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1.
泾河流域土地利用格局的时空变化分析 总被引：6，自引：2，他引：6
本文以泾河流域为例,应用遥感与GIS方法,对该流域1986年、1995年和20∞年3个时期的土地利用变化情况及其特点进行了分析.结果表明:①从1986年至2000年,泾河流域土地利用结构变化不大,均以草地和耕地为主,二者始终占流域总面积的85%以上;其次是林地,占流域总面积的10%左右,其他3种土地利用类型仅占流域总面积的5%左右;②土地利用变化总体来说,林地和草地呈现减少趋势,建设用地和耕地则呈增加趋势;未利用土地和水域面积变化不大;③从1986年至2000年这15年间不同土地利用类型间的相互转化比较复杂,主要发生在林地、草地和耕地三者之间,以草地一耕地转型为最大,达14.87×104hm2.值得注意的是,在草地的亚类间发生的变化,要远大于大类间的相互转化,转化面积均在53×104hm2以上,占草地总面积的1/6,这一变化过程虽然没影响到草地的面积,但却暗示了草地质量先退化后恢复的演变趋势;④政策、城镇扩张和人口增加是造成泾河流域土地利用变化的3个主要原因. 相似文献
2.
以地处北方农牧交错带的西辽河流域为案例区,利用ArcGIS9.2软件平台,对1995年和2005年两期Landsat TM、MSS遥感影像进行目视解译,获取了西辽河流域10年间隔的土地利用,覆被遥感资料,分析了西辽河流域主要土地利用类型的数量及空间转移规律.研究结果显示:①1995年和2005年,西辽河流域土地覆被以草地和耕地为主,二者面积分别占全区的2,5和3,10,10年间土地利用整体特征并未发生重大改变;②西辽河流域绝大部分土地利用变化发生在耕地、草地和未利用土地3个地类,三者的变化绝时值约占全区的93.77%;③10年间北方农牧交错带各种土地类型之间发生了复杂的转移变化,其中草地是变化最剧烈的地类,共有7900.57km~2草地转出和5417.20km~2其它地类转入革地;④政策和人口增长可能是西辽河流域近年来土地利用变化的主要驱动力. 相似文献
3.
北方农牧交错带土地利用/覆被变化分析——以西辽河流域为例 总被引：1，自引：1，他引：0
以地处北方农牧交错带的西辽河流域为案例区,利用ArcGIS9.2软件平台,对1995年和2005年两期L andsat TM、MSS遥感影像进行目视解译,获取了西辽河流域10年间隔的土地利用/覆被遥感资料,分析了西辽河流域主要土地利用类型的数量及空间转移规律。研究结果显示:①1995年和2005年,西辽河流域土地覆被以草地和耕地为主,二者面积分别占全区的2/5和3/10,10年间土地利用整体特征并未发生重大改变;②西辽河流域绝大部分土地利用变化发生在耕地、草地和未利用土地3个地类,三者的变化绝对值约占全区的93.77%;③10年间北方农牧交错带各种土地类型之间发生了复杂的转移变化,其中草地是变化最剧烈的地类,共有7900.57km2草地转出和5417.20km2其它地类转入草地;④政策和人口增长可能是西辽河流域近年来土地利用变化的主要驱动力。 相似文献
4.
鄱阳湖流域土地利用变化的土壤侵蚀效应 总被引：2，自引：0，他引：2
随着鄱阳湖流域开发进程加快,土地利用类型势必发生转移,从而对鄱阳湖流域的生态环境产生影响.为了能反映鄱阳湖流域由于土地利用变化对土壤侵蚀的影响效应,本文通过采用3S技术手段,获取鄱阳湖流域土地利用空间数据与土壤侵蚀数据,引入土地利用变化转移矩阵指数和土壤侵蚀强度指教,对鄱阳湖流域土地利用变化和土壤侵蚀效应空间关系进行定量分析.结果表明:①1985年～2000年间,影响鄱阳湖流域土壤侵蚀强度变化的土地类型主要集中在农田、林地和草地,而水域、工矿居民用地与未利用地三种土地类型对土壤侵蚀强度变化总体变化不大;②加重土壤侵蚀强度的主要是林地转化为农田、林地转化为草地、草地转化为农田;而土地利用类型农田转化为林地、林地内部之间的转化减轻了侵蚀强度.土地利用类型和土壤侵蚀强度之间的定量研究结果反映了土壤侵蚀效应的变化,与鄱阳湖流域的水土流失现实情况一致. 相似文献
5.
在土地利用过程中,影响土地面积变化的驱动力是复杂多样的,文章基于广西左右江流域2001年、2005年、2010年、2015年4期遥感影像,运用目视解译方法对遥感影像进行分析处理,结合GIS空间分析,土地利用动态度模型等方法,对左右江流域土地利用变化情况进行分析。研究结果表明:(1)15年间,在各种用地变化中,耕地的动态度为3.61%、建设用地动态度为13.23%、林地动态度为-1.07%,这三种类型土地的面积变化最为明显。(2)采用主成分分析方法,从经济、人口、农业、土地等4个方面选取13个因子,分析发现社会经济发展、农业发展以及人口增长这三个因素均对左右江流域的土地利用变化产生重要的影响,构成左右江流域土地利用变化的主要驱动力。 相似文献
6.
江苏省土地利用变化及其旅游驱动力研究 总被引：3，自引：3，他引：3
利用江苏省1996年-2008年土地利用变更调查数据,分别从土地利用数量、土地利用结构、土地利用程度三方面分析了江苏省土地利用变化特征,结果表明,近10年来,江苏省耕地、牧草地明显减少,交通用地与居民点及工矿用地迅速增加;土地利用结构信息熵与均衡度总体呈增长态势,用地结构不断趋于均质化;土地利用程度不断增强,用地效率明显提高。结合研究区实际情况,选取旅游总收入作为LUCC变化的旅游驱动因子,借助线性回归分析方法,建立江苏省主要土地利用类型的旅游驱动力模型,结果表明,江苏省旅游经济发展对其土地利用变化具有显著影响。建议制定有关土地利用政策时,应充分考虑影响土地利用变化的旅游驱动力因子,以更好促进区域土地资源的可持续利用。 相似文献
7.
人类活动对泾河流域村落尺度土地利用格局的影响及冲突 总被引：2，自引：1，他引：2
对流域微观尺度土地利用结构变化研究是进行宏观尺度土地资源研究和管理的基础。本文旨在探讨中国西部黄土高原泾河流域村落尺度土地利用的变化及其驱动因素，识别并分析资源利用和管理中存在的冲突与解决方案。研究所用资料来自社区快速评估(RRA)、参与式社区评估(PRA)、农户问卷调查、小组讨论、统计资料等。应用系统抽样法对泾河流域上游的南庄村和史么村的90个农户进行了问卷调查，同时在各村进行PRA研究。主要研究结果有：①通过PRA方法，首次恢复和直观再现了村落尺度1950年代以来主要土地利用类型图及其变化，与1950年代相比，1985年～1995年代中期林地和草地面积呈增加趋势，主要得益于荒山造林。1996年～2004年代草地和林地面积持续增加，耕地面积下降；②1950年代以来，种植作物的种类逐渐转换为市场需求高的经济作物；③不同时期的政策和市场机制的作用是引起这些变化的主要原因；④尝试性地界定和分析了在土地利用管理中的主要冲突类型，即公众认知与意愿的冲突、耕地面积减少与剩余劳动力增加的冲突、生态移民措施与公众愿意的冲突、上游与下游资源利用与保护的冲突。个人因素如教育程度、性别和年龄影响他们对土地结构变化的认知和愿意。研究建议应重视土地利用变化最明显时期的特点，针对冲突及其产生的原因进行研究，提高资源利用效率。 相似文献
8.
北部湾经济区土地利用变化及其驱动力研究 总被引：1，自引：0，他引：1
通过对北部湾经济区1990、2000、2010年的遥感影像图进行监督分类,得出三个年份的土地利用现状图,在此基础上分析了1990-2000年和2000～2010年两个期间内的土地利用结构数量变化、土地利用转移矩阵和土地利用区域变化差异情况,对影响北部湾经济区土地利用变化的驱动力进行分析,得出影响北部湾土地利用变化的主要驱动因素有自然因素驱动力和社会经济因素驱动力两个方面,其中自然因素驱动力包括气候、地形地貌和土壤;社会经济因素驱动力包括经济因素、人口因素、城市化水平、政策因素。 相似文献
9.
黄河三角洲土地利用/覆盖变化驱动力分析 总被引：7，自引：1，他引：7
土地利用/覆盖变化(LUCC)的驱动力分析是土地利用/覆盖变化研究的核心。本文利用黄河三角洲东营市1984年~2001年5个时期的土地利用/覆盖数据,简要分析了黄河三角洲LUCC特征,重点研究其驱动力因子。在黄河三角洲,耕地和未利用地之间的双向转化最为频繁。海陆河流的交互作用使得黄河三角洲淤进蚀退变化占有较大的比重;淡水资源时空上的分布不均匀,使对平原水库的建设力度大为增加。对土地的盲目垦荒和粗放经营方式,是耕地与未利用地双向转换频繁的最主要原因;人口的增长,特别是非农业人口的增长,是居民地增多的主要原因;农业生产效益,对耕地、灌草地、内陆水体和未利用地之间的结构变化产生了较大的影响。在未来几年,整个黄河三角洲的面积将处于一种动态的平衡中,面积基本保持稳定。要实现黄河三角洲的可持续发展,就要在顺应自然因子的条件下,提高水陆比例,科学合理垦殖经营,大力发展和保护灌草地资源。 相似文献
10.
通过小区域、长时段的土地利用变化研究,将土地利用变化情景与土地利用变化过程相结合,以便从微观尺度揭示典型村域的土地利用变化机制。主要采用的研究方法是土地利用制图与农户调查结合,通过数据整理和分析探讨马儿庄村的土地利用变化机制。结果表明:马儿庄村近60年经历了由草地畜牧业为主的土地利用到以农为主、农牧结合土地利用的变化;前50年土地利用引起土地逐步退化,后10年土地迅速恢复。在人口增长和政策驱动下前50年耕地不断增加,1998年以来的扬黄水分和养分输入,使耕地面积下降。在利用过度和使用政策不当的作用下,草地在面积减少的同时质量大幅度下降,2003年禁牧之后迅速恢复。在气候变化和人类活动作用下沙地面积增大,21世纪在退耕还林和退牧还草政策的驱动下,沙地面积大幅减小。近10年土地恢复是扬黄灌区开发的水肥输入、退耕还林和退牧还草政策执行(既有减轻土地压力又有补偿)、生计方式多样化等多种因素作用的结果。马儿庄土地利用变化仍然经受着气候变化、草地利用压力、水浇地土壤盐分变化等挑战。 相似文献
11.
Marjorie Armstrong-Stassen Margaret Landstrom Ramona Lumpkin 《The Information Society》1998,14(2):153-164
This study examined how students who had no prior experience with videoconferencing would react to the use of videoconferencing as an instructional medium. Students enrolled in seven different courses completed a questionnaire at the beginning of the semester and again at the end of the semester. Students at the origination and remote sites did not differ in their reactions toward videoconferencing but there was a significant difference for gender. Women reacted less favorably to videoconferencing. Compared to the beginning of the semester, students reported significantly less positive attitudes toward taking a course through videoconferencing at the end of the semester. There were no significant differences in students' attitudes toward videoconferencing across courses at the beginning of the semester but there were significant differences across the courses at the end of the semester. The results suggest the need for better preparation for both students and instructors. 相似文献
12.
A joint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology his co-workers from Norway US Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells suggesting that China's projected climate warming could decrease the pest's numbers. The study was published in Proceedings of the National Academy of Sciences on September .…… 《中国科学院院刊(英文版)》2008,22(1):6-7
Ajoint study by Prof. ZHANG Zhibin from the CAS Institute of Zoology and his co-workers from Norway, US and Swiss have indicated that historical outbreaks of migratory locusts in China were associated with cold spells, suggesting that China＇s projected climate warming could decrease the pest＇s numbers. The study was published in Proceedings of theNational Academy of Sciences on 17 September, 2007. 相似文献
13.
Caroline Haythornthwaite 《The Information Society》2001,17(3):211-226
A computer-mediated group is a complex entity whose members exchange many types of information via multiple means of communication in pursuit of goals specific to their environment. Over time, they coordinate technical features of media with locally enacted use to achieve a viable working arrangement. To explore this complex interaction, a case study is presented of the social networks of interactions and media use among members of a class of computer-supported distance learners. Results show how group structures associated with project teams dominated who communicated with whom, about what, and via which media over the term, and how media came to occupy their own communication niches: Webboard for diffuse class-wide communication; Internet Relay Chat more to named others but still for general communication across the class; and e-mail primarily for intrateam communication. Face-to-face interaction, occurring only during a short on-campus session, appears to have had a catalytic effect on social and emotional exchanges. Results suggest the need to structure exchanges to balance class-wide sharing of ideas with subgroup interactions that facilitate project completion, and to provide media that support these two modes of interaction. 相似文献
14.
Electronic data interchange (EDI) provides means for interorganizational communication, creates network externalities, requires an advanced information technology (IT) infrastructure, and relies on standards. In the diffusion of such innovations, institutional involvement is imperative. Such institutions contain governmental agencies, national and global standardization organizations, local government, and nonprofit private organizations like industry associations. The last type of organizations we call intermediating institutions. They intermediate or coordinate ("inscribe") the activities of a group of would-be adopters. Unfortunately, little is known of how these organizations shape the EDI diffusion trajectory. In this article we examine one specific type of intermediating organizations?industry associations?and how they advanced the EDI diffusion process in the grocery sectors of Hong Kong, Denmark and Finland. We identify six institutional measures, placed into a matrix formed by the mode of involvement (influence vs. regulation) and the type of diffusion force (supply push vs. demand pull), that can be mobilized to further the EDI diffusion. Industry associations were found to be active users of all these measures to varying degrees. Their role was critical especially in knowledge building, knowledge deployment, and standard setting. Furthermore, institutional involvement varied due to policy and cultural contingencies and power dependencies. 相似文献
15.
Puay Tang 《The Information Society》1998,14(1):19-31
The increasing prospects of digital piracy has prompted the perceived need by electronic publishers to adopt technical systems of protection, and governments to reform their copyright laws. This article is a preliminary study of the management of intellectual property by electronic publishers, defined as those involved in the production of online databases, and CD-ROMs. It focuses on three main issues: (1) how electronic publishers view the increasing threat of piracy; (2) the methods of protection employed to protect intellectual property in digital format; and (3) the importance of technological protection of intellectual property in electronic publications. The analysis is based on a sample of 23 UK electronic publishers. The interviews revealed an interesting assortment of protection methods and did not show that technological protection was a preferred way. Instead, the means of protection, in addition to copyright law, comprised niche markets, pricing, trust, bad publicity, and nontechnical and technical means. 相似文献
16.
Milton Mueller 《The Information Society》2001,17(3):151-163
Long-standing conflict between domain name registrants and trademark holders prompted the Internet Corporation for Assigned Names and Numbers (ICANN) to create a global, mandatory arbitration procedure known as the Uniform Dispute Resolution Policy (UDRP). The UDRP has been used in 2166 cases involving 3938 domain names as of 1 November 2000. The policy gives the initiator of a complaint, generally a trademark holder, the right to choose which ICANN-accredited dispute resolution service provider (RSP) will handle the case. During the preparation of the UDRP,some feared that complainant selection would lead to "forum shopping" that might bias the results. This article performs a statistical assessment of the forum-shopping thesis and finds support for it. There are statistically significant differences in the various RSPs' propensity to take away names from defendants; there are also major differences in the number of cases brought to each RSP. RSPs who take away names have the larger share of cases. The study examines other variables that might explain differences in market share, such as price, the plaintiff's nationality, or the time taken to decide a case. It finds that nationality and time also are correlated with market share. The study concludes that shopping for a favorable outcome is an important factor in the UDRP. 相似文献
17.
Prof. Raymond C.K. Chen a neuropsychologist with the CAS Institute of Psychology has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology.…… 《中国科学院院刊(英文版)》2008,22(1):15-15
Prof. Raymond C.K. Chen, a neuropsychologist with the CAS Institute of Psychology, has made novel progress in his studies of schizophrenia. His work has been reported by a recent issue of Behavioural Neurology. 相似文献
18.
《中国科学院院刊(英文版)》2014,(3)
<正>In Xishuangbanna,one of China’s most biodiverse regions,landscape has changed dramatically during the past three decades due to the conversion of tropical rainforest to rubber plantations.In steep areas,terraces are often constructed before planting rubber trees,which causes two important changes in the soil:the destabilization of soil in the bench terraces and the increased vulnerability of unvegetated riser faces to erosion.Few studies have documented the nature and intensity of erosion on bench terraces.Prof.LIU Wenjie and his colleagues from the Xishuangbanna Tropical Botanical Garden(XTBG)conducted a study in Menglun County(21°5′39″N,101°15′55″E),Xishuangbanna to evaluate the influence 相似文献
19.
Chinese Scientists Use Earth Observation Technologies to Study and Protect Wild Camels 总被引：1，自引：0，他引：1
《中国科学院院刊(英文版)》2014,(3):267-268
<正>Chinese scientists plan to apply Earth Observation technologies to protect the critically endangered wild camels(Camelus ferus).With the help of remote sensing,satellite positioning,geographical information system and wireless sensors networks,they will be able to access the distribution and population of the wild camels and protect their habitats.The project will be carried out by the International Research Center for Wild Camel Conservation,which was jointly established earlier this year by the Institute of Remote Sensing and Digital Earth(RADI)of the Chinese 相似文献
20.
WANG Sijia 《中国科学院院刊(英文版)》2014,(2):192-194
<正>The Paul Gerson Unna Research Group on Dermatogenomics was founded in October 2012 at the Partner Institute for Computational Biology.The ultimate goal of the group is to understand the biology of skin and skin appendages. 相似文献