Planetary Waves in the Thermosphere-Ionosphere System.
Planetary Waves in the Thermosphere-Ionosphere System.
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DOI：
10.5636/jgg.48.91
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发表时间：
1996-01
期刊：
影响因子：
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通讯作者：
J. Forbes
中科院分区：
文献类型：
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作者：
J. Forbes
在没有耗散的等温大气的极限下，控制大气运动的方程组允许对应于离散纬向波数和周期的“自由”（非强迫）振荡的解。属于旋转子类的全球振荡被称为自由Rossby波或Rossby简正模。尽管存在平均风、非等温性和耗散，这些波的大气表现显然存在。迄今为止，对这种振荡的研究主要限于对流层和平流层（0-50公里），其中包括扰动的源区。然而，越来越多的证据表明，自由Rossby波的影响延伸到中间层/低热层（约1000年）。80-150公里）和电离层（约。90-400公里）。目前的工作借鉴了最近的数值模拟结果和数据分析作为一个框架，讨论行星波的影响渗透到上层地区的大气，特别是电离层发电机区（CA。100-170公里）和随之而来的电动相互作用。注意力主要集中在波数s = 1（周期为5，10和16天）的向西传播的正常模式，和所谓的“2天波”，这通常是与混合Rossby重力模式与s = 3。
In the limit of an isothermal atmosphere without dissipation, the equations governing atmospheric motions admit solutions corresponding to “free” (unforced) oscillations for discrete zonal wavenumbers and periods. Global oscillations belonging to the rotational subclass are referred to as free Rossby waves or Rossby normal modes. Despite the existence of mean winds, nonisothermality, and dissipation, atmospheric manifestations of these waves apparently exist. To date the study of such oscillations has been confined mainly to the troposphere and stratosphere (0-50 km), which includes the source region for the disturbances. However, there is increasing evidence that the effects of free Rossby waves extend into the mesosphere/lower thermosphere (ca. 80-150 km) and ionosphere (ca. 90-400 km). The present work draws upon recent numerical modeling results and data analyses as a framework for discussing the penetration of planetary wave effects into the upper regions of the atmosphere, especially the ionospheric dynamo region (ca. 100-170 km) and the electrodynamic interactions which ensue there. Attention is primarily focused on the westward propagating normal modes of wavenumber s = 1 (periods of 5, 10 and 16 days), and the so-called “2-day wave” which is normally associated with the mixed Rossby-gravity mode with s = 3.