The ECMWF analyses and reanalyses provide a global coverage of the atmospheric gravity wave (GW) field with spatial resolutions that allow the model to explicitly resolve a significant portion of the GW spectrum. Furthermore, those analyses span over several decades, making possible the study of the interannual variability of the GW field. However, the realism of the simulated GW field in the ECMWF analyses still needs to be precisely evaluated before studying its variability. First, the authors use data collected during the Concordiasi stratospheric balloon campaign to validate the representation of GWs in the ECMWF analyses over Antarctica and the Southern Ocean in spring 2010. The authors first compare the balloonborne GW momentum fluxes with those in ECMWF analyses throughout the campaign and find a correct agreement of the geographical and seasonal patterns. However, the authors also note that ECMWF analyses generally underestimate the balloon fluxes by a factor of 5, which may be essentially due to the spatial truncation of the ECMWF model. Intermittency of wave activity in the analyses and observations are found comparable. These results are confirmed on two case studies dealing with orographic and nonorographic waves, which thus supports that the ECMWF analyses can be used to study the geographical and time distribution of GW momentum fluxes. Later, Second, once the GW field validated, some preleminary results on the interannual variability of the global GW momentum fluxes in the ERA-Interim reanalyses and their relation with the evolution of the sources are presented for the period 2000-2010.

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*email: vjewtou@lmd.ens.fr
*Preference: Oral