Journal Article

PreJuSER-17008

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Implications for atmospheric dynamics derived from global observations of gravity wave momentum flux in strato- and mesosphere

Ern, M.FZJ* ; Preusse, P.FZJ* ; Gille, J. C. ; Hepplewhite, C. L. ; Mlynczak, M. G. ; Russell, J. M. I. ; Riese, M.FZJ*

2011
Union Washington, DC

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Please use a persistent id in citations: http://hdl.handle.net/2128/20917  doi:10.1029/2011JD015821

Abstract: In this work absolute values of gravity wave (GW) momentum flux are derived from global temperature measurements by the satellite instruments High Resolution Dynamics Limb Sounder (HIRDLS) and Sounding of the Atmosphere using Broadband Emission Radiometry (SABER). Momentum fluxes in the stratosphere are derived for both instruments and for SABER in the whole mesosphere. The large-scale atmospheric background state is removed by a two-dimensional Fourier decomposition in longitude and time, covering even planetary-scale waves with periods as short as 1-2 days. Therefore, it is possible to provide global distributions of GW momentum flux from observations for the first time in the mesosphere. Seasonal as well as longer-term variations of the global momentum flux distribution are discussed. GWs likely contribute significantly to the equatorward tilt of the polar night jet and to the poleward tilt of the summertime mesospheric jet. Our results suggest that GWs can undergo large latitudinal shifts while propagating upward. In particular, GWs generated by deep convection in the subtropical monsoon regions probably contribute significantly to the mesospheric summertime wind reversal at mid-and high latitudes. Variations in the GW longitudinal distribution caused by those convectively generated GWs are still observed in the mesosphere and could be important for the generation of the quasi two-day wave. Indications for quasi-biennial oscillation (QBO) induced variations of GW momentum flux are found in the subtropics. Also variations at time scales of about one 11-year solar cycle are observed and might indicate a negative correlation between solar flux and GW momentum flux.

Keyword(s): J

Note: Very helpful comments by three anonymous reviewers are gratefully acknowledged. The work of M. Ern was supported by the Deutsche Forschungsgemeinschaft (DFG) within the project GW-EXCITES (grant ER 474/2-1), which is part of the DFG priority program CAWSES (SPP-1176). This work further largely benefited from the SPARC gravity wave initiative, as well as "The Gravity Wave Project" (ISSI Team 161) led by M.J. Alexander and organized by the International Space Science Institute (ISSI), Bern. The SPARC zonal wind climatology was provided by the SPARC data center. Monthly Singapore winds were obtained from Free University of Berlin and monthly solar flux data from NOAA. SABER data were provided by GATS Inc., and HIRDLS data by NASA. Many thanks also go to the teams of the HIRDLS and SABER instruments for all their effort to create the excellent data sets used in this study.

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Contributing Institute(s):

1. Stratosphäre (IEK-7)

Research Program(s):

1. Atmosphäre und Klima (P23)

Appears in the scientific report 2011

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