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Full-Text Articles in Physical Sciences and Mathematics
Acoustic Waves Generated By Gusty Flow Over Hilly Terrain, R. L. Walterscheid, Michael P. Hickey Ph.D.
Acoustic Waves Generated By Gusty Flow Over Hilly Terrain, R. L. Walterscheid, Michael P. Hickey Ph.D.
Publications
We examine the generation of acoustic waves by gusty flow over hilly terrain. We use simple theoretical models of the interaction between terrain and eddies and a linear model of acoustic-gravity wave propagation. The calculations presented here suggest that over a dense array of geographically extensive sources orographically generated vertically propagating acoustic waves can be a significant cause of thermospheric heating. This heating may account in good part for the thermospheric hot spot near the Andes reported by Meriwether et al. (1996, 1997).
Antiphase Oh And Oi Airglow Emissions Induced By A Short-Period Ducted Gravity Wave, Jonathan B. Snively, Victor P. Pasko
Antiphase Oh And Oi Airglow Emissions Induced By A Short-Period Ducted Gravity Wave, Jonathan B. Snively, Victor P. Pasko
Publications
"Numerical simulation of a ducted gravity wave event suggests that OH (8,3) and O(1S) 557.7 nm airglow emissions layers may exhibit opposite-phase intensities when perturbed by a short-period wave undergoing vertical reflection. This effect arises due to the time and temperature dependance of the OH excitation reaction, coupled with the linear polarization properties of vertically-standing waves."
Physical Processes In Acoustic Wave Heating Of The Thermosphere, G. Schubert, Michael P. Hickey Ph.D., R. L. Walterscheid
Physical Processes In Acoustic Wave Heating Of The Thermosphere, G. Schubert, Michael P. Hickey Ph.D., R. L. Walterscheid
Publications
Upward propagating acoustic waves heat the atmosphere at essentially all heights due to effects of viscous dissipation, sensible heat flux divergence, and Eulerian drift work. Acoustic wave-induced pressure gradient work provides a cooling effect at all heights, but this is overwhelmed by the heating processes. Eulerian drift work and wave-induced pressure gradient work dominate the energy balance, but they nearly cancel at most altitudes, leaving their difference, together with viscous dissipation and sensible heat flux divergence to heat the atmosphere. Acoustic waves are very different from gravity waves which cool the upper atmosphere through the effect of sensible heat flux …
A Full-Wave Investigation Of The Use Of A ‘‘Cancellation Factor’’ In Gravity Wave–Oh Airglow Interaction Studies, Michael P. Hickey Ph.D., Yonghui Yu
A Full-Wave Investigation Of The Use Of A ‘‘Cancellation Factor’’ In Gravity Wave–Oh Airglow Interaction Studies, Michael P. Hickey Ph.D., Yonghui Yu
Publications
Atmospheric gravity waves (GWs) perturb minor species involved in the chemical reactions of airglow emissions in the upper mesosphere and lower thermosphere. In order to determine gravity wave fluxes and the forcing effects of gravity waves on the mean state (which are proportional to the square of the wave amplitude), it is essential that the amplitude of airglow brightness fluctuation be related to the amplitude of major gas density fluctuation in a deterministic way. This has been achieved through detailed modeling combining gravity wave dynamics described using a full-wave model with the chemistry relevant to the airglow emission of interest. …