The interaction between synoptic‐scale balanced flow and a finite‐amplitude mesoscale wave field throughout all atmospheric layers: weak and moderately strong stratification
The interaction between synoptic‐scale balanced flow and a finite‐amplitude mesoscale wave field throughout all atmospheric layers: weak and moderately strong stratification
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天气尺度平衡流与整个大气层的有限振幅中尺度波场之间的相互作用：弱层结和中强层结
DOI：
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发表时间：
2017
期刊：
影响因子：
--
通讯作者：
Rupert Klein
中科院分区：
文献类型：
--
作者：
U. Achatz;B. Ribstein;F. Senf;Rupert Klein
在对流层弱层结和平流层中等强层结条件下，重新考虑了局地单色有限振幅中尺度波及其非线性高次谐波与天气尺度流之间的相互作用。回顾f平面上准地转理论的基本假设，得出所有天气尺度都是用最少数量的自然变量表示的，即声速、重力加速度和科里奥利参数中的两个。定义了波的尺度，使得所有的空间和时间尺度在Rossby数中缩短一个数量级，并假设它们的浮力场接近静态不稳定性。应用WKB理论，以Rossby数为尺度分离参数，结合系统的Rossby数展开。恢复了天气尺度流量平衡和惯性重力波(IGW)动力学的经典结果。此外，还对中尺度地转模(GM)和天气尺度气流之间的相互作用进行了显式表示。结果表明，IGW的高次谐波受制于基波，其幅值比基波幅值小一个数量级。GM高次谐波并不是那么弱，它们与基本GM之间存在着强烈的非线性相互作用。可压缩动力学在平流层层结机制中起着重要作用，滞弹性理论在平流层层结机制中将产生不充分的结果。作为对经典推导的补充，结果还表明，在没有中尺度波的情况下，准地转理论也适用于平流层结。
The interaction between locally monochromatic finite‐amplitude mesoscale waves, their nonlinearly induced higher harmonics, and a synoptic‐scale flow is reconsidered, both in the tropospheric regime of weak stratification and in the stratospheric regime of moderately strong stratification. A review of the basic assumptions of quasi‐geostrophic theory on an f‐plane yields all synoptic scales in terms of a minimal number of natural variables, i.e. two out of the speed of sound, gravitational acceleration and Coriolis parameter. The wave scaling is defined so that all spatial and temporal scales are shorter by one order in the Rossby number, and by assuming their buoyancy field to be close to static instability. WKB theory is applied, with the Rossby number as scale separation parameter, combined with a systematic Rossby‐number expansion of all fields. Classic results for synoptic‐scale‐flow balances and inertia‐gravity‐wave (IGW) dynamics are recovered. These are supplemented by explicit expressions for the interaction between mesoscale geostrophic modes (GMs), a possibly somewhat overlooked agent of horizontal coupling in the atmosphere, and the synoptic‐scale flow. It is shown that IGW higher harmonics are slaved to the basic IGW, and that their amplitude is one order of magnitude smaller than the basic‐wave amplitude. GM higher harmonics are not that weak and they are in intense nonlinear interaction between themselves and the basic GM. Compressible dynamics plays a significant role in the stratospheric stratification regime, where anelastic theory would yield insufficient results. Supplementing classic derivations, it is moreover shown that, in the absence of mesoscale waves, quasi‐geostrophic theory holds also in the stratospheric stratification regime.
影响因子：
3.7
作者：
Jin-Han Xie;J. Vanneste
通讯作者：
Jin-Han Xie;J. Vanneste
DOI：
10.1002/2015ja021349
发表时间：
2015-08
期刊：
Journal of Geophysical Research: Space Physics
影响因子：
--
作者：
B. Ribstein;U. Achatz;F. Senf
通讯作者：
B. Ribstein;U. Achatz;F. Senf
差热旋转环实验的类大气结构中的重力波发射
影响因子：
3.7
作者：
Borchert;Achatz U;Fruman
通讯作者：
Fruman