uniquely constrained by the data constitutes a debate beyond the scope of this study.

The relative scarcity of observational data for clouds in extraterrestrial atmospheres is far less constraining. Leading uncertainties include the characteristics of atmospheric dynamics and the populations of nuclei upon which cloud droplets form. Hence, we consider it appropriate to model extraterrestrial clouds using much simpler treatments.

Perhaps the simplest approach to modeling clouds is through a Lagrangian parcel model, in which the base of a cloud appears where the adiabatic cooling of an air parcel in an updraft results in saturation (ignoring any supersaturation associated with barriers to cloud droplet formation). Further cooling condenses vapor in excess of saturation onto cloud particles. The particles grow through condensation and coalescence until their sedimentation velocities exceed the updraft speed, and then fall out of the parcel. A number of problems arise in the formulation of updraft parcel models, among them: ignoring parcels in downdrafts, treating the mixing between parcels, treating the source of condensates into a parcel due to sedimentation from above, and determining updraft speeds.

Another simple approach, which we employ here, is through a one-dimensional Eulerian framework, in which turbulent diffusion mixes a condensable vapor upwards, 