Global analysis of scintillation variance: Indication of gravity wave breaking in the polar winter upper stratosphere

Viktoria F. Sofieva (1) , Erkki Kyrölä (1) , Seppo Hassinen (1) , Leif Backman (1) , Johanna Tamminen (1) , Annika Seppälä (1) , Laura Thölix (1) , Alexandre S. Gurvich (2) , Valery Kan (2) , Francis Dalaudier (3) , Alain Hauchecorne (3) , Jean-Loup Bertaux (3) , Didier Fussen (4) , Filip Vanhellemont (4) , Odile Fanton d' Andon (5) , Gilbert Barrot (5) , Antoine Mangin (5) , Marielle Guirlet (5) , Thorsten Fehr (6) , Paul Snoeij (7) , Lidia Saavedra (6) , Rob Koopman (6) , Renaud Fraisse (8)

1 FMI - Finnish Meteorological Institute
2 IAP - A.M.Obukhov Institute of Atmospheric Physics
3 SA - Service d'aéronomie
4 BIRA-IASB - Belgian Institute for Space Aeronomy / Institut d'Aéronomie Spatiale de Belgique
5 ACRI-ST - Analytic and Computational Research, Inc. - Earth Sciences
6 ESRIN - European Space Research Institute
7 ESTEC - European Space Research and Technology Centre
8 Astrium [Toulouse]

Stellar scintillations observed through the Earth atmosphere are caused by air density irregularities generated mainly by internal gravity waves and turbulence. We present global analysis of scintillation variance in two seasons of year 2003 based on GOMOS/Envisat fast photometer measurements. Scintillation variance can serve as a qualitative indicator of intensity of small-scale processes in the stratosphere. Strong increase of scintillation variance at high latitudes in winter is observed. The maximum of scintillation variance can be associated with the polar night jet. The simplified spectral analysis has shown the transition of scintillation spectra toward small scales with altitude, which is probably related with turbulence appearing as a result of wave breaking. The breaking of gravity waves in the polar night jet seems to start in the upper stratosphere, a predicted, but not confirmed by observations before, feature. Weaker enhancements in tropics are also observed; they might be related to tropical convection.

Domaines: Physique Atmosphérique et Océanique [physics.ao-ph]

Viktoria F. Sofieva, Erkki Kyrölä, Seppo Hassinen, Leif Backman, Johanna Tamminen, et al.. Global analysis of scintillation variance: Indication of gravity wave breaking in the polar winter upper stratosphere. Geophysical Research Letters, 2007, 34, pp.L03812. ⟨10.1029/2006GL028132⟩. ⟨hal-00162013⟩