Acoustic-Gravity Wave Spectrum Filtering in the Horizontally Inhomogeneous Atmospheric Flow

IF 0.5 4区物理与天体物理 Q4 ASTRONOMY & ASTROPHYSICS

Kinematics and Physics of Celestial Bodies Pub Date : 2023-08-04 DOI:10.3103/S0884591323040049

A. K. Fedorenko, E. I. Kryuchkov, O. K. Cheremnykh, I. T. Zhuk

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引用次数: 1

Abstract—

The properties of acoustic-gravity waves (AGWs) in the atmosphere can be determined to a greater extent by the features of the propagation medium than by the sources of these disturbances. In the presence of spatial inhomogeneities of atmospheric parameters, significant deviations of AGW characteristics from theory are observed. This complicates the experimental diagnosis of waves and the search for a connection with their potential sources. AGW observations from the Dynamics Explorer 2 satellite indicates the predominance of waves with certain spectral characteristics in the polar thermosphere. It has been found that AGWs with large amplitudes are spatially consistent with areas of strong winds, while AGWs move mainly toward the wind. In order to explain the observed AGW properties, we investigate the filtering of the spectrum of these waves in the presence of a spatially inhomogeneous wind. It is shown that the direction and magnitude of the wave vector change in a special way in the oncoming inhomogeneous wind. In this case, with an increase in the speed of the headwind, the wave vector gradually tilts toward the horizontal plane. The vertical component of the wave vector decreases rapidly, and its horizontal component tends to some threshold value, which is predominant in observations. In addition, in the oncoming inhomogeneous flow, the frequencies and amplitudes of the waves increase. As a result, high-frequency wave harmonics with a small angle of inclination of the wave vector to the horizontal plane and a characteristic horizontal wavelength will prevail in a strong headwind from the continuous spectrum of atmospheric AGWs that can be generated by a hypothetical source. Since the wave vector and the group velocity vector in AGWs are almost perpendicular to each other, such waves provide efficient energy transfer in the vertical direction. In this regard, AGWs play an important role in the energy balance of the polar atmosphere by redistributing the energy of horizontal wind currents in the vertical direction.

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水平非均匀大气流动中的声-重力波频谱滤波

大气中声重力波(AGWs)的特性在更大程度上取决于传播介质的特性，而不是这些扰动的来源。在大气参数存在空间非均匀性的情况下，AGW特征与理论存在显著偏差。这使得波的实验诊断和寻找与潜在源的联系变得复杂。动力学探索者2号卫星的AGW观测表明，在极地热层中，具有某些光谱特征的波占主导地位。研究发现，振幅较大的AGWs在空间上与强风区一致，且主要向风方向移动。为了解释观测到的AGW特性，我们研究了在空间非均匀风存在下这些波的频谱滤波。结果表明，在迎面而来的非均匀风中，波矢量的方向和大小以一种特殊的方式变化。在这种情况下，随着逆风速度的增加，波矢量逐渐向水平面倾斜。波矢量的垂直分量迅速减小，而其水平分量趋于某个阈值，在观测中占主导地位。此外，在迎面而来的非均匀流动中，波的频率和振幅增加。因此，假设源产生的大气AGWs的连续谱中，波矢量与水平面的倾角较小且具有特征水平波长的高频波谐波将在强逆风中占上风。由于AGWs中的波矢量和群速度矢量几乎相互垂直，因此这种波在垂直方向上提供了有效的能量传递。因此，AGWs通过在垂直方向上重新分配水平风流的能量，对极地大气的能量平衡起着重要的作用。

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来源期刊

Kinematics and Physics of Celestial Bodies ASTRONOMY & ASTROPHYSICS-

CiteScore

0.90

自引率

40.00%

发文量

审稿时长

>12 weeks

期刊介绍： Kinematics and Physics of Celestial Bodies is an international peer reviewed journal that publishes original regular and review papers on positional and theoretical astronomy, Earth’s rotation and geodynamics, dynamics and physics of bodies of the Solar System, solar physics, physics of stars and interstellar medium, structure and dynamics of the Galaxy, extragalactic astronomy, atmospheric optics and astronomical climate, instruments and devices, and mathematical processing of astronomical information. The journal welcomes manuscripts from all countries in the English or Russian language.