The Influence of the Earth’s Atmosphere Rotation on the Spectrum of Acoustic-Gravity Waves

Abstract

It was shown in a recent study [11] that taking into account the rotation of the Earth’s atmosphere leads to the appearance of a new region of evanescent waves with a continuous frequency spectrum on the diagnostic diagram of acoustic-gravity waves. The region is located below the lower limit of gravity waves, which is equal to \(2\Omega \) for all wavelengths, where \(\Omega \) is the angular frequency of the atmospheric rotation. This result was obtained for high-latitude regions of the atmosphere in which one can be limited to considering only the vertical component of the Earth’s rotation frequency. This paper shows that taking into account both components of the vector \(\vec {\Omega }\) of the atmospheric rotation frequency \(\vec {\Omega }\)—horizontal, \(\Omega \cos \varphi ,\) where \(\varphi \) is the local latitude, and vertical, \(\Omega \sin \varphi \)—the dominant role in the acoustic-gravity wave propagation is played by the vertical component. It is shown that the horizontal component leads to a negligible modification of the boundaries of the regions of acoustic and gravity waves on the diagnostic diagram. It is also shown that the vertical component of the frequency affects most strongly the lower limit of gravity waves, which depends on the latitude of the observation site for all wavelengths and is equal to 2\(\Omega \sin \varphi \).