First estimate of global cloud drop concentrations
In a 2009 paper by Pringle et al. we compared a mechanistic calculation of global cloud drop concentrations with a prediction based on simpler empirical methods used in many climate models. The comparison highlights some very large differences between the two approaches. The error is as much as 25–75% in the Southern Ocean, the Arctic and regions of persistent stratocumulus. These regions produce much higher CDN concentrations (for a given aerosol number) than predicted by the globally uniform empirical relations.
Empirical relations have had their day…