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51.
冬季城市边界层风场和温度场结构分析 总被引:15,自引:1,他引:15
本文根据沈阳地区大气环境容量研究中1984年12月所进行的观测,对沈阳城市边界层的流场和温度场结构做了分析。得出了冬季城市边界层的一些特征。当地面风速微弱时,热岛效应显著。边界层低层辐合抬升,在城市下风边缘可能出现反向气流。当风速较强时,城市的摩擦效应占优势,城市上风部分辐合抬升,下风部分辐散下沉。观测分析还表明,城市建筑对气流的阻滞作用可伸展到几百米的高度。夜间微风时,接地逆温层厚度可达200m,城市内边界层从上风边缘起开始发展,厚度可达100m。白天风力微弱时,重烟尘污染可导致城市冷岛,并推迟对流边界层的发展。 相似文献
52.
描述了强震现场流动无线遥测地震台网观测系统的技术设计,系统构成,工作原理及应用。 相似文献
53.
Sang Jianguo 《Acta Meteorologica Sinica》1987,1(1):112-117
The atmospheric thermodynamic equations are solved analytically to study the urban circulation caused by city heating.The perturbed flow and temperature fields are obtained and compared with observational facts from some urban boundary experiments.The agreement between the theoretical and observational results shows that this study may shed light on the physical characteristics of heat island circulation. 相似文献
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Wang Siyuan Xiao Qibing Zeng Jianguo Faculty of Earth Resources China University of Geosciences Wuhan 《中国地质大学学报(英文版)》2001,12(1)
-,The well-known Suichang silvengold field is located inZhejiang Province of SOutheast China. It is the largest silver-gold deposit associated with copper and zinc in the Cathaysianmetallogenic province.There are a series of silver-gold dePOsits in the shear zonesof Proterozoic gneiss terrene, Suichang region. The volcanicapparatus at Mesozoic has complicated rpineralization. Respectively, there are two pieces of understanding on the origin ofore-formigg nuid: (l ) metamorphic fluid (Lia… 相似文献
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Jianguo Sun 《Geophysical Prospecting》1996,44(3):351-374
Conventionally, the Fresnel zone and the geometrical spreading factor are investigated separately, because they belong to different theories of wave propagation. However, if the paraxial ray method is used for establishing the Fresnel–Kirchhoff diffraction formula for a laterally inhomogeneous multilayered medium, it can be shown that the normalized geometrical spreading factor is inversely proportional to the area of the first Fresnel zone associated with the reflection point. Therefore, if no diffracting edge cuts the first Fresnel zone, the geometrical optics approximation represents the principal part of the wavefield obtained by Fresnel–Kirchhoff diffraction theory. Otherwise, the geometrical optics approximation has to be corrected by adding edge diffractions. It is also shown that Kirchhoff-type migration and geometrical spreading factor correction both reduce the first Fresnel zone to a zone with unit area. 相似文献
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Du Jianguo 《中国地球化学学报》1992,11(3):237-243
Heat flow and the origin of helium in natural gases from fault basins of the continental rift-valley in eastern China are
discussed in terms of helium isotope geochemistry.3He/4He ratios in natural gases from the rift-valley range from 2.23 × 10−7 to 7.21 × 10−6, which are directly proportional to the concentration of helium and ΣNHC/ΣHC ratio in natural gases. Geological and isotope
geochemical data suggest that helium in natural gases consists predominantly of crustal radio-genic and upper mantle-derived
helium. In a simple mixing pattern between crustal He and mantle-derived He, mantle-derived helium in natural gases would
account for 10–60%. Calculated values for heat flow (Q) range from 59.7 to 82.4mWm−2, of which about 60 percent in the rift-valley is derived from the upper mantle. Natural helium reservoirs would be found
in the areas where the upper mantle uplifted greatly and heat flow is large in the continental rift-valley.
The project is financially supported by the National Natural Science Foundation of China. 相似文献