  Atmospheric gravity waves (GWs) are generated in the lower atmosphere by
various weather phenomena. They propagate upward, carry energy and momentum to
higher altitudes, and appreciably influence the general circulation upon
depositing them in the middle and upper atmosphere. We use a three-dimensional
first-principle general circulation model (GCM) with an implemented nonlinear
whole atmosphere GW parameterization to study the global climatology of wave
activity and produced effects at altitudes up to the upper thermosphere. The
numerical experiments were guided by the GW momentum fluxes and temperature
variances as measured in 2010 by the SABER (Sounding of the Atmosphere using
Broadband Emission Radiometry) instrument onboard NASA's TIMED (Thermosphere
Ionosphere Mesosphere Energetics Dynamics) satellite. This includes the
latitudinal dependence and magnitude of GW activity in the lower stratosphere
for the boreal summer season. The modeling results were compared to the SABER
temperature and total absolute momentum flux, and Upper Atmosphere Research
Satellite (UARS) data in the mesosphere and lower thermosphere. Simulations
suggest that, in order to reproduce the observed circulation and wave activity
in the middle atmosphere, smaller than the measured GW fluxes have to be used
at the source level in the lower atmosphere. This is because observations
contain a broader spectrum of GWs, while parameterizations capture only a
portion relevant to the middle and upper atmosphere dynamics. Accounting for
the latitudinal variations of the source appreciably improves simulations.

Space Physics;Earth and Planetary Astrophysics;Atmospheric and Oceanic Physics;Computational Physics;Fluid Dynamics