Comments on “Parameterization of the Autoconversion Process. Part I: Analytical Formulation of the Kessler-Type Parameterizations”

In a recent paper, Liu and Daum (2004, hereafter LD04) derive analytical expressions for the rate of au-toconversion of cloud droplets to embryonic raindrops for a range of assumptions about the dependence of the collection kernel upon cloud droplet size. Their analyti-cal derivations are used to provide a physical formalism for some of the autoconversion parameterizations that are widely used in a broad range of numerical models (e.g., Kessler 1969; Tripoli and Cotton 1980; Bake