A saturated inertia gravity wave in the mesosphere observed by the middle and upper atmosphere radar
A saturated inertia gravity wave in the mesosphere observed by the middle and upper atmosphere radar
复制标题
中高层大气雷达观测到的中间层饱和惯性重力波
DOI：
10.1029/jd092id10p11993
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发表时间：
1987
影响因子：
--
通讯作者：
S. Fukao
中科院分区：
文献类型：
--
作者：
M. Yamamoto;T. Tsuda;S. Kato;Toru Sato;S. Fukao
1985年2月8日，我们从中层和高层大气雷达观测中发现了一个垂直波长约为5.6公里的单色惯性重力波。通过假设重力波的线性色散和偏振方程，我们估计了重力波的固有周期和传播方向分别为8小时和向北。惯性重力波修正后的大气最小Richardson数在72公里附近略为负值，这意味着惯性重力波已饱和，并通过剪切和对流不稳定性产生湍流。我们观察到的回波功率增强的高度附近的最小理查森数。在68-78公里的高度，我们发现间歇性波动的径向风速的周期为9分钟。他们的相位迅速逆转73公里附近，其振幅达到最小值和理查森数小于1。这些波动似乎是由于饱和重力波产生的剪切或对流不稳定性。
We have found the dominance of a monochromatic inertia gravity wave with a vertical wavelength of approximately 5.6 km from middle and upper atmosphere radar observations of the mesosphere on February 8, 1985. By assuming linear dispersion and polarization equations for gravity waves, we have estimated the intrinsic period and propagation direction of the wave as 8 hours and northward, respectively. The minimum Richardson number for the atmosphere as modified by the inertia gravity wave was slightly negative near 72 km, which implies that the wave was saturated and generated turbulence through shear and convective instabilities. We observed an echo power enhancement near the altitude of the minimum Richardson number. At 68–78 km altitude we found intermittent fluctuations in radial wind velocities with a period of 9 min. Their phases rapidly reversed near 73 km, where their amplitudes reached a minimum and the Richardson number was less than 1. These fluctuations seem to be attributable to the shear or convective instabilities generated by the saturating gravity wave.