A 6.5‐day westward propagating planetary wave: Origin and characteristics
A 6.5‐day westward propagating planetary wave: Origin and characteristics
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DOI：
10.1029/97jd01464
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发表时间：
1997-11
影响因子：
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通讯作者：
C. Meyer;J. Forbes
中科院分区：
文献类型：
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作者：
C. Meyer;J. Forbes
1993年8月和9月期间，在80-100公里高度范围内的地面雷达和卫星数据中都观察到了一个周期为6-7天的大型（10-30 m s-1）向西传播的行星波。之前对这些数据的分析认为，这很可能是（1-2）罗斯比行星波（通常称为5日波）的表现，可能通过与平均纬向风的相互作用而转移到更长的周期。在这项研究中，全球尺度波浪模型（GSWM [Hagan et al.，1993]）分析了这波向西传播的特征。我们建议，所观察到的波不是多普勒频移的5天波，而是一个不稳定的模式，从上层中层的不稳定区域汲取能量，其实现是全球性的。利用大气不稳定性的概念确定可能的源区，并利用模式确定不稳定性驱动波的特征周期、增长率和扰动场。
A large (10–30 m s−1) 6–7 day period westward propagating planetary wave was seen in both ground radar and satellite data within the 80–100 km height regime during August and September 1993. Previous analyses of these data argue that it was most likely a manifestation of the (1–2) Rossby planetary wave commonly referred to as the 5-day wave, perhaps shifted to longer periods by interaction with the mean zonal winds. In this study the global scale wave model (GSWM [Hagan et al., 1993]) is used to analyze the characteristics of this westward propagating wave. We propose that the observed wave is not a Doppler-shifted 5-day wave but rather an unstable mode, drawing energy from unstable regions in the upper mesosphere, whose realization is global in scale. The concept of atmospheric instability is used to determine a likely source region, and the model is used determine the characteristic period, growth rate, and perturbation fields of the instability-driven wave.