Magnitude of eddy diffusion in the water-condensation region

Determine the exact magnitude of the eddy diffusion coefficient K_{zz} in the water-condensation region of Uranus and Neptune, where convection inhibition, moist convection, precipitation, and planetary rotation may reduce vertical mixing by orders of magnitude.

Background

The inferred deep oxygen abundances depend strongly on the eddy diffusion coefficient K_{zz}. The paper applies a latitude-dependent prescription derived for convective regions, but notes that this prescription may not remain valid near the water-cloud base, where convection can be inhibited and K_{zz} may approach molecular diffusivity. Other cited studies predict substantially lower mixing efficiencies when precipitation and moist-convection processes are treated more realistically. Since the water-condensation region affects the transport and quenching of disequilibrium species, its unresolved K_{zz} magnitude is a major source of uncertainty in the inferred deep composition.