Wave activity in and below Venusian clouds with the IPSL Venus GCM

Recent analyses mostly based on Akatsuki datasets brought many observational informations about the planetary-scale waves (Imai et al., 2019; Kajiwara et al., 2021) and thermal tides (Scarica et al., 2019, Akiba et al., 2021) at the top of the Venusian cloud layer. Further analysis of these data has enabled to build a view of the angular momentum balance at the cloud top, as a component of our understanding of superrotation (Horinouchi et al., 2020).

To help interpret and understand these wave activities and their impact on the angular momentum budget both in and below the cloud layer, the Venus Global Climate Model (GCM) we are developing at Institut Pierre-Simon Laplace (IPSL) is used in its latest configuration. Similarly to what was done with earlier configurations (Lebonnois et al., 2016), waves are extracted from the simulations to analyze (i) the thermal tide components, (ii) the dominant planetary-scale waves present in the cloud layer, Kelvin- and Rossby-type waves with periods close to 4-6 Earth days, and (iii) wave activity occurring in the deep atmosphere, below the cloud, corresponding to large-scale inertio-gravity waves. These different waves will be compared to observations to assess how the IPSL Venus GCM reproduces observational constraints. Angular momentum budget as evaluated in the GCM simulations will be discussed, with emphasis on the cloud top region.

References:

Akiba M. et al. (2021), JGR Planets 126, doi:10.1029/2020JE006808

Horinouchi T. et al. (2020), Science 368, 405–409, doi:10.1126/science.aaz4439

Imai M. et al. (2019), JGR Planets 124, doi:10.1029/2019JE006065

Kajiwara N. et al. (2021), JGR Planets 126, doi:10.1029/2021JE007047

Lebonnois S et al. (2016), Icarus 278, 38-51, doi:10.1016/j.icarus.2016.06.004

Scarica P. et al. (2019), Atmosphere 10, 584, doi:10.3390/atmos10100584