TY - JOUR

T1 - Approximation of vertical short waves of small amplitude in the atmosphere taking into account the average wind

AU - Кшевецкий, Сергей Петрович

AU - Курдяева, Юлия Андреевна

AU - Гаврилов, Николай Михайлович

N1 - Kshevetskii, S.P., Kurdyaeva, Y.A. & Gavrilov, N.M. Approximation of Vertical Short Waves of Small Amplitude in the Atmosphere Taking into Account the Average Wind. Izv. Atmos. Ocean. Phys. 59, 38–47 (2023). https://doi.org/10.1134/S0001433823010073

PY - 2023/9

Y1 - 2023/9

N2 - Using the method of different scales, formulas for the hydrodynamic fields of acoustic-gravity waves (AGWs) with vertical wavelengths that are small compared to the scales of changes in the background temperature and wind fields are derived. These formulas are equivalent to the conventional WKB approximation, but explicitly include the vertical gradients of the background fields. The conditions for the applicability of the formulas for describing the propagation of AGWs from the troposphere to the thermosphere are formulated and analyzed. The absence of singular points (critical levels) in the equations for wave modes in the analyzed height range is one of the conditions for the applicability of approximate formulas. For the wind from the empirical HWM model, singular points are often located below 200 km and are typical for internal gravity waves (IGWs) with lengths on the order of 10 km. As the wavelength increases, the number of singular points decreases. For IGWs with scales on the order of 300 km or more, there are usually no singular points. It is shown that IGWs with periods of less than 20 min propagating upward from tropospheric heights usually have one turning point in the altitude range from 100 to 130 km. The formulas are useful, in particular, for parametrizing the effects of AGWs in numerical models of atmospheric dynamics and energy.

AB - Using the method of different scales, formulas for the hydrodynamic fields of acoustic-gravity waves (AGWs) with vertical wavelengths that are small compared to the scales of changes in the background temperature and wind fields are derived. These formulas are equivalent to the conventional WKB approximation, but explicitly include the vertical gradients of the background fields. The conditions for the applicability of the formulas for describing the propagation of AGWs from the troposphere to the thermosphere are formulated and analyzed. The absence of singular points (critical levels) in the equations for wave modes in the analyzed height range is one of the conditions for the applicability of approximate formulas. For the wind from the empirical HWM model, singular points are often located below 200 km and are typical for internal gravity waves (IGWs) with lengths on the order of 10 km. As the wavelength increases, the number of singular points decreases. For IGWs with scales on the order of 300 km or more, there are usually no singular points. It is shown that IGWs with periods of less than 20 min propagating upward from tropospheric heights usually have one turning point in the altitude range from 100 to 130 km. The formulas are useful, in particular, for parametrizing the effects of AGWs in numerical models of atmospheric dynamics and energy.

KW - acoustic-gravity waves, shortwave approximation, WKB approximation, dispersion relation, critical level, singular point

KW - WKB approximation

KW - acoustic-gravity waves

KW - critical level

KW - dispersion relation

KW - shortwave approximation

KW - singular point

UR - https://www.mendeley.com/catalogue/71e80e9b-cfc4-39d8-842d-d03e7b1a1951/

U2 - 10.1134/s0001433823010073

DO - 10.1134/s0001433823010073

M3 - Article

VL - 59

SP - 38

EP - 47

JO - Izvestiya, Atmospheric and Oceanic Physics

JF - Izvestiya, Atmospheric and Oceanic Physics

SN - 0001-4338

IS - 1

ER -