Can we improve the realism of gravity wave parameterizations by imposing sources at all altitudes in the atmosphere?
Résumé
A multiwave non-orographic gravity waves (GWs) scheme is adapted to represent waves
of small intrinsic phase speed, inertial waves, and wave emission from all altitudes. This
last change removes the launching altitude parameter, an arbitrary parameter systematically used in GW schemes. In offline calculations using reanalysis fields, these changes impose larger amplitude saturated waves everywhere in the middle atmosphere, which
produces more realistic GW vertical spectra than in previous configurations. The same
scheme, tested online in the Laboratoire de M ́et ́eorologie Dynamique Zoom (LMDz) gen-
eral circulation model, performs at least as well as the operational non-orographic GW scheme. Some modest benefits are seen, for instance, in the equatorial tilt with altitude of the winter jets in the middle atmosphere. Although the scheme includes the effects
of inertial waves, which are detected in the mesosphere by different observational plat-
forms, the configuration that gives a reasonable climatology in LMDz hinders their vertical propagation and limits their presence at mesospheric altitudes.
Domaines
Océan, Atmosphère
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