Slantwise convection on fluid planets

Abstract

Slantwise convection should be ubiquitous in the atmospheres of rapidly rotating fluid planets. We argue that convectively adjusted lapse rates should be interpreted along constant angular momentum surfaces instead of lines parallel to the local gravity vector. Using Cassini wind observations of Jupiter and different lapse rates to construct toy atmospheres, we explore parcel paths in symmetrically stable and unstable weather layers by the numerically modeled insertion of negatively buoyant bubbles. Low-Richardson number atmospheres are very susceptible to transient symmetric instability upon local diabatic forcing, even outside of the tropics. We explore parcel paths in symmetrically stable and unstable weather layer environments, the latter by adding thermal bubbles to the weather layer. Parcels that cool in Jupiter's belt regions have particularly horizontal paths, with implications for jetward angular momentum fluxes. These considerations may be relevant to the interpretation of Juno's ongoing observations of Jupiter's weather layer.