Numerical Simulations of High‐Frequency Gravity Wave Propagation Through Fine Structures in the Mesosphere
Numerical Simulations of High‐Frequency Gravity Wave Propagation Through Fine Structures in the Mesosphere
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DOI：
10.1029/2018jd029746
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发表时间：
2019-08
期刊：
影响因子：
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通讯作者：
Tyler S. Mixa;D. Fritts;T. Lund;B. Laughman;Ling Wang;L. Kantha
中科院分区：
文献类型：
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作者：
Tyler S. Mixa;D. Fritts;T. Lund;B. Laughman;Ling Wang;L. Kantha
使用滞弹性数值模型来研究风中精细结构（FS）和稳定性剖面对中层和低热层（MLT）中重力波（GW）传播的影响。与 FS 相互作用的大振幅 GW，即增强风和稳定性的薄区域，根据 FS 梯度引起的小尺度运动的精确涡度源和汇项，其演化非常不同。由此产生的小尺度动力学是确定性的，在由初始 FS 确定的位置和方向上促进局部不稳定性、耗散和动量沉积。由此产生的动量沉积对背景风结构产生显着变化，其规模和幅度与周围大气中大尺度特征的影响相当。大规模影响的确定性进一步表明，可以在不完全解决潜在的不稳定动态的情况下对其进行估计。鉴于 FS 在整个大气中的显着幅度和普遍存在，这些重要且多样化的流动演化的影响值得纳入更广泛的建模工作中。
An anelastic numerical model is used to study the influences of fine structure (FS) in the wind and stability profiles on gravity wave (GW) propagation in the Mesosphere and Lower Thermosphere (MLT). Large amplitude GWs interacting with FS, that is, thin regions of enhanced wind and stability, evolve very differently depending on the precise vorticity source and sink terms for small‐scale motions induced by the FS gradients. The resulting small‐scale dynamics are deterministic, promoting local instabilities, dissipation, and momentum deposition at locations and orientations determined by the initial FS. The resulting momentum depositions yield significant changes to the background wind structure, having scales and amplitudes comparable to the effects of large‐scale features in the ambient atmosphere. The deterministic nature of the large‐scale impacts further suggests that they can be estimated without fully resolving the underlying instability dynamics. Given the significant amplitudes and ubiquitous occurrence of FS throughout the atmosphere, the influences of these important and diverse flow evolutions merit inclusion in broader modeling efforts.