Discovery of cloud top ozone on Venus

Emmanuel Marcq (1) , Lucio Baggio (1) , Franck Lefèvre (1) , Aurélien Stolzenbach (1) , Franck Montmessin (1) , Denis Belyaev (2) , Oleg Korablev (2) , Jean-Loup Bertaux (1)

1 PLANETO - LATMOS
2 IKI - Space Research Institute of the Russian Academy of Sciences

After the first sporadic detections of an ozone (O₃₃ volume mixing ratio peaks in the 10 to 20 ppbv range, yielding observable column densities in the 0.1 to 0.5 Dobson units (DU), comparable to nominal values on Mars but much smaller than for Earth ( ∼ 300 DU). These measurements are supported by our 3D-photochemical model coupled with the LMD-IPSL GCM (Lebonnois et al., 2010), which indicates that the ozone layer identified by SPICAV results from downward transport of O₂ ( ∼ 50 ppmv) molecules over the poles by the mean meridional circulation. Our findings do not contradict previous upper limits ( < 2 ppmv) based on O2 measurements (Mills, 1999), since they were restricted to lower latitudes only.

Mots clés: Venus; atmosphere; Ultraviolet; observations; Atmospheres; composition

Domaines: Astrophysique [astro-ph]

Emmanuel Marcq, Lucio Baggio, Franck Lefèvre, Aurélien Stolzenbach, Franck Montmessin, et al.. Discovery of cloud top ozone on Venus. Icarus, 2019, 319, pp.491-498. ⟨10.1016/j.icarus.2018.10.006⟩. ⟨insu-01894023⟩