Physics
Scientific paper
Sep 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006jgra..11110s12v&link_type=abstract
Journal of Geophysical Research, Volume 111, Issue A10, CiteID A10S12
Physics
25
Atmospheric Processes: Thermospheric Dynamics (0358), Atmospheric Processes: Theoretical Modeling, Atmospheric Composition And Structure: Thermosphere: Energy Deposition (3369), Ionosphere: Ionospheric Disturbances
Scientific paper
We investigate the role convection plays in the thermosphere using deep convection and ray trace models with a general dissipative anelastic GW dispersion relation. In the absence of dissipation, a GW's vertical wavelength λz increases by $\sqrt{\overline {T}/\overline {T}0, or greater if its intrinsic frequency ωIr is close to the smaller thermospheric buoyancy frequency N = $\sqrt{\overline {T}0/\overline {T} N0. Here, $\overline {T and $\overline {T0 are the asymptotic temperatures in the thermosphere and lower atmosphere, respectively, and N0 is the buoyancy frequency in the lower atmosphere. In the presence of dissipation, λz also increases in the thermosphere by a factor of ~2-3 when ωIr > 0.2N0 and λz > 25 km during active solar conditions. GW dissipation altitudes and maximum vertical wavelengths, which increase as $\overline {T increases, are displayed for small-scale and midscale GWs. GWs excited from deep convection encounter horizontal shears, which impose anisotropy on the spectrum. Along with dissipative filtering, momentum flux divergence and body forces result. The thermospheric body forces resulting from our convection model achieve maximum accelerations at z $\simeq$ 180-200 km, extend down to z $\simeq$ 130 km, last for the duration of deep convection, are ~600 km × 600 km × 40-80 km in the x, y, and z directions, and are very strong with accelerations $\simeq$0.5-0.75 m s-2 and $\simeq$0.25-0.4 m s-2 during extreme solar minimum ($\overline {T = 600 K) and active solar conditions ($\overline {T = 2000 K), respectively. During extreme solar minimum, there is negligible forcing above z $\simeq$ 230 km, whereas the forcing extends up to z $\simeq$ 360 km during active solar conditions. These horizontal, thermospheric body forces may be a new source of large-scale, long-period secondary GWs and induced TIDs (traveling ionospheric disturbances) at high altitudes in the thermposphere.
Fritts David C.
Vadas Sharon L.
No associations
LandOfFree
Influence of solar variability on gravity wave structure and dissipation in the thermosphere from tropospheric convection does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Influence of solar variability on gravity wave structure and dissipation in the thermosphere from tropospheric convection, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Influence of solar variability on gravity wave structure and dissipation in the thermosphere from tropospheric convection will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-779672