Propagation of Envelope Solitons in Baroclinic Atmosphere   总被引：1，自引：0，他引：1  

Tan Benkui  Yin Dongping 《大气科学进展》1995,12(4):439-448

ＰｒｏｐａｇａｔｉｏｎｏｆＥｎｖｅｌｏｐｅＳｏｌｉｔｏｎｓｉｎＢａｒｏｃｌｉｎｉｃＡｔｍｏｓｐｈｅｒｅ￥ＴａｎＢｅｎｋｕｉ（谭本馗）（ＤｅｐａｒｔｍｅｎｔｏｆＧｅｏｐｈｙｓｉｃｓ，ＰｅｋｉｎｇＵｎｉｖｅｒｓｉｔｙ，Ｂｅｉｊｉｎｇ１００８７１）ＹｉｎＤ...  相似文献   

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   

正压大气有利发展扰动型与遥相关型的建立     

李志锦  纪立人 《大气科学》1995,19(3):277-288

本文讨论了夏季纬向不对称气候平均流下通过正压大气内部动力过程建立遥相关型的问题。首先详细描述和讨论了有利发展扰动型的概念及其计算方法。作为对比，对正规模不稳定进行了分析。结果表明，正规模的不稳定增长率很小，难以用于解释遥相关型的发展。而有利发展扰动型的计算分析表明，最有利发展的那些扰动型的振幅增长率同实际大气遥相关型的增长率相一致，并且这些有利发展扰动型都将演变为同实际大气相一致的遥相关型结构。从而提出了，至少部分实际大气遥相关型可以不依赖于异常外源强迫，而仅依赖于大气内部的正压过程即能量转换过程而建立起来。  相似文献   

Form-drag instability in a barotropic and a baroclinic atmosphere     

S. Rambaldi  G. Salustri  C. Pellacani 《Pure and Applied Geophysics》1985,123(1):141-153

We discuss the form-drag instability for a quasi-geostrophic channel flow. We first study the characteristics of this instability in a barotropic flow, considering in detail the influence of the meridional scale and discussing which structure of the perturbation zonal flow must be chosen in order to describe properly this instability.We then consider a continuous quasi-geostrophic channel model in which the topography enters only through the bottom boundary condition, and we discuss how in this case the effects of the form-drag are felt by the mean zonal flow through the ageostrophic mean meridional circulation. Because the meridional structure of the perturbation zonal flow cannot simply be extended from the barotropic to the continuous case, we show how to modify it properly.We then study the baroclinic model in the particular case of constant (in the vertical) basic-state zonal flow and show how this case closely resembles the barotropic, demonstrating the barotropic nature of the form-drag instability.Symbols _t is the partial derivative with respect tot. - _x is the partial derivative with respect tox. - _y is the partial derivative with respect toy. - represents the geostrophic stream function. - u is the eastward component of the geostrophic wind. - v is the northward component of the geostrophic wind. - u _a is the eastward component of the ageostrophic wind. - v _a is the northward component of the ageostrophic wind. - w is the vertical component of the wind. - f is the Coriolis parameter=2 sin f _o+y. - f _o is the Coriolis parameter evaluated at mid-latitude. - N is the Brunt-Vaisala frequency. - [A] is the zonal (x) average ofA at constantp andy. - <A> is the horizontal (x andy) average ofA at constantp  相似文献   

Methanesulfonic acid and non-sea-salt sulfate in pacific air: Regional and seasonal variations   总被引：4，自引：0，他引：4  

E. S. Saltzman  D. L. Savoie  J. M. Prospero  R. G. Zika 《Journal of Atmospheric Chemistry》1986,4(2):227-240

Concentrations of aerosol methanesulfonic acid (MSA) and non-sea-salt (nss) sulfate were measured at six island stations in the Pacific Ocean to investigate regional and seasonal patterns of organosulfur emissions and the origin of nss sulfate over the Pacific. The mean MSA concentrations, in g/m³, at the stations were: Shemya, 0.097±0.098; Midway, 0.029±0.021; Fanning, 0.044±0.012; American Samoa, 0.026±0.012; New Caledonia, 0.021±0.009; Norfolk, 0.024±0.019. The extremely high MSA levels found at Shemya indicate a major source of organosulfur emissions in the western North Pacific. Significant seasonal trends in MSA were observed, with higher MSA occurring during warm months. The amplitude of the seasonal variation was greatest at higher latitude stations. At Fanning and American Samoa, which have minimal input of continental material, there is a significant positive correlation between MSA and nss sulfate. MSA/nss sulfate ratios at other Pacific stations exhibit greater variability, which may be related to variations in: the input of continentally derived sulfate, the composition of oceanic organosulfur emissions, and atmospheric reaction pathways.  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   

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   

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