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1.
方斌贤  温家洪 《极地研究》2000,12(2):143-156
通过分析南北极地区文献数据库 ( AAR CD- ROM) ,极地文献数量、极地主要学科文献数量、极地冰川学科及其分支的文献数量在不同时期的发展变化情况 ,得出的主要结论有 :自 1 70 3年有第一篇极地文献到 1 90 0年间 ,极地文献数量不多 ,1 90 0年左右时间的文献量有一个增量 ,从1 957~ 1 958年的国际地球物理年以来 ,南极研究得到很大发展 ,北极研究则是在 1 970年以来有更大的发展 ,这样的发展势头继续保持着 ;极地研究的有大量的极地冰川文献 ,其次是极地海洋、极地地质、极地生物等学科文献 ;南极地区学科侧重点有天文、大气、地质、生物等学科 ,北极地区侧重在海洋、资源、环境等学科 ;南极研究中发展最快的学科有环境科学、信息科学 ,在北极地区 ,环境科学、生物科学、信息科学和医学的发展较为迅速 ;极地冰川学科与其它学科产生交叉研究 ,出现了一些新的分支 ,学科交叉发展和分支现象在极地的其它极地学科领域也普遍存在 ,也是极地学科发展变化的趋势之一。  相似文献   

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ABSTRACT. Miami is the primate city in a system of urban settlements that make up a Cuban ethnic archipelago in the United States. The city is also a national magnet, attracting Cuban migrants from metropolitan regions across the archipelago. Four large secondary cores of Cubans outside Florida serve as major “feeders” to the Miami enclave: northern New Jersey, New York City, Los Angeles, and Chicago. Currents of migration to Miami are especially strong among older, foreign-born, and disadvantaged Cubans, an indication of segmented paths in Cuban assimilation. Although concentration in Metropolitan Miami has been the Cuban story over the past three decades, processes of deconcentration now may well be under way.  相似文献   

3.
王慧  华滢  杨冰  马淑英 《极地研究》2011,23(3):178-182
利用DMSP卫星粒子数据,对南北半球20 000多个亚极光区极化流(SAPS)事件进行统计学分析,重点研究SAPS的发生率及其发生位置隧季节和世界时的分布,研究表明:(1)SAPS的发生率有明显的季节和世界时依赖性,主要发生在春秋季节,显示出较强的地磁活动依赖性;(2)SAPS在冬至也较多发生,可能与亚暴过程有关;(3...  相似文献   

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This paper questions the validity and relevance of the application of procedures of classical statistical inference to population data in geography. Arguments for such procedures include the notions of temporal and spatial samples, measurement error, modifiable areal units, data vetting and stochastic processes. It is concluded that such arguments cannot be justified in terms of statistical theory.  相似文献   

5.
景观格局的数量研究方法   总被引:168,自引:12,他引:156  
张金屯  邱扬  郑凤英 《山地学报》2000,18(4):346-352
依据景观局数量方法的研究进展,从单个斑块特征分析、单一景观要素的格局分析及景观镶嵌体特征分析等三个方面介绍了数量分析方法,并介绍最常用的和近年来发展的新方法。  相似文献   

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《Urban geography》2013,34(5):477-485
It is generally known that many traditional measures of segregation cannot distinguish different spatial population patterns. Several spatial measures of segregation have been proposed to overcome this problem, but these spatial measures are difficult to use because they require explicit spatial information and complex computation. This paper shows that Geographic Information Systems (GIS) can provide the spatial information required by these indices and that statistical packages can offer the complex computation functions needed to calculate the indices. We use ARC/INFO as the GIS package and S-Plus as the statistical package to demonstrate how spatial segregation indices can be calculated by combining the capabilities of these two types of systems.  相似文献   

8.
为了更好地开展强对流监测、预警和开展人工防雹作业指挥工作,通过对2006年至2012年昆明多普勒雷达观测的1148幅回波和234个降雹过程进行了收集和整理,从人工防雹作业指挥判别雹云的角度,对雷达回波的强度、高度和VIL等要素进行了统计分析。统计分析表明,云南滇中地区强对流发展强度强、高度高;虽然仅通过VIL跃升值难以判别强对流云体能否产生降雹,但冰雹云发展存在明显的VIL跃升,进而得出了强对流云体的VIL跃升值(前后两回波的VIL差值)是否超过35kg/m^2,可以作为强对流云体能否产生降雹的指标这一结论。  相似文献   

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Thirty years of data are examined for the last spring freeze and first autumn freeze at freeze thresholds of 0°C, -2.2°C, and -4.4°C. Four statistical conclusions of a 1958 Iowa freeze hazard study are tested in New York. The time series of freeze dates are random and normally distributed. Spring and autumn freeze dates are independent at a station. The variances of autumn freeze dates are homogeneous throughout New York and variances of spring freeze dates are homogeneous within each of three regions of similar climate. Statistical properties of the freeze date time series should be examined locally before results of studies in other regions are used. (Key words: freeze, frost, climatology, growing-season, New York, statistical methods.)  相似文献   

13.
关勇 《干旱区地理》1995,18(3):32-38
本文使用文献计量学中的引文分析方法,以《干旱区地理》为调查样本进行了统计分析。《干旱地理》1985-1994年共版43期,刊登论文558篇,其中附有引文的论文436篇,引文2766条。  相似文献   

14.
黄河下游泥沙淤积的经验统计关系   总被引:4,自引:0,他引:4  
许炯心 《地理研究》1997,16(1):23-30
以黄河下游历年实测水文泥沙资料为基础,运用多元回归分析方法,建立了下游河道淤积量与淤积强度的经验统计关系。揭示了不同粒径组泥沙的来量和它们在全沙中所占的比率对下游河道淤积特征的影响。同时,研究了高含沙洪水及清水基流对下游河道淤积的影响。  相似文献   

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河相关系研究的各种方法及其间关系   总被引:4,自引:1,他引:4  
倪晋仁  张仁 《地理学报》1992,47(4):368-375
河相关系的研究旨在寻求河床地貌形态与流域因子的定量关系。除了传统的水文统计方法外,已有多种理论被用来对这一问题进行探索,这些研究方法相互之间都存在一定的关系,发现和认识这些关系将对河相关系的研究产生深刻的影响。本文在这方面作了探讨。  相似文献   

18.
THE REMANENT MAGNETISM OF ARTIFICIALLY DEPOSITED SEDIMENTS   总被引:1,自引:0,他引:1  
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19.
《极地研究》1990,1(1):58-66
During 1985-1986, 1986-1987, and 1988-1989 expeditions on Fildes Peninsula the ground temperature was measured. A total number of 218 ground temperature data were obtained. The thermal conductivity measurements were made on 121 rock samples collected during expedition. This article gives a brief analysis and summarization of these data.  相似文献   

20.
Concepts relevant to statistical inference testing are discussed within a framework which contrasts conventional methodology with current trends in statistics. The latter are emphasized as having the quality of being less restrictive than the former. To show this quality, randomization testing is described and an example presented. Also described is a nonparametric technique known as QAP, which is particularly versatile. Optimism is expressed about the potentiality of such procedures for geographic research.  相似文献   

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