3D Numerical Simulation of Secondary Wave Generation From Mountain Wave Breaking Over Europe
3D Numerical Simulation of Secondary Wave Generation From Mountain Wave Breaking Over Europe
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DOI：
10.1029/2021jd035413
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发表时间：
2022-02
期刊：
影响因子：
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通讯作者：
C. Heale;K. Bossert;S. Vadas
中科院分区：
文献类型：
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作者：
C. Heale;K. Bossert;S. Vadas
在本文中，我们模拟了一个观察到的山波事件在欧洲中部和调查的后续生成，传播，相速度和空间尺度，和动量沉积的次级波在三种不同的潮汐风条件下。我们发现山波在中间层的最低临界水平之下破裂。当山波破碎时，它沿着与其原始位置下游的破碎流相关的相和流体向外延伸500- 1，000 km。破裂产生了广泛的次级波，水平尺度从山波不稳定尺度（20-300公里）到山波包尺度（420公里以上）的倍数，在低热层中的相速度从40米/秒到150米/秒。次级波形态由半同心模式组成，波的传播通常与中间层中的局部潮汐风相反。潮汐风中的切变导致次级波的破碎和局部波强迫，从而产生更多的次级波。潮汐风也影响到达热层的次级波的主波长和相速度。到达热大气层的次级波将其能量和动量存款存放在热大气层的广大区域，主要集中在震源以东，高度在110至130公里之间。二次波强迫是显着的，可能是非常重要的热层的动力学。这种强迫的很大一部分来自于非线性产生的相对小尺度的二次波，这些二次波是由波浪破碎过程产生的。
In this paper, we simulate an observed mountain wave event over central Europe and investigate the subsequent generation, propagation, phase speeds and spatial scales, and momentum deposition of secondary waves under three different tidal wind conditions. We find the mountain wave breaks just below the lowest critical level in the mesosphere. As the mountain wave breaks, it extends outwards along the phases and fluid associated with the breaking flows downstream of its original location by 500–1,000 km. The breaking generates a broad range of secondary waves with horizontal scales ranging from the mountain wave instability scales (20–300 km), to multiples of the mountain wave packet scale (420 km+) and phase speeds from 40 to 150 m/s in the lower thermosphere. The secondary wave morphology consists of semi‐concentric patterns with wave propagation generally opposing the local tidal winds in the mesosphere. Shears in the tidal winds cause breaking of the secondary waves and local wave forcing which generates even more secondary waves. The tidal winds also influence the dominant wavelengths and phase speeds of secondary waves that reach the thermosphere. The secondary waves that reach the thermosphere deposit their energy and momentum over a broad area of the thermosphere, mostly eastward of the source and concentrated between 110 and 130 km altitude. The secondary wave forcing is significant and will likely be very important for the dynamics of the thermosphere. A large portion of this forcing comes from nonlinearly generated secondary waves at relatively small‐scales which arise from the wave breaking processes.