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

By Dave Fritts, S. Vadas. 2008

140 citations recorded by the source corpus.

We previously considered various aspects of grav- ity wave penetration and effects at mesospheric and ther- mospheric 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 pen- etration altitudes depend on gravity wave phase speed, hor- izontal 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 fil- tering 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 wave- lengths 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 preferen- tial penetration of GWs that are up-shifted in frequency by thermospheric winds.

Subfields: Astronomy and Astrophysics, Atmospheric Science

View Paper: https://www.semanticscholar.org/paper/de63f87e15659ed7e44d7639f2573943258568b0

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In Astronomy and Astrophysics

1. Han-Li Liu
2. R. Akmaev
3. J. Oberheide
4. Liying Qian
5. G. Crowley
6. Astrid Maute
7. R. Roble
8. S. Solomon

In Atmospheric Science

1. Liying Qian
2. R. Garcia
3. S. Solomon
4. Han-Li Liu
5. F. Sassi
6. R. Akmaev
7. D. Marsh
8. Douglas E. Kinnison

Citations in the corpus

• WHOLE ATMOSPHERE MODELING: CONNECTING TERRESTRIAL AND SPACE WEATHER (2011, background): “Because of strong dissipation only high‐frequency (w ] wB) “tall” (m(2) ∼ k(2)) waves can penetrate to the F layer altitudes [Fritts and Vadas, 2008].”
• Generation of large-scale gravity waves and neutral winds in the thermosphere from the dissipation of convectively generated gravity waves (2009, unknown): “1986; Crowley et al., 1987; Fritts and Vadas, 2008 (hereinafter FV2008); Miyoshi and Fujiwara, 2008].”
• Thermosphere extension of the Whole Atmosphere Community Climate Model (2010, background): “The propagation of the secondary waves is influenced by the thermosphere temperature and wind (and thus the solar activity) [Vadas and Fritts, 2006], and can cause large”
• Sources of the traveling ionospheric disturbances observed by the ionospheric TIDDBIT sounder near Wallops Island on 30 October 2007 (2010, methodology): “All of the GWs have cH ≥ 140 m s−1 and lH ≥ 100 km, in excellent agreement with GW dissipative theory at these altitudes [V07; Fritts and Vadas, 2008].”