HAL will be down for maintenance from Friday, June 10 at 4pm through Monday, June 13 at 9am. More information
Skip to Main content Skip to Navigation
Journal articles

Venus’ upper atmosphere revealed by a GCM: I. Structure and variability of the circulation

Abstract : A numerical simulation of the upper atmosphere of Venus is carried out with an improved version of the Institut Pierre-Simon Laplace (IPSL) full-physics Venus General Circulation Model (GCM). This simulation reveals the organization of the atmospheric circulation at an altitude above 80 km in unprecedented detail. Converging flow towards the antisolar point results in supersonic wind speeds and generates a shock-like feature past the terminator at altitudes above 110 km. This shock-like feature greatly decreases nightside thermospheric wind speeds, favoring atmospheric variability on a hourly timescale in the nightside of the thermosphere. A 5-day period Kelvin wave originating in the cloud deck is found to substantially impact the Venusian upper atmosphere circulation. As the Kelvin wave impacts the nightside, the poleward meridional circulation is enhanced. Consequently, recombined molecular oxygen is periodically ejected to high latitudes, explaining the characteristics of the various observations of oxygen nightglow at 1,27 µm. An analysis of the simulated 1,27µm oxygen nightglow shows that it is not necessarily a good tracer of the upper atmospheric dynamics, since contributions from chemical processes and vertical transport often prevail over horizontal transport. Moreover, dayside atomic oxygen abundances also vary periodically as the Kelvin wave momentarily decreases horizontal wind speeds and enhances atomic oxygen abundances, explaining the observations of EUV oxygen dayglow. Despite the nitrogen chemistry not being currently included in the IPSL Venus GCM, the apparent maximum NO nightglow shifted towards the morning terminator might be explained by the simulated structure of winds.
Document type :
Journal articles
Complete list of metadata

Contributor : Catherine Cardon Connect in order to contact the contributor
Submitted on : Wednesday, June 16, 2021 - 8:05:04 PM
Last modification on : Friday, April 1, 2022 - 3:46:18 AM


Publisher files allowed on an open archive


Distributed under a Creative Commons Attribution - NoDerivatives 4.0 International License



Thomas Navarro, Gabriella Gilli, Gerald Schubert, Sébastien Lebonnois, Franck Lefèvre, et al.. Venus’ upper atmosphere revealed by a GCM: I. Structure and variability of the circulation. Icarus, Elsevier, 2021, 366 (September), pp.114400. ⟨10.1016/j.icarus.2021.114400⟩. ⟨insu-03162299v2⟩



Record views


Files downloads