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Effects of latitude-dependent gravity wave source variations on the middle and upper atmosphere
  • Erdal Yiğit,
  • Alexander S Medvedev,
  • Manfred Ern
Erdal Yiğit
George Mason University

Corresponding Author:[email protected]

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Alexander S Medvedev
Max Planck Institute for Solar System Research
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Manfred Ern
Forschungszentrum Jülich GmbH
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Atmospheric gravity waves (GWs) are generated globally in the lower atmosphere by various weather phenomena during all seasons. They propagate upward, carry a significant amount of energy and momentum to higher altitudes, and significantly influence the general circulation of 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 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 broad spectrum of GWs, while parameterizations capture only a portion relevant to the middle and upper atmosphere. Accounting for the latitudinal variations of the source appreciably improves simulations.