Climatology of gravity wave activity in the middle atmosphere as simulated by a whole atmosphere gravity wave parameterization in a GCM and as observed by SABER/TIMED.

Atmospheric gravity waves are generated globally in the lower atmosphere by various weather phenomena during all seasons. They can propagate upward, growing in amplitude and carrying energy and momentum to higher altitudes, where they increasingly dissipate due to nonlinear interactions and other external processes such as molecular diffusion and thermal conduction and ion friction, and significantly influence the general circulation of the middle and upper atmosphere. Here, we use a three-dimensional first-principle general circulation model (GCM), incorporating the nonlinear whole atmosphere gravity wave parameterization of Yiğit et al. (2008) to study the global propagation of gravity waves from their sources upward and the resulting wave climatology in the middle atmosphere. For this, we test various distributions of gravity wave source activity specified in an empirical way, as well as from direct measurements. Specifically, we use gravity wave activity data as measured by the SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument onboard NASA's TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite in order to constrain the input of GW sources in the parameterization and also to validate their distributions in the mesosphere.