The viscous damping of atmospheric gravity waves

Pitteway, M. L. V.; Hines, C. O.

doi:10.1029/gm018p0363

Cited by 52 publications

(88 citation statements)

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“…Its can also be applied to the large-amplitude GWs after properly including a scheme to parameterize the effects of GW saturation and/or breaking (Marks and Eckermann, 1995;Vadas and Crowley, 2010;. It is important to note that the theoretical basis for ray tracing is the WKB (Wentzel-Kramers-Brillouin) method, which requires the variation of the background atmosphere to be slow relative to the GW vertical wavelength (Pitteway and Hines, 1963;Einaudi and Hines, 1970;Nappo, 2002). For example, in a constant-wind (dissipative) thermosphere, the slowly varying background assumption requires λ z ≤ 4πH (VF05; Vadas, 2007).…”

Section: Liu Et Al: the Momentum Deposition Of Small Amplitude Grmentioning

confidence: 99%

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Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Liu

Yue

et al. 2013

Ann. Geophys.

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Abstract. We study the momentum deposition in the thermosphere from the dissipation of small amplitude gravity waves (GWs) within a wave packet using a fully nonlinear two-dimensional compressible numerical model. The model solves the nonlinear propagation and dissipation of a GW packet from the stratosphere into the thermosphere with realistic molecular viscosity and thermal diffusivity for various Prandtl numbers. The numerical simulations are performed for GW packets with initial vertical wavelengths (λ z ) ranging from 5 to 50 km. We show that λ z decreases in time as a GW packet dissipates in the thermosphere, in agreement with the ray trace results of Vadas and Fritts (2005) (VF05). We also find good agreement for the peak height of the momentum flux (z diss ) between our simulations and VF05 for GWs with initial λ z ≤ 2πH in an isothermal, windless background, where H is the density scale height. We also confirm that z diss increases with increasing Prandtl number. We include eddy diffusion in the model, and find that the momentum deposition occurs at lower altitudes and has two separate peaks for GW packets with small initial λ z . We also simulate GW packets in a non-isothermal atmosphere. The net λ z profile is a competition between its decrease from viscosity and its increase from the increasing background temperature. We find that the wave packet disperses more in the non-isothermal atmosphere, and causes changes to the momentum flux and λ z spectra at both early and late times for GW packets with initial λ z ≥ 10 km. These effects are caused by the increase in T in the thermosphere, and the decrease in T near the mesopause.

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Section: Liu Et Al: the Momentum Deposition Of Small Amplitude Grmentioning

confidence: 99%

“…Only GWs with large λ z can propagate deep into the thermosphere ). Eventually, every GW dissipates in the thermosphere (Pitteway and Hines, 1963;Hines, 1973;Richmond, 1978;Hickey and Cole, 1988;Zhang and Yi, 2002;VF05;Walterscheid and Hickey, 2011;Vadas and Nicolls, 2012;Nicolls et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Liu

Yue

et al. 2013

Ann. Geophys.

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“…For instance, kinematic viscosity is often assumed to be constant in derivations of dispersion equations of atmospheric waves. [7][8][9][10][11] It is a dubious approach since the kinematic viscosity changes by 5 orders of magnitude between ground level and 200 km altitude. While the assumption of constant shear viscosity would be much more realistic, it does not lead to plane-wave solutions.…”

Section: Introductionmentioning

confidence: 99%

Dissipation of acoustic-gravity waves: An asymptotic approach

Godin

2014

The Journal of the Acoustical Society of America

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Acoustic-gravity waves in the middle and upper atmosphere and long-range propagation of infrasound are strongly affected by air viscosity and thermal conductivity. To characterize the wave dissipation, it is typical to consider idealized environments, which admit plane-wave solutions. Here, an asymptotic approach is developed that relies instead on the assumption that spatial variations of environmental parameters are gradual. It is found that realistic assumptions about the atmosphere lead to rather different predictions for wave damping than do the plane-wave solutions. A modification to the Sutherland-Bass model of infrasound absorption is proposed.

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“…This accounts for the "turbopause", which exhibits some variability in altitude that likely results from spatial and temporal variability in GW energy fluxes and propagation conditions. Early efforts to account for GW dissipation at higher altitudes accounted only partially for these damping effects (Pitteway and Hines, 1963;Yeh et al, 1975;Hickey and Cole, 1987). A more recent theory accounting for kinematic viscosity and thermal diffusivity and their variations with altitude assuming a localized, but temporally-varying, GW packet was advanced by Vadas and Fritts (2005, hereafter VF05).…”

Section: Introductionmentioning

confidence: 99%

Gravity wave penetration into the thermosphere: sensitivity to solar cycle variations and mean winds

2008

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Abstract. We previously considered various aspects of gravity wave penetration and effects at mesospheric and thermospheric altitudes, including propagation, viscous effects on wave structure, characteristics, and damping, local body forcing, responses to solar cycle temperature variations, and filtering by mean winds. Several of these efforts focused on gravity waves arising from deep convection or in situ body forcing accompanying wave dissipation. Here we generalize these results to a broad range of gravity wave phase speeds, spatial scales, and intrinsic frequencies in order to address all of the major gravity wave sources in the lower atmosphere potentially impacting the thermosphere. We show how penetration altitudes depend on gravity wave phase speed, horizontal and vertical wavelengths, and observed frequencies for a range of thermospheric temperatures spanning realistic solar conditions and winds spanning reasonable mean and tidal amplitudes. Our results emphasize that independent of gravity wave source, thermospheric temperature, and filtering conditions, those gravity waves that penetrate to the highest altitudes have increasing vertical wavelengths and decreasing intrinsic frequencies with increasing altitude. The spatial scales at the highest altitudes at which gravity wave perturbations are observed are inevitably horizontal wavelengths of ∼150 to 1000 km and vertical wavelengths of ∼150 to 500 km or more, with the larger horizontal scales only becoming important for the stronger Doppler-shifting conditions. Observed and intrinsic periods are typically ∼10 to 60 min and ∼10 to 30 min, respectively, with the intrinsic periods shorter at the highest altitudes because of preferential penetration of GWs that are up-shifted in frequency by thermospheric winds.

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The viscous damping of atmospheric gravity waves

Cited by 52 publications

References 0 publications

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Numerical modeling study of the momentum deposition of small amplitude gravity waves in the thermosphere

Dissipation of acoustic-gravity waves: An asymptotic approach

Gravity wave penetration into the thermosphere: sensitivity to solar cycle variations and mean winds

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