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1.
《内蒙古科技与经济》2021,(12)
对朝阳市1965年～2020年热岛效应强度进行了分析,结果表明:朝阳市热岛效应的形成始于1990年,20世纪90年代、21世纪初热岛强度呈激增趋势,近10年热岛强度增幅放缓,平均为0.81℃/年;热岛强度存在明显的季节性变化,冬季热岛强度最强,春季最弱;热岛强度也具有明显的日变化特征,日间弱、夜间强,日间甚至出现"冷岛"的现象,且日变化随季节和年份变化也表现出一定特点,冬季热岛强度日变化最为显著,有明显的正值中心和负值中心,近5年日间热岛强度负值时段有一定缩短。 相似文献
2.
北京城市绿地对热岛效应的缓解作用 总被引：1，自引：0，他引：1
按照城市功能定位将北京市分为中心城、卫星城和郊区,利用2005-2011年的19个站点逐日3个时次(8∶00、14∶00、20∶00)的温度数据,对比分析中心城和卫星城城市热岛效应强度及其变化,同时利用野外试验数据,对比研究不同城市绿地对北京城市热岛的缓解作用。结果表明:1各时次年平均气温中心城卫星城郊区,且中心城和卫星城年平均气温波动上升,而郊区却波动下降,致使各时次中心城和卫星城热岛强度波动增强,且热岛强度增幅中心城高于卫星城;2中心城热岛强度冬季夏季,而卫星城夏季冬季,冬季均以8∶00最强,14∶00最弱,夏季卫星城各时次城市热岛强度次序与冬季相同,但夏季中心城却以20∶00最强,14∶00最弱;3绿地缓解热岛效应功能与绿地类型、树种组成、林分密度等群落结构及管理措施等相关,试验绿地夏季9∶00-16∶00的降温幅度约为0.2~12.9℃,各类绿地平均降温幅度介于1.2~9.5℃,平均降温约4.2℃,以乔草绿地最大,草地最低。因此,合理的群落结构与空间布局可增强区域绿地缓解热岛效应功能。 相似文献
3.
典型重工业城市热岛效应特征分析——以唐山市为例 总被引：2，自引：2，他引：0
本文选取唐山这座典型重工业城市,以地震后的气象资料(1977年-2006年)和2006年7月1日-2007年6月30日对比观测资料,采用统计分析方法对热岛效应特征进行研究与对比分析,结果发现:①1977年-2006年间热岛强度平均为0.51℃,最近10年热岛强度平均为0.82℃;②热岛效应的日变化明显,"夜热岛"强于"日热岛",变化幅度为-0.1～1.5℃。一年中夏秋季节热岛强度比冬春季节热岛强度明显,其中夏季最为明显。春、夏、秋、冬四季分别为-0.16～1.16℃、0.12～2.44℃、-0.09～1.49℃、-0.27～0.95℃;③唐山市上半年(1月-6月)的热岛强度高于下半年(6月-12月),气温跃变后唐山站与周围各站之间的热岛强度均大于全系列热岛强度;④人口总量、人口密度、建成区面积是城市热岛强度的主要影响因素,产业结构(重工业比例)也可能是影响热岛效应的主要因素之一。 相似文献
4.
典型河谷型城市冬季热场分布和热岛效应特征及其驱动机制研究——以兰州市为例 总被引：2，自引：1，他引：1
应用城市气候流动观测、定点观测、GIS空间分析等方法,模拟分析典型河谷型城市—兰州市的冬季热场、湿度场空间结构特征和演变规律;通过波文比系统观测实验,分析地—气能量交换过程和能量平衡特征,从根源上解释城市热场演变和城市热岛效应产生的能量驱动机制.利用观测数据,结合兰州城区和郊区气象台站1958-2004年的常规气象观测资料,分析冬季热岛强度的日、季节和年际变化特征,兰州市冬季热岛强度夜间强,白昼弱,一日中热岛强度最高的时段主要集中在子夜前后;个别时段的正午前后会出现短暂的城市“冷岛”现象;冬季热岛强度最强,夏季最弱,春秋居中;兰州市近50年热岛强度逐渐增强,线性趋势达到0.46℃/10a.定量分析城市化指数与热岛强度变化的关系,发现兰州市总人口、建筑面积与城市热岛强度都呈显著的线性相关关系.研究结果为河谷型城市的大气污染治理、生态环境建设、城市规划、土地利用等提供理论参考. 相似文献
5.
典型重工业城市热岛效应特征分析 总被引：1，自引：1，他引：0
本文选取唐山这座典型重工业城市，以地震后的气象资料（1977年-2006年）和2006年7月1日-2007年6月30日对比观测资料，采用统计分析方法对热岛效应特征进行研究与对比分析，结果发现：①1977年-2006年间热岛强度平均为0.51℃，最近10年热岛强度平均为0.82℃；②热岛效应的日变化明显，“夜热岛”强于“日热岛”，变化幅度为-0.1～1.5℃。一年中夏秋季节热岛强度比冬春季节热岛强度明显，其中夏季最为明显。春、夏、秋、冬四季分别为-0.16～1.16℃、0.12～2.44℃、-0.09～1.49℃、-0.27～0.95℃；③唐山市上半年（1月-6月）的热岛强度高于下半年（6月-12月），气温跃变后唐山站与周围各站之间的热岛强度均大于全系列热岛强度；④人口总量、人口密度、建成区面积是城市热岛强度的主要影响因素，产业结构（重工业比例）也可能是影响热岛效应的主要因素之一。 相似文献
6.
杭州湾城市群热岛时空特征分析 总被引：2，自引：0，他引：2
利用1970-2006年的常规气象站温度观测数据和Landsat-5 TM影像,选取杭州湾三个地区具有代表性的城市站和乡村站,根据亮度温度计算模型反演三个研究区域的亮度温度,研究杭州湾地区城市热岛效应37年来时间演变特征和空间分布特征.结果表明:(1)杭州湾地区城市热岛效应37年来显著增强.热岛强度以0.13℃/10年的速率加剧.热岛强度在2001年最强.分析三个地区1970-2006年的热岛强度时间演变,杭州地区最强、绍兴地区次之、宁波地区最弱;(2)杭州地区、绍兴地区、宁波地区热岛强度与人口的关系模型,显示相关系数分别为0.8695、0.8366、0.9287,表明城市热岛强度变化与城市人口变化呈线性正相关关系;(3)三个地区城市热岛强度的空间特征表明,绍兴地区的热岛强度明显强于其他两个地区,杭州地区次之,宁波地区最弱. 相似文献
7.
北京市夏季城市热岛特征及其近地层气象场分析 总被引：11，自引：1，他引：11
应用1998-2003年7、8月份的北京市10个气象台站和一个自动台站观测资料以及大气所325米气象塔的观测资料，对北京市的夏季城市热岛特征及其气象场进行了分析。结果表明：北京市夏季城市热岛现象明显，1998-2003年期间平均热岛强度达到1.64℃；强热岛主要发生在夜间，02时的平均热岛强度为2.62℃。而白天城市热岛减弱较快，14时的平均强度为0.6℃，有时甚至会出现冷岛现象；随着北京市城市化进程的不断深入，其城市热岛强度>2℃的天数也在逐年增加，最强时可达9℃；当热岛强度很强时，北京市近地层的风场会出现较明显的热岛环流（辐合），且风速较小（<2m/s）。结合大气所325米气象塔的观测资料可以发现：城市强热岛出现时，北京市的大气边界层逆温不仅强，而且逆温层顶较高。 相似文献
8.
基于标准化降水指数的云南省近55年旱涝演变特征 总被引：6，自引：1，他引：5
21世纪以来极端气候事件频发,其中旱涝灾害对人类影响最为明显。本文以云南省为例,选用标准化降水指数SPI(Standard Precipitation Index)为干旱指标,计算了1958-2012年近55a的29个气象站点5种不同时间尺度上的SPI值,在此基础上分析不同年及季节的旱涝站次比和旱涝强度的变化特征。结果表明:干旱强度在各时间尺度上均呈不同程度增加趋势,春季、秋季、冬季干旱强度及影响范围均呈现增加趋势,夏季干旱的强度和影响范围总体上呈略微下降趋势。雨涝强度在时间尺度上呈下降趋势;夏季雨涝强度和雨涝影响范围呈现略微上升趋势,其他季节均呈现出下降趋势。在当前气候变化背景下,云南省干旱整体上反映对农业生产不利影响加重的态势。研究表明标准化降水指数能够在较长时间系列尺度上很好地反映研究区年际及季节性旱涝变化特征。 相似文献
9.
利用2020年9月～2022年8月青海省冷湖赛什腾山区域自动站小时风向风速数据，按照年、季节、月、昼夜分别统计分析赛什腾山的风向和风速变化规律；同时按照季节、月分析了赛什腾山大风日数的出现频次和出现占比。结果表明:赛什腾山全年盛行风以W-NW为主，次盛行风为S-SW，偏东风的次数较少；春季盛行风向是SSW-WSW方向；夏季盛行风向为NE，次盛行风为SSW-WSW；秋季风向频率最高为SSW，次主导风为WNW-NNW；冬季风向所占比例最高为W-WNW。昼夜盛行风差异较大，夜间盛行风以西北风为主，白天盛行风以西南风为主。赛什腾山平均风速逐月和季节变化特征明显，10月份开始风速逐步增大，至5月达最大，以后风速逐步减小。季节排序为春季>冬季>秋季>夏季，冷湖地区与赛什腾山风速月际、季节和日变化不相同，可能是赛什腾山和冷湖站地形、海拔不同等原因造成的。 相似文献
10.
基于CI指数的辽宁省气象干旱特征分析 总被引：7，自引：3，他引：4
采用综合气象干旱指数,利用辽宁省22个气象站点1958年-2008年逐日降水和气温资料,从干旱强度、干旱持续时间和干旱频率三方面对辽宁省近50年年际和季节干旱特征进行分析。研究结果表明：辽宁省冬季无干旱事件发生;年际、夏季和秋季干旱程度均呈现显著增加趋势,春季干旱程度略微增加;年际、春季、夏季和秋季干旱程度分别在2000年、2001年、2000年和1999年最强;辽宁省年际干旱分布特征较集中,辽东不易发生年际干旱且持续时间短,辽南发生年际干旱频繁且持续时间长;季节干旱分布特征较分散,辽东春季不易发生干旱且持续时间短,辽南和辽西夏季发生干旱频繁且持续时间长,辽宁省普遍发生秋旱较轻。研究结果与实际情况基本相符,可为辽宁省相关部门根据本地区干旱特征制定相应抗旱对策提供理论依据。 相似文献
11.
《中国科学院院刊(英文版)》2008,22(1):2-3
CAS should stick to the principle of rendering service to, and giving impetus for, the development of China＇s science enterprise by making S＆T innovations, said CAS President LU Yongxiang. The CAS president made the remarks in a recent talk to communicate the gist of the winter session of the Party＇s Leading-member Group at CAS, which was held from 7 to 11 January in Beijing. 相似文献
12.
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
13.
《中国科学院院刊(英文版)》2008,22(1)
With great care, Dr. ZHOU Zhonghe takes out a package wrapped by cotton tissue from a drawer and says: "This is the gem of our collections: the fossil of a bird that lived 125 million years ago!" Then, pointing at a tiny mound, he explains: "Look, this is the claw and that is the head. It was in the egg shell and ready to hatch ... The species fell into a family of waterside inhabitants." 相似文献
14.
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
15.
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
16.
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
17.
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
18.
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
19.
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
20.
Prof. SUN Changpu from the CAS Institute of Theoretical Physics coworkers from University of Basel in Switzerland have worked out a way - at least in theory - to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams is similar to the famous Stern-Gerlach effect whereby a beam of atoms passing through a magnetic field is split in two according to the atoms' spin states 《中国科学院院刊(英文版)》2008,22(1):23-23
Prof. SUN Changpu from the CAS Institute of Theoretical Physics and coworkers from University of Basel in Switzerland have worked out a way --at least in theory --to split a beam of molecules according to their chirality. The technique involves passing the molecules through three different laser beams and is similar to the famous Stern-Gerlach effect, whereby a beam of atoms passing through a magnetic field is split in two according to the atoms＇ spin states （Phys. Rev. Lett. 99 130403）. 相似文献