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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.
Michael P. Hickey
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).
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
Michael P. Hickey
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 …