地震电磁辐射电极法干扰因素的讨论     

赵东坡  陈智勇  徐东红  田树德 《华北地震科学》1995,(1)

首先扼要介绍了电极法地震电磁辐射的仪器性能、干扰概况和干扰与异常的识别。通过大量资料相关分析表明，雷电、磁暴等空中电磁扰动信号，以及气温、降水等气象因素，都不是电极法电场观测地震电磁辐射的明显干扰因素；当地低空特强雷电和布极区附近的较大电气设备启闭，可造成干扰，但此干扰可以识别和排除。  相似文献   

简单的热带海气耦合波——Rossby波的相互作用   总被引：7，自引：0，他引：7       下载免费PDF全文

巢纪平  王彰贵 《气象学报》1993,51(4):365-393

在本文中分析了当大气和海洋中未经耦合前的自由波均为Rossby模时,经相互作用后所激发出的耦合波的物理性质。结果表明,由于大气和海洋的背景状态不同,可以激发出两类不稳定耦合Rossby波。一类波要求大气的背景场是斜压的,而海洋的混合层较深,即热容量较大。这是一类弱相互作用的不稳定波。另一类要求大气的背景场趋于正压性,而海洋的混合层较浅,即热容量较小。这是一类强相互作用的不稳定波。色散关系的计算表明,这两类不稳定波产生的物理机制也不相同。文中对解不同截断模的本征值问题提出了几种数学方法,同时还进一步提出了一种使大气和海洋自由Rossby模的色散关系不受歪曲的处理方法。  相似文献   

The partitioning of nitrogen oxides in the lower Arctic troposphere during spring 1988     

Jan W. Bottenheim  Leonard A. Barrie  Elliot Atlas 《Journal of Atmospheric Chemistry》1993,17(1):15-27

Surface observations of several nitrogen oxides in the Canadian high Arctic during the period March-April 1988 are reported. These include data on NO₂, the inorganic nitrates HNO₃ and particulate nitrate, and the organic nitrates PAN and C₃–C₇ alkyl-nitrates. It is found that the organic nitrates make up 70–80% of the sum of the measured nitrogen oxides. Based on concurrently measured sulphur oxides, the period of observation was divided into two halves with the first half representing less polluted, more aged air than the second. The preponderance of the organic nitrates was less in the first period than the second. In contrast, there was little difference in the inorganic nitrates and NO₂ concentrations. The dominant inorganic nitrate shifted from particulate nitrate in the first period towards gaseous HNO₃ in the second. No correlation between the nitrates (inorganic or organic) and O₃ was observed; although some indication of a positive correlation between NO₂ and O₃ has been reported earlier (Bottenheimet al., 1990). Possible explanations for these observations are proposed. A survey of other potential nitrogen oxides that may be present in the Arctic air but not measured in these experiments suggests that the nitrogen oxides not measured here constitute a minor fraction of the total reactive nitrogen (NO _y ).Paper submitted to the 7th International Symposium of the Commission for Atmospheric Chemistry and Global Pollution on the Chemistry of the Global Atmosphere held in Chamrousse, France, from 5 to 11 September 1990.  相似文献   

The distribution of light nonmethane hydrocarbons over the mid-Atlantic: Results of the Polarstern cruise ANT VII/1     

R. Koppmann  R. Bauer  F. J. Johnen  C. Plass  J. Rudolph 《Journal of Atmospheric Chemistry》1992,15(3-4):215-234

During the cruise ANT VII/1 (September/October 1988) of the German research vessel Polarstern the latitudinal distributions of several nonmethane hydrocarbons were measured over the Atlantic between 45°N and 30°S by in-situ gas chromatography.On the average, the highest mixing ratios of ethane, propane, i- and n-butane, ethene and acetylene were observed in the Northern Hemisphere around 40° N and just north of the intertropical convergence zone, respectively. South of the equator, a bulge in the mixing ratios of ethane and acetylene was observed indicating aged biomass burning emissions. This observation coincided with enhanced tropospheric ozone found in this region at this season. On the average ethane and acetylene mixing ratios were around 500 and 100 ppt, respectively, whereas the levels of the other NMHC were in the range of some ppt up to 100 ppt.compared with the results of the cruise ANT V/5 (March/April, 1987), the ethane mixing ratios in September/October proved to be a factor of 3 lower in the Northern Hemisphere and a factor of 2 higher in the Southern Hemisphere, probably due to seasonal effects. Possible causes are the higher OH radical concentrations in summer, which result in a faster removal of ethane or stronger emission from biomass burning which also peaks in the dry season.The relative pattern of the hydrocarbons just north of the ITCZ was very similar for both measurement series. In this region, the NMHC were advected by long-range transport from the continent, whereas generally the ocean itself acts as a major NMHC source. This is supported by the results of a balance calculation between oceanic emissions and atmospheric removal rates.  相似文献   

中层大气臭氧的全日盘掩日测量     

王英鑑  徐寄遥 《大气科学》1992,16(4):385-392

本文研究了日盘张角对掩日测量的影响,引进了日盘光辐射空间变化特性这一先验信息,提出了从全日盘掩日测量反演中层大气臭氧含量的新方法.数值模拟试验指出,这一方法可以满意地给出25—65km高度范围内大气臭氧的垂直分布。当测量吸收比的均方根噪声为0.01时,其反演误差小于10％.利用这一方法,可以大大简化探测系统、降低测量对遥感平台的要求.  相似文献   

THE LYAPUNOV STABILITY OF NONLINEAR WAVE MOTION IN THE BAROTROPIC NONDIVERGENT ATMOSPHERE          下载免费PDF全文

Luo Dehai 《Acta Meteorologica Sinica》1992,6(3):390-394

Introducing the concept of pseudo-momentum, a generalized Arnold-Dikii functional is established, and then thesufficient condition for stability of nonlinear wave motion in the barotropic nondivergent atmosphere is derived by useof variational principle. It is found that the stability of nonlinear wave motion depends not only on its streamfield distri-bution, but also on its phase speed for the propagating nonlinear wave motion. Moreover, the stability criterion of trav-elling modon is also obtained, and it is shown that the travelling modon is stable if the scale of disturbance superimposedon the travelling modon remains to be less than that of the travelling modon.  相似文献   

A review of gravity wave saturation processes,effects, and variability in the middle atmosphere     

David C. Fritts 《Pure and Applied Geophysics》1989,130(2-3):343-371

This paper provides a review of our current understanding of the processes responsible for gravity wave saturation as well as the principal effects and variability of saturation in the lower and middle atmosphere. We discuss the theoretical and observational evidence for linear and nonlinear saturation processes and examine the consequences of saturation for wave amplitude limits, momentum and energy fluxes, the diffusion of heat and constituents, and the establishment of a near-universal vertical wavenumber spectrum. Recent studies of gravity wave variability are reviewed and are seen to provide insights into the significant causes of wave variability throughout the atmosphere.  相似文献   

Generalised scale invariance and multiplicative processes in the atmosphere     

D. Schertzer  S. Lovejoy 《Pure and Applied Geophysics》1989,130(1):57-81

Many geophysical fields show highly intermittent fractal structures spanning wide ranges of scale. However, few are isotropic: texture, stratification, as well as variable (scale dependent) orientation of structures is far more common. To deal with such fractals, we must generalise the idea of scale invariance beyond the familiar self-similar (or even self-affine) notions. Taking the atmosphere as our primary example (however, we also model galaxies), we outline the necessary formalism (generalised scale invariance), and show how it can be used to deal with the strongly intermittent structures which result from multiplicative (cascade type) processes concentrating matter or energy into smaller and smaller scales.We illustrate these ideas with rain data from blotting paper and radar, showing first how to directly estimate the elliptical dimension characterising the stratification, and second, how to determine universal scale-independent (invariant) codimension functions that characterise the distribution of the intense rain regions.  相似文献   

京津唐张地区震级频度关系的空间扫描          下载免费PDF全文

马瑾  雷兴林 《地震地质》1990,12(3):229-236

对京津唐张地区地震震级频度关系进行空间扫描后,发现该区的震级频度关系有三种类型:第1类符合线性b值模型,第Ⅱ、第Ⅲ类符合特征震级模型。近22年来未发生大震的地区往往属第1类。大震区往往属第Ⅱ、Ⅲ类。岩石力学实验结果表明,在岩石破裂及破裂连结过程中声发射事件的震级频度关系符合高b值线性模型。在岩石伴有粘滑的摩擦滑动过程中声发射事件的震级频度关系符合低b值线性模型。但是在一个完整岩石的破裂和失稳错动全过程中声发射事件震级频度关系符合特征震级模型。由此说明某一区域的震级频度关系可能反映了该区构造变形所处的阶段。一个地区震级频度关系上的多次转折可能包含了地区构造几何信息。一些未发生大震的地区,在中等震级段出现b值非线性现象,这可能意味着它更接近失稳前的临界状态  相似文献   

四川盆地寒武系沉积成岩特征与油气储集性   总被引：14，自引：0，他引：14  

李天生 《矿物岩石》1992,12(3):66-73

本文利用地质、钻井、测井、试油、实验等有关资料,从沉积有利相带、利于孔隙发育的成岩后生作用角度,对四川盆地寒武系孔隙成因进行较深入探讨,结合喜山运动褶皱成缝对孔隙的进一步改造作用,对其储集条件作综合研究。最后,进行了含油气远景评价和勘探有利区块预测。  相似文献