Fig. 6.

Schematic representation of stacked cells within an ice giant atmosphere. The equatorial retrograde jet is shown in orange and decays both above and below the clouds (Conrath et al. 1998; Tollefson et al. 2018). No eddy momentum fluxes are included here. The gradient in methane from equator to pole is shown as the thick blue arrow for $p>1$ bar, whereas the mid-latitude upwelling and equatorial/polar subsidence is shown for $p<1$ bar. Strong polar subsidence then explains the microwave brightness and NH₃/H₂S depletion. The variable thickness of a stable layer associated with water clouds is pure conjecture