Atmospheric Dynamics of Giants and Icy Planets

This chapter deals with the state of knowledge of the dynamics of the atmospheres of the gas giants (Jupiter and Saturn) and ice giants (Uranus and Neptune), describing their general circulation, the most relevant atmospheric phenomena, and the models developed so far to explain their atmospheric dynamics. Observations show that these two types of fluid and cold planets differ in their general circulation at cloud level. Jupiter and Saturn are dominated by a jet system that alternates in their direction with latitude, and both possess an intense eastward equatorial jet. On the other hand, Uranus and Neptune show a dominating intense and wide in latitude westward jet symmetric with respect to the equator. In spite of this difference, the four planets present similar atmospheric dynamical phenomena (large-scale vortices, storms, and long waves, among others). Deep convection models have shown that turbulent convection resulting in angular momentum mixing may explain the westward (retrograde) equatorial flow on the ice giants. The jet systems of Jupiter and Saturn have been successfully reproduced using deep convection and shallow forcing models. However, the prograde equatorial flow of the gas giants is more naturally reproduced with deep models or hybrid shallow models incorporating aspects of deeper forcing.