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Two alternative approaches for the depiction of the geographic distribution of diurnal precipitation patterns are presented. The standard deviation method results in a plot of significant peak precipitation hours for several locations along a transect. The correlation fields approach allows researchers to visualize geographic patterns significantly associated with a given diurnal precipitation distribution. These techniques may be applied to reveal changes in diurnal patterns over both space and time.  相似文献   

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Observations of hourly wind speeds and directions were taken over a 56-day period in summer 1978, at the 3,000 m ground level near an INSTAAR mountain research site on the east slope of the Front Range, Colorado Rockies. During nearly calm weather, which persisted for longer periods than normal in summer 1978, the pattern of diurnal wind variations resembles results from other mountain studies of wind along high mountain slopes. However, timing of high wind speeds during the daily cycle is not readily explainable, although hypotheses can be offered. Results of this study can assist in interpretations of forest clearing microclimates at high elevations in the mountains and in important air quality questions (e.g., precipitation pH) in the Rocky Mountains.  相似文献   

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司有元 《地理研究》1982,1(4):63-72
本文应用群分析的方法,对1951-1980年9月分10°E-165°W,10°N-70°N范围内的500毫巴环流形势场进行分类,以便了解不同类型的大气环流特征以及在不同大气环流型影响下,丹江口水库区流域降水和平均入库流量发生变化的情况.进而为水库的调度方案的编制和洪水预报提供气候学依据.  相似文献   

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Recent research has highlighted the value of employing the idea of networks to describe the interrelatedness of today's globalizing economy. Networks facilitate flows of knowledge, ideas, managerial techniques and capital between firms both within and across political borders. This paper argues that the reconstruction of social connections through which information is created, given value and exchanged is fundamental to an understanding of not only contemporary but also historical patterns of economic globalization. We focus on the networks of the capitalist elite running 12 major multinational enterprises, active across British imperial territories, between c .1900 and c .1930. An examination is made of the economic and spatial interlocks between firms created by board members who were multiple directors. Social underpinnings of multiple directorates are examined by exploring the common, overlapping social spheres within which individuals engaged. A clearer grasp of the ways in which corporate activity operated in the early 1900s can provide a better understanding of the social context of global economic operations.  相似文献   

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本文根据1994年8~9月份阿拉斯加北坡巴罗地区降水的实测资料,初步探讨了本区夏季降水的化学特征及环境意义。结果表明:巴罗地区夏季降水的pH值比冬季高,平均值接近与大气CO2平衡时纯水的酸度状况;电导率值普遍较低,个别电导率值较高的样品可能与海盐粒子有关;样品的主要离子浓度与北极其它地区和青藏高原的降水化学成分相当,exSO42-基本接近于零,反映了受人类活动影响非常小的自然本底状况。研究认为巴罗地区是进行北极地区现代环境状况研究的理想地区之一。  相似文献   

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Each measurable hourly precipitation event during January at Lake Charles, Louisiana, over the 1951–80 period has been classified by associated synoptic weather type. Using Muller's synoptic classification, four types were found to produce rainfall over the study period. Frontal Overrunning accounted for 71% of the hourly events with an average hourly intensity of 1.78 mm. Frontal Gulf Return accounted for the greatest hourly intensity of the four types (3.05 mm) and accounted for 24% of the observations. The Gulf Return and Coastal Return types produced few hours of precipitation at this time of year owing to both the cooler surface temperatures which limit convection and the dominance of the frontal activity. The frequency of the events associated with these types varied significantly over the study period. The frontal-related weather types increased dramatically during the colder months, and also increased in association with El Nino events and related cyclogenesis in the western Gulf of Mexico. Non-frontal events were most common in the 1950s. This approach could be applied to hourly precipitation studies elsewhere so that processes underlying monthly and inter-annual climate fluctuations may be better understood. [Key words: Hourly Precipitation, Synoptic weather Types, Climate Fluctuations.]  相似文献   

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《Area》1998,30(1):5-6
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福建永安鳞隐石林成因的沉积学研究   总被引:2,自引:0,他引:2  
王雪瑜 《地理学报》1997,52(2):138-145,T001
通过福建省永安市大湖乡鳞陷石林地区两个剖面中埋藏石芽周围红色堆积物的沉积学研究,对鳞稳石林成因加以探讨。堆积物的粒度、矿物 、化学成分分析,以及石英砂表面的微结构,都证实了这些红色堆积物是没有经过搬运的石灰岩岩体的风化残积物,鳞隐石林是石灰岩在一个相当长时间的稳定环境里。  相似文献   

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We have collected and re-examined macroseismic information for large Central American earthquakes since the beginning of the period of instrumental recording about one hundred years ago, and combined this with a reassessment of early instrumental information to produce a catalogue of 51 events that, we believe includes ail those with magnitudes ( Ms ) greater than 7.0. We have reassessed surface-wave magnitudes by consulting station bulletins and we have derived a correction that gives an equivalent Ms for events of intermediate depth. We have also developed a regional relationship between Ms and seismic moment, which enables us to estimate the seismic slip rate across the Middle American Trench. Our best estimates give an average slip rate several times smaller than suggested convergence rates, but with the seismic slip in the central segment of the trench almost an order of magnitude smaller than that in the segments on either side. The low seismic slip rate may indicate aseismic crustal deformation  相似文献   

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