Seminar: CPS/WTK Seminar
date: 2020 October 6 (Tue) 16:00 - 18:00
Room: Online seminar (Zoom + Video conference system)
Speaker: Takeshi Imamura (Professor, Graduate School of Frontier Sciences, The University of Tokyo)
Title: Superrotation in Planetary Atmospheres
Abstract: Atmospheric superrotation is a dynamical regime where the atmosphere circulates around the planet in the direction of planetary rotation with excess angular momentum in the equatorial region. Superrotation is known to exist in the atmospheres of Venus, Titan, Jupiter and Saturn in the solar system. Some of the exoplanets also exhibit superrotation. It has been shown theoretically that angular momentum transport by non-axisymmetric disturbances is necessary for super-rotation to be maintained. Numerical models suggest that angular momentum transport by global instability and thermal tides play key roles for the terrestrial planets. Recent gravity data at Jupiter and Saturn suggest that the superrotating flows extend deep into the planet, and currently no single mechanism has been identified. Tidally locked, strongly irradiated exoplanets are expected to have superrotating atmospheres. In this talk the characteristics of the observed superrotation and the possible mechanisms will be reviewed. The content will be based on Imamura et al. (2020):
Keywords: superrotation, planets
Organizer: Yoshi-Yuki Hayashi