从文献时间分布、研究机构、科学领域分布、文献作者和研究热点等维度,对1998-2016年全球土地利用/覆盖变化(LUCC)研究进展进行数据挖掘.研究结果表明:目前LUCC研究日益成熟,文献逐年稳定增长,发展前景依然广阔;机构和作者合作网络还相对松散,LUCC全球合作有待进一步加强;LUCC研究学科交叉性强,综合集成了环境科学、生态学、地理学等多个自然与社会学科;LUCC研究热点众多,气候变化、生态系统、地表景观、城镇化、森林砍伐等热点受到高度关注;综合性研究是未来LUCC的发展趋势,体现在多学科、多时空、多尺度、多方法的交叉.未来LUCC要在数据标准化、大尺度遥感图像融合、历史地图资料不准确性与当代资料整合,以及LUCC全球分类体系和LUCC成果应用等方面加强研究.展开更多
This study investigated oasis evolution and the changes of peripheral desert in the Sangong River Basin since the 1950 s by rebuilding seven land cover maps derived from black-and-white aerial photographs(1958, 1968,...This study investigated oasis evolution and the changes of peripheral desert in the Sangong River Basin since the 1950 s by rebuilding seven land cover maps derived from black-and-white aerial photographs(1958, 1968, and 1978), a color-infrared aerial photograph(1987), Landsat Thematic Mapper(TM) imagery(1998), Satellite Pour l'Observation de la Terre(SPOT) imagery(2004), and Landsat Operational Land Imager(OLI) imagery(2014). The results showed that:(1) Since 1950, the oasis consecutively expanded more than four times from an alluvial fan to an alluvial plain, causing the shrinkage of desert landscapes that were dominated by a Haloxylon ammodendron Bunge community(HBC) and a Tamarix chinensis Lour community(TLC). Furthermore, the primary(1958–1968) and final(2004– 2014) stages were the most important periods, during which agricultural land experienced the most rapid expansion during the period 1958–1968, and the built-up area showed the most rapid expansion after the 2000 s.(2) Two basic management modes, a "local mode" formed by the local governments and a "farm management mode" developed by Xinjiang Production and Construction Corps, together promoted oasis evolution under various land-use and landcover(LULC) stages.(3) The evolution of the modern oasis during the 1950s–2004 showed the general features of an arid oasis, while during the period of 2004–2014 it was characterized by a large-scale inter-basin water diversion or the import of new water sources.(4) The oasis expanded at the expense of desert vegetation, resulting in distinct variation in the structure of the desert plant community, which will make it more difficult to protect the desert ecosystem.展开更多
In many parts of mainland Southeast Asia rubber plantations are expanding rapidly in areas where the crop was not historically found. Monitoring and mapping the distribution of rubber trees in the region is necessary ...In many parts of mainland Southeast Asia rubber plantations are expanding rapidly in areas where the crop was not historically found. Monitoring and mapping the distribution of rubber trees in the region is necessary for developing a better understanding of the consequences of land-cover and land-use change on carbon and water cycles. In this study, we conducted rubber tree growth mapping in Northeast Thailand using Landsat 5 TM data. A Mahalanobis typicality method was used to identify different age rubber trees. Landsat 5 TM 30 m non-thermal reflective bands, NDVI and tasseled cap transformation components were selected as the model input metrics. The validation was carried out using provincial level agricultural statistical data on the rubber tree growth area. At regional (Northeast Thailand) and provincial scales, the estimates of mature and middle-age rubber stands produced from 30 m Landsat 5 TM data compared well (high statistical significance) with the provincial rubber tree growth statistical data.展开更多
文摘以Web of Science为数据源,运用文献计量方法与可视化分析工具,从文献时间分布、研究机构、科学领域分布、文献作者和研究热点等维度,对1998-2016年全球土地利用/覆盖变化(LUCC)研究进展进行数据挖掘.研究结果表明:目前LUCC研究日益成熟,文献逐年稳定增长,发展前景依然广阔;机构和作者合作网络还相对松散,LUCC全球合作有待进一步加强;LUCC研究学科交叉性强,综合集成了环境科学、生态学、地理学等多个自然与社会学科;LUCC研究热点众多,气候变化、生态系统、地表景观、城镇化、森林砍伐等热点受到高度关注;综合性研究是未来LUCC的发展趋势,体现在多学科、多时空、多尺度、多方法的交叉.未来LUCC要在数据标准化、大尺度遥感图像融合、历史地图资料不准确性与当代资料整合,以及LUCC全球分类体系和LUCC成果应用等方面加强研究.
基金National Natural Science Foundation of China,No.U1303382 The National Basic Research Program of China,No.2014CB460603 The Project of State Key Laboratory of Desert and Oasis Ecology,No.Y471163
文摘This study investigated oasis evolution and the changes of peripheral desert in the Sangong River Basin since the 1950 s by rebuilding seven land cover maps derived from black-and-white aerial photographs(1958, 1968, and 1978), a color-infrared aerial photograph(1987), Landsat Thematic Mapper(TM) imagery(1998), Satellite Pour l'Observation de la Terre(SPOT) imagery(2004), and Landsat Operational Land Imager(OLI) imagery(2014). The results showed that:(1) Since 1950, the oasis consecutively expanded more than four times from an alluvial fan to an alluvial plain, causing the shrinkage of desert landscapes that were dominated by a Haloxylon ammodendron Bunge community(HBC) and a Tamarix chinensis Lour community(TLC). Furthermore, the primary(1958–1968) and final(2004– 2014) stages were the most important periods, during which agricultural land experienced the most rapid expansion during the period 1958–1968, and the built-up area showed the most rapid expansion after the 2000 s.(2) Two basic management modes, a "local mode" formed by the local governments and a "farm management mode" developed by Xinjiang Production and Construction Corps, together promoted oasis evolution under various land-use and landcover(LULC) stages.(3) The evolution of the modern oasis during the 1950s–2004 showed the general features of an arid oasis, while during the period of 2004–2014 it was characterized by a large-scale inter-basin water diversion or the import of new water sources.(4) The oasis expanded at the expense of desert vegetation, resulting in distinct variation in the structure of the desert plant community, which will make it more difficult to protect the desert ecosystem.
文摘In many parts of mainland Southeast Asia rubber plantations are expanding rapidly in areas where the crop was not historically found. Monitoring and mapping the distribution of rubber trees in the region is necessary for developing a better understanding of the consequences of land-cover and land-use change on carbon and water cycles. In this study, we conducted rubber tree growth mapping in Northeast Thailand using Landsat 5 TM data. A Mahalanobis typicality method was used to identify different age rubber trees. Landsat 5 TM 30 m non-thermal reflective bands, NDVI and tasseled cap transformation components were selected as the model input metrics. The validation was carried out using provincial level agricultural statistical data on the rubber tree growth area. At regional (Northeast Thailand) and provincial scales, the estimates of mature and middle-age rubber stands produced from 30 m Landsat 5 TM data compared well (high statistical significance) with the provincial rubber tree growth statistical data.