Resonating Neutral Modes of the Eady Model
Resonating Neutral Modes of the Eady Model
复制标题
Eady 模型的共振中性模式
DOI：
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发表时间：
1992
期刊：
影响因子：
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通讯作者：
E. Chang
中科院分区：
文献类型：
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作者：
E. Chang
摘要 中性Eady模式和具有相同相速度的连续模式之间的共振被用来解释Farrell所讨论的中性模式的增长。结果表明，如果其中一个能级非常接近中性 Eady 正则模式的转向能级，则这种共振的存在可能会导致离散准地转 (QG) 模型中误差的虚假线性增长。对于原始方程模型，这种寄生共振表现为一对呈指数增长衰减的短波。这种波与 Arakawa 和 Moorthi 在 QG 方程的洛伦兹网格中发现的波类似。然而，这里发现，对于原始方程模型，这些寄生短波对于洛伦兹网格和查尼-菲利普斯（CP）网格都存在，尽管CP网格的增长率要小一些。研究还表明，斯通讨论的非地转短波的增长率在垂直离散模型中被错误地高估了。
Abstract The resonance between a neutral Eady mode and a continuous mode with the same phase speed is used to interpret the growth of neutral modes discussed by Farrell. It is shown that the existence of such a resonance may lead to spurious linear growth of error in a discretized quasigeostrophic (QG) model if one of the levels lies very close to the steering level of the neutral Eady normal mode. For a primitive equation model, this spurious resonance manifests itself as an exponentially growing-decaying pair of short waves. Such waves are similar to those found by Arakawa and Moorthi for the Lorenz grid for the QG equations. However, here it is found that for the primitive equation model, these spurious short waves exist both for the Lorenz grid and the Charney–Phillips (CP) grid, although the growth rate is somewhat smaller for the CP grid. It is also shown that the growth rate of the nongeostrophic short waves discussed by Stone is erroneously overestimated in vertically discretized models.