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Dynamical Study of Planetary Waves with Hemispheric Scale by Using Rotating Dishpan Experiment.

利用旋转碟盘实验研究半球尺度行星波的动力学。

基本信息

批准号：
06640563
负责人：
SUDA Fujio
金额：
$ 1.09万
依托单位：
Tokai University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06640563/
关键词：
Geophysical Fluid Dynamics Non Linear Dynamics Rotating Dishpan Experiment Wave, Mean-flow Interaction Stratospheric Sudden Warming Polar Vortex Reversal Planeraly Waves Rossby Waves 惑星流体力学非線形力学系回転水槽実験極渦自然循環ループ画像解析

项目摘要

The Stratospheric Sudden Warming phenomena is characterized by not only the sudden warming but also the sudden reversal of winter type westerly polar vortex to the summer type easterly polar vortex. And it is well known that the basic scenario is written not thermally but dynamically, by using the propagating Rossby wave packet in the stratoshere. Therfore, it is not wrong that this phenomena is called as "Stratospheric Sudden reversal of Polar Vortex"In planetary scale atmospheric waves, the "local plane wave approximation", which is a premise in typical "Wave, Mean-flow Interaction" scenario, is not always satisfied. In such strong non-linear interaction, "through how process", "in how much area" and "at how much strength", the polar vortex reversal shall be cause?In order to answer such questions, the above scenario was much more simplified, and a new type experimental equipment, in which the behavior of hemispheric Rossby waves was simulated, was set up.In our experiment, the cente … More r and the side of our rotating cylindorical water pool correspond to the north pole and the low latitude region, respectively. By using this equipment, we succeeded to simulate the total process of excitation and horizontal propagation of steady Rossby waves, and further more the reversal of initial westerly polar vortex.As the result of this laboratory experiment, it was found that the final area and strength of polar vortex reversal are depend upon the strength of initial westerly polar vortex. By the velocity field analysis, the process of the vortex reversal was also found.Finally, a spherical barotropic numerical model which correspond to this experiment was set up, and the process of the polar vortex reversal was investigated in not only various strength of initial westerly polar vortex, but also various zonal wave numbers and strength of Rossby waves which are excited at low latitudes. As the result of this numerical experiment, it was found that there are some stable wave patterns which is easy to coexist with strong easterly polar vortex. Less

平流层突然增温现象不仅表现为突然增温，而且表现为冬季型西极涡向夏季东极涡的突然逆转。众所周知，基本情景不是热的，而是动态的，它是通过在平流层中传播的Rossby波包来编写的。因此，这种现象被称为行星尺度大气波中的“平流层极涡突然反转”并不是错误的，作为典型的“波-均流相互作用”情景的前提的“局部平面波近似”并不总是被满足。在这种强烈的非线性相互作用中，“通过怎样的过程”，“在多大的面积”和“在多大的强度”，极涡反转应该是原因？为了回答这样的问题，对上述情景进行了简化，并建立了一种新型的模拟半球Rossby波行为的实验装置。在我们的实验中，CENTE…更多的r和旋转圆柱形水池的一侧分别对应于北极和低纬地区。利用该装置成功地模拟了定常Rossby波激发和水平传播的全过程，进而模拟了初始西风极涡的反转过程。实验结果表明，极涡反转的最终面积和强度取决于初始西风极涡的强度。最后，建立了与实验相对应的球面正压数值模式，研究了不同强度的初始西风极涡，以及低纬激发的不同纬向波数和Rossby波强度下极涡逆转的过程。数值试验结果表明，存在一些稳定的波型，这些波型容易与强东风极涡共存。较少