阿拉尔市初夏一次大降水天气分析     

陈平  程强 《沙漠与绿洲气象(新疆气象)》2006,29(6):9-10,14

应用常规实况观测资料和数值预报产品,分析阿拉尔市2005年5月15日的一次大降水天气的环流形势和物理量场演变特征,发现数值预报产品对此次大降水预报有很好的参考价值,同时结合本站要素分析得到一些大降水预报的经验,对今后大降水预报有一定的借鉴作用。  相似文献   

From public neighbourhoods to multi-tier private neighbourhoods: the evolving ecology of neighbourhood privatization in Calgary     

Ivan J. Townshend 《GeoJournal》2006,66(1-2):103-120

The privatization of urban space, as represented in the trend towards a wide variety of common interest developments and increasing prevalence of gated communities, is an international phenomenon. Recent research has not systematically explored the ways in which these types of developments are collectively re-shaping the public and private realms of the city at large. This empirical study of community areas in a Canadian city describes a number of historical private neighbourhood development trends and their convergence in space and time. Based on the empirical generalizations, a conceptual model is developed to illustrate how the trends may have combined to produce a new geography or ecology of space privatization within the city, one in which the older public city is being circumscribed and bounded by new territories of multi-tiered privatization.  相似文献   

A step ahead of time: design, allocation and preservation of private open space in the 1920s––the case of a garden suburb in Israel     

Naftaly Goldshleger  Irit Amit-Cohen  Maxim Shoshany 《GeoJournal》2006,67(1):57-69

In the course of the last 50 years, the landscape in Israel has undergone major changes, due to accelerated urbanization following population growth. These processes had increased the pressure on the open land, especially in areas of urban expansion. Recognizing that Governments and local Municipalities had failed to stop the consequent loss of public open spaces, not only in Israel but worldwide, had lead recently many communities to adopt new solutions in the form of private open spaces. In this article we present a “step ahead of time”: a case of privately owned land, set aside as public green area during the 1920s in a neighborhood called “Ahuza Herbert Samuel” (Herbert Samuel, the first High Commissioner of Palestine under the British Mandate), located in the City of Haifa, in Northern Israel. The roots of this unique phenomenon during the 1920s could be linked to several sources of influence: Colonial town planning concepts, the emergence of garden cities and garden suburbs and most importantly to concepts brought in by the leaders of the immigrant community coming from Rumania. Photogrammetric and GIS analysis of this phenomenon had revealed that it had prevailed throughout 75 years of constant and massive increase in the demand for built-up areas in Israel in general and in Ahuza neighborhood in particular. The success in preserving these open areas gains current relevance in view of recent trends in the Western world of allocating privately owned green areas for public use.  相似文献   

一种城市形态中的空间可视分析方法   总被引：4，自引：0，他引：4  

应申  李霖  王红  高玉荣  彭晓艳 《测绘学报》2006,35(4):385-389

空间可视分析是空间句法的重要依据,是进行城市空间形态分析的新方法。在视域的行为指导原理上,采用可视集中性的概念来进行可视分析,进而通过可视分析各参数的具体量化,包括视域面积、视线长度等,将其应用到具体的城市街道形态中,分析各参数量化大小的分布情况。研究城市形态中可视分析通过“视域法则”影响人的行为,从而潜在决定城市内有关行人等基础设施的布局情况,现实中的设施分布也证明了这种分析的正确性。以武汉市中南地区为分析实例,说明上述各过程,验证城市形态对空间设施分布的影响。  相似文献   

Structure of flow over alluvial bedforms: an experiment on linking field and laboratory methods     

Alexander N. Sukhodolov  Juan J. Fedele  Bruce L. Rhoads 《地球表面变化过程与地形》2006,31(10):1292-1310

This paper presents results of a field study designed to examine the structure of flow over mobile and fixed bedforms in a natural stream and to compare the results with findings of previous laboratory studies within the framework of double time–space averaging approach. Measurements of turbulence were obtained in a small river in Illinois, USA, over a fine spatial grid of sampling points above a mobile sandy bedform and its artificially moulded replica. Flow structure over the artificial bedform is similar to that observed in laboratory studies, but is markedly different from the flow structure over natural bedforms. These differences are most pronounced in the roughness sublayer, whereas flow in the logarithmic layer over natural and artificial sand waves is fairly similar and exhibits spatial uniformity. The double time–space averaged distributions of turbulence statistics conform to the multilayer model of flow structure over bedforms. Mean velocity distributions indicate neither classical flow recirculation nor substantial reduction of velocities in the lee of bedform crests. However, vertical patterns of turbulence statistics over depth suggest that stacked wakes similar to those observed in laboratory studies exist above the bedforms. Thus, despite the absence of flow separation, wake development seems to be induced by the systematic influence of upstream bedforms on the vertical structure of turbulence. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

相空间地震波初至时刻拾取          下载免费PDF全文

姜少之  张志禹 《地震工程学报》2006,28(1):11-14

提出了一种新的地震波初至时刻拾取的方法,即将原始时间序列信号映射到相空间当中,通过其相空间图的特征进行初至时刻的拾取。相对于非常耗时的传统方法,本方法使得运算速度提高,结果更加精确稳定。  相似文献   

城市地质学发展前景展望   总被引：1，自引：0，他引：1  

潘懋  金江军 《城市地质》2006,1(1)

本文介绍了城市地质学的定义和研究内容,对国外、国内城市地质学发展历史进行了述评,对城市地质学的发展前景进行了展望。  相似文献   

对地质勘查组织“产品”设计的理解     

双秀丽 《中国煤田地质》2006,(Z1)

从讨论ISO 9000:2000标准“设计和开发”的定义出发,对地质勘查组织的的产品、产品质量特性和产品的设计进行了讨论,提出了地质勘查组织产品设计与标准中规定的设计和开发的概念以及对应关系,并对标准中的“设计和开发”与地质勘查组织“设计与开发”的内容进行了对比分析。  相似文献   

煤田地质勘查组织需“确认的过程”辩识     

王凤臣  双秀丽 《中国煤田地质》2006,(Z1)

对目前在煤田地勘单位贯彻ISO 9001:2000标准7.5.2条款中对需确认的过程的不同观点进行了分析,从“过程确认”的概念入手,并结合煤田地质勘查组织生产和服务提供过程及其特点,提出了煤田地质勘查单位需确认的过程的识别和控制方法。  相似文献   

区域GPS气象网站点合理布设的几点依据     

丁金才  叶其欣  马晓星  朱文耀  陆艳艳  仇欣  江飞 《气象》2006,32(2):34-39

区域GPS气象网反演的可降水量资料（GPS／PWV）对提高灾害性天气的监测和预报能力，改进数值天气预报精度已显示出广阔的应用前景，我国许多省市相继计划建设区域的GPS气象网。在区域GPS气象网中如何科学合理地布设GPS站就成了大家关注的问题。结合长江三角洲地区GPS气象网的情况，从长江三角洲地区的水汽通道，PWV分布的气候统计、GPS反演PWV资料的有效半径和在数值天气预报中资料同化的最大影响半径等4个方面，讨论了区域GPS网站点的分布和间距的几点依据：重点沿区域的水汽通道和强对流天气主要路径上布站，经向（南北向）的站点密度应大于纬向密度，站点的最大间距小于60km才能使反演的PwV的有效代表性和对数值预报的影响覆盖整个区域。 距  相似文献