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1.
西藏地区近35年气温变化的初步分析 总被引：1，自引：1，他引：0
本文分析了西藏地区近３５年温度变化的时空特征,发现近３５年平均气温处于波动变化,其变化幅度趋于平缓,总体特征呈升温趋势,四个分区无论冬季还是夏季,其温度都呈上升趋势,且冬季增温幅度大于夏季增温幅度,隆冬季节及盛夏季节的异常年具有持续性和连续性的特点,特别是进入９０年代后,隆冬季节的温度异常偏暖。 相似文献
2.
泰安气候变化特征分析 总被引：4，自引：0，他引：4
利用泰安气象局1994年～2002年8年的气温和降水数据,对泰安地区的气候变化特征进行了分析,发现泰安的气候变化对全球气候变化响应显著,气温明显升高,主要是冬季增温所至,降水波动下降,夏季降水明显减少。 相似文献
3.
近四十年西藏气温,降水的变化分析 总被引：2，自引：1，他引：1
通过对西藏地区历年气温、降水的变化分析,发现全区大部气温呈逐年上升趋势;夏季增温较冬季明显,气温异常主要出现在春夏两季,９０年代出现异常偏暖机率增多。降水主要集中夏半年,干湿季分明。降水的变化波动较大,各区域变化并不一致,呈现出较大的区域性。 相似文献
4.
中国华东及其周边地区NDVI对气温和降水的季节响应 总被引：6，自引：0，他引：6
地表植被与大气的相互作用过程是地球科学领域的研究重点和热点。本文基于SPOTVGT-NDVI数据和气象站点的气温和降水资料,采用时滞相关分析法,研究了1998年-2011年我国华东及其周边地区四季NDVI对气温和降水的时空响应特征。结果表明,在整个研究区,气温对NDVI的影响大于降水,NDVI与气温在夏季和秋季相关性较高,与降水在秋季和春季相关性较高,冬季NDVI与气温和降水相关性都最低。NDVI对气温响应的滞后期在春季和秋季较短,对降水响应的滞后期在冬季较短,夏季NDVI对气温和降水响应的滞后期都较长。在冬季、春季和秋季,NDVI对气温和降水最大相关系数的空间分布在研究区的南北部差异不明显,在夏季则具有较明显的南北差异。NDVI对气温变化响应的滞后期在春季、夏季和秋季具有较明显的南北差异,对降水变化响应的滞后期除在夏季具有一定的南北差异外,在其他季节空间分布规律性不显著。 相似文献
5.
太阳活动和大气涛动对天山南北气温波动的综合影响 总被引：3，自引：0，他引：3
利用天山南北33个气象站点1961-2012年逐日气温数据,运用滑动平均、线性倾向估计、Mann-Kendall非参数检验等气候诊断方法,分析了近52年天山南北气温变化趋势、突变特征,探讨了太阳活动、主要大气涛动对气温波动的综合影响。结果表明:①近52年天山南北气温暖化趋势明显。3个分区增温速率关系为:天山南坡(0.256℃/10a)天山北坡(0.259℃/10a)天山东段(0.446℃/10a);②天山南北气温变化与太阳活动波动具有一定的规律性,表现为:第19-20周期"反相关",第21-22周期和23周期上升段"正相关",第23周期下降段和第24周期"反相关";③ENSO事件对天山南北气温变化影响相对较弱,且ENSO事件强度与天山南北气温年际变化相关性存在不稳定性;④北极涛动(AO)和北大西洋涛动(NAO)与天山南北气温变化相关性较高且存在季节差异。其中,北极涛动(AO)主要影响天山南北冬季和春季气温变化,空间上天山北坡响应明显于南坡。北大西洋涛动(NAO)主要影响夏季气温变化,空间上夏季气温影响区域广泛,冬季气温影响主要集中在天山南北坡边缘地带;春季气温影响区域主要集中在天山北麓。 相似文献
6.
1951-2012年科尔沁沙地气温在突变前后的时空对比 总被引：3，自引：0，他引：3
为促进科尔沁沙地生态环境保护、农牧业发展、水资源合理开发利用等的顺利开展,本文利用1951-2012年科尔沁沙地气温资料,分析了该区气温突变特征及突变前后时空演变情况,结果表明：①时间上,年（季）最低气温首先发生突变（1981-1987年）,平均气温次之（1981-1994年）,最高气温最晚（1985-1999年）;冬、春、秋、夏季依次发生突变;②年最低气温突变后比突变前、冬季气温比夏季气温变化更剧烈;年、春（秋）季气温变化剧烈程度按最低、平均、最高气温依次减弱,冬季与之相反;③突变前春季最低气温升温速率为0.50℃/10a、突变后秋季最高气温升温速率为0.75℃/10a,二者对升温贡献最大;④突变前后多年均值增量最大为冬季最低气温（1.86℃）,气候倾向率增量最大为秋季最高气温（0.72℃/10a）;年内季节多年均值增量变化顺序与其增温速率增量变化相反;⑤空间上,年气温各要素突变后倾向率变化范围均较突变前增大,年最低气温突变后显著升温面积比突变前增大6.79%;突变后,除科左中旗地区平均气温外,自东向西沿新开河到西辽河以北地区升温速率大于以南地区升温速率。 相似文献
7.
拉萨近40年年平均气温变化特征的初步诊断分析 总被引：1，自引：0，他引：1
使用拉萨１９５２￣１９９５年年平均气温资料，对其基本气候特征，年代变化，气候突变，振荡周期，异常特征，持续特征等进行诊断分析表明：拉萨气温变化与全球，全国气温变化趋势基本一致，气温变化具有３个变暖期和２个变冷期；气候突变出现在６０、７０、８０年代初期；振荡周期有准２２年，准１１年，持续特征明显。 相似文献
8.
利用西藏色林错流域气象观测站1961～2008年逐月平均气温、降水量等资料,分析了近50牟流域气温、降水的年际和年代际变化特征和异常年份,结果表明：近50年流域年平均气温以0．40℃／10a的速率显著升高,冬季增温最突出。平均最高气温除夏季变化趋势不大外,其它各季以0．21～0．35℃／10a的速度显著升高;年平均最低气温以0．56℃／10a的速度显著升高,明显高于最高气温的井幅。流域年降水量以20．4mm／10a的速率呈显著的增加趋势,四季降水量表现为增加趋势,为0．8～10．4mm／10a,以夏季增幅最大。20世纪60年代至90年代,除夏季外,其它3季和年平均气温都表现为逐年代增加趋势。年、季平均最高气温的年代际变化特征不明显。60年代流域降水表现为偏少的年代际变化特征;70年代夏季降水偏多,其它季节偏少;80年代夏、秋两季降水正常,冬、春季偏多;90年代,夏季偏少,秋、冬季偏多;进入21世纪前8年,秋季降水偏少,其它三季降水偏多,年降水量增幅明显。 相似文献
9.
利用杭州国家基准气候站1951-2016年地面观测资料,分析了近66年杭州市气候变化特征。结果表明:杭州市气温呈极显著的上升趋势,最低气温上升最快,平均气温次之,最高气温相对较慢;冬、春季增温最快,秋季次之,夏季最为缓慢;气温一般在90年代至2000年发生突变,之后气候显著变暖。降水主要集中在春季和夏季。近66年杭州市春季和秋季降水量减少,而夏季和冬季降水量增多,年降水量呈波动变化特点,2000年之后,年降水量有增大之势。暴雨发生次数对年降水量的贡献作用举足轻重。分析发现未来杭州市年降水量和年暴雨日数增多的概率均较大。杭州市气候变化普遍存在较长尺度的32～34年及较短尺度的准2年振荡周期。 相似文献
10.
杨雪昆 《内蒙古科技与经济》2015,(5):45-46,55
利用鄂尔多斯市8个气象台站1961年~2013年逐月平均气温、降水量资料,用趋势分析和累积距平、信噪比等方法,分析了鄂尔多斯市近53a的气温和降水变化特征。结果表明:1年平均气温上升趋势明显,近53a升温2.1℃,且通过0.001显著检验,突变发生在1986年,近13a是最温暖时期。四季与年平均气温变化趋势基本一致,但略有不同。增温幅度冬季最大,夏季最小;突变时间秋季最早,夏季最晚。2年降水量略呈减少趋势,近53a仅减少1.4mm,四季降水量的变化不同步,夏、秋季降水趋于减少,冬、春季略有增加,相关系数均未达到0.10的显著水平。 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.
《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
15.
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
16.
《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
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.
《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