IAA Seminar this Thursday
Seminarios IAA
IAA Seminar Series
Date: Thursday, 14 May, 12:30 CEST
Place: Salón de Actos
GCM simulations of ice giants and mini-neptunes: an overview of our understanding of the atmospheric dynamics of these planets
Ice giants and Mini-Neptunes have a thick gaseous envelope dominated by hydrogen and helium, enriched deep within with large amounts of water, methane or other volatile compounds. Uranus and Neptune are the only known planets of this type in our solar system and can serve as a laboratory for studying this type of atmosphere.
The Voyager-2 spacecraft, followed by numerous studies on large ground-based telescopes and the Hubble Space Telescope, revealed intense jet streams and meteorological activity on these planets. Indeed, the fastest zonal tropospheric winds in the solar system are found on Neptune (-400 m/s), while storm activity on both planets is no match for the gas giant planets. Despite these scientific motivations and advances in observational techniques, the atmospheric dynamics of these planets remain very little known. To date, global climate models (GCM) have never been able to reproduce zonal winds. The simulated winds were a factor of 10 to 100 lower than those observed.
The difficulties encountered in modelling atmospheric circulation on ice giants call into question the validity of the atmospheric circulation of mini-neptunes simulated to date by GCMs. The approximations to the primitive atmospheric equations used for the atmospheres of terrestrial planets (Earth, Mars, ...) may no longer be valid in the case of H2-dominated atmospheres. In this talk, we will attempt to explain the advances that have been made in understanding the atmospheric dynamics of this type of atmosphere by exploring the validity of various dynamic hypotheses.