Commentary on cloud modelling and the mass accommodation coefficient of water

[摘要] The mass accommodation coefficient of water is a quantity forwhich different experimental techniques have yielded conflicting valuesin the range 0.04-1. From the viewpoint of cloud modelling, this is an unfortunatesituation, since the value of the mass accommodation coefficientaffects the model results, e.g. the number concentration of activatedcloud droplets. In this commentary we note that in cloud modelling, the primary quantityof interest is the droplet growth rate rather than the mass accommodation coefficient, andthat experimental investigations of droplet growth rates provide more direct verificationof cloud models than do measurements of the massaccommodation coefficient.Furthermore, we argue that the droplet growth rates calculated in cloud model studies areconsistent with experimental results obtained so far only if a mass accommodationcoefficient of unity is applied.

[学科分类] 大气科学