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21.
Sdsealbedoisdefinedasaratioofreflectivesolarradiationtototalacradiation,whichcanindicatetheaborptionandreflectivecapabilityofthe~hforsolarradiation.Itisan~tfactortoinfluencethes~radiationbalance,espeiallyfortheformationandvariationoflocalndcroclirnate.Generally,theactualdatafromo~tionalstationSforrebationareedintheanalysisofsolacealal.HOwever,therepresentativenessOfthedateisIratedduetothescarcityofobservationalstationandunevendistributionofs~condition.Afterthe1960s,theanalysisfors~ealbedoise… 相似文献
22.
Budong Qian 《中国地理科学(英文版)》1997,7(3):220-228
The precipitation patterns in flood season over China associated with the El Niño/Southern Oscillation (ENSO) are investigated, especially in the eastern China, using the rather long period rainfall data in this century. The results show that there were remarkable differences between the precipitation patterns in flood seasons of ENSO warm phase (El Niño year) and cold phase (La Niña year), as well as between the patterns in El Niño years and their following years. The most parts of China received below normal rainfall in flood season of the onset years of El Niño events, but the coastal area of Southeast China received above normal amounts. Comparatively, the most parts of China received above normal rainfall in flood season of the following years of El Niño events, but the eastern part of the reaches among the Huanghe (Yellow) River, the Huaihe River and the Haihe River, and the Northeast China received less. During ENSO cold phase, the reaches of the Changjiang (Yangtze) River and the North China received more amounts than normal rainfall in flood season of the onset years of La Niña events, and the other regions of China received less. In the following years of La Niña events, the coastal area of the Southeast China, the most part of the Northeast China and the regions between the Huanghe River and the Huaihe River received more precipitation during flood seasons, but the other parts received below normal precipitation. 相似文献
23.
T. H. BELL S. E. JOHNSON B. DAVIS A. FORDE N. HAYWARD C. WILKINS 《Journal of Metamorphic Geology》1992,10(3):295-307
Extensive examination of large numbers of spatially orientated thin sections of orientated samples from orogens of all ages around the world has demonstrated that porphyroblasts do not rotate relative to geographical coordinates during highly non-coaxial ductile deformation of the matrix subsequent to their growth. This has been demonstrated for all tectonic environments so far investigated. The work also has provided new insights and data on metamorphic, structural and tectonic processes including: (1) the intimate control of deformation partitioning on metamorphic reactions; (2) solutions to the lack of correlation between lineations that indicate the direction of movement within thrusts and shear zones, and relative plate motion; and (3) a possible technique for determining the direction of relative plate motion that caused orogenesis in ancient orogens. 相似文献
24.
讨论了应用曲面拟合技术和利用离散的重力观测点的重力变化对特定研究区的重力场变化进行数值模拟以获取该区重力变化空间梯度场图像的具体方法;并应用该方法获得了2004年3月福建安溪3.6级地震前的重力变化空间梯度场图像,发现空间梯度场图像能清晰地反映出地震前重力场群体性变化的差异性;利用此方法对2005年6月~2006年3月间台湾海峡西岸重力场变化进行数值模拟,获得其空间梯度场图像。 相似文献
25.
Kevin Fong 《Earth, Moon, and Planets》2004,94(3-4):169-176
Human space exploration is not considered a strategic priority in the United Kingdom at present. However the UK would benefit from participating in human spaceflight, for both scientific and social reasons. From the point of view of medical science there are many parallels between the physiology of spaceflight and terrestrial disease processes, and studies of the response of astronauts to long-duration spaceflight can therefore help in the development of therapeutic strategies on Earth. On the social side, human spaceflight is an attractive vehicle for stimulating the interest of young people in science and engineering, something that must be of value for an aspiring ‘knowledge-based’ economy. 相似文献
26.
应用GPS观测青藏高原东北缘应力场变化 总被引:2,自引:0,他引:2
采用各向同性弹性地球模型推导了地面位移场速率与地壳内任意点应力场变化的边界积分关系,同时利用青藏高原东北缘1999~2001年观测的GPS资料对观测区地壳深度为5 km和25 km的主应力和最大剪应力进行了计算分析.结果表明,青藏高原东北缘的主应力变化主要集中在祁连山断裂、海原断裂等,在1920~1954年间历史上发生过多次震级为7.0~8.5级强震的断裂附近,并具有主应力变化沿断层走向分布、最大剪应力沿断层走向交替变化等特征. 相似文献
27.
REGIONAL DEMOGRAPHIC STRUCTURE OF THE UNITED STATES 总被引:1,自引:0,他引:1
Richard L. Morrill 《The Professional geographer》1990,42(1):38-53
This paper analyzes the surprisingly great variation in demographic character across the states, utilizing data on fertility, mortality, age, sex, mobility, household character, abortion, race and ethnicity. A fairly simple regional pattern is revealed that is less related to levels of economic development than to long-standing historical cultural differences. 相似文献
28.
山区公路软基病害研究 总被引:2,自引:0,他引:2
随着高等级公路建设规模的扩大,山区公路所面临的路基病害特别是软土路基病害问题也逐渐增多。结合对陕南勉(县)一宁(强)高速公路工程实例分析,对山区软土成因及其特性进行了初步分析,认为山区软土属以坡洪积、湖积和冲积为主的软土,也有少量是由坡残积物堆积而形成。山区软土的特殊性表现在成分的复杂性、分布的不均匀性、隐蔽性和物理力学性质的特殊性。根据其特性以及中国山区公路软基普遍存在的病害问题,总结了山区公路软基的主要病害类型为剪切拉裂破坏、浸水沉陷破坏、剥蚀坍塌破坏、推挤滑动破坏。还提出了相应的软基处理方法及建议。 相似文献
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