Local and global changes to the thermosphere from the dissipation of gravity waves from deep convection

Sharon Vadas*
NorthWest Research Associates

We discuss the global changes that occur in the thermosphere from the gravity waves (GWs) created by deep convection using 3 models. The convective objects are located from meteorology satellites. The first model calculates the idealized GW spectra excited by each convective object. The second model ray traces the GWs into thermosphere. The average momentum fluxes, wavevectors, and phases are saved on a grid in the ray trace model. Then the primary GW field in the thermosphere is reconstructed using the GW dissipative polarization relations. The thermospheric body forces and heat/coolings are calculated and are inputted into the third model, which is the global TIME-GCM. Secondary GWs are excited by these forces and heat/coolings. We examine deep convection globally over 13 day periods during 2000 and 2009. The most important global change is to the horizontal winds. These effects are largest at z~200-250 km (with values up to hundreds of m/s), but extend to z~400 km (with values of 50-100 m/s). There are also significant changes to the global temperature. The themospheric body forces are most important for creating global wind, temperature, and neutral density changes. Although the primary GWs from deep convection create the dominant effects in the thermosphere below z<250 km, the secondary GWs create the dominant effects above z>250 km.



*email: vasha@cora.nwra.com
*Preference: no preference