期刊名称：Journal of Advances in Modeling Earth Systems
电子版ISSN：1942-2466
出版年度：2018
卷号：10
期号：11
页码：2777-2785
DOI：10.1029/2018MS001487
出版社：John Wiley & Sons, Ltd.
摘要：The dynamics and lifetime of atmospheric clouds are tightly coupled to entrainment and turbulent mixing. This paper presents direct numerical simulations of turbulent mixing followed by droplet evaporation at the cloud‐clear air interface in a meter‐sized volume, with an ensemble of up to almost half a billion individual cloud water droplets. The dependence of the mixing process on domain size reveals that inhomogeneous mixing becomes increasingly important as the domain size is increased. The shape of the droplet size distribution varies strongly with spatial scale, with the appearance of a pronounced negative exponential tail. The increase of relative dispersion during the transient mixing process is strongly dependent on the scale of the mixing and therefore on the Damköhler number, defined as the turbulence large‐eddy time scale divided by the cloud supersaturation relaxation time.
关键词：scale dependence;entrainment and mixing;microphysical response;mixing diagrams;droplet size distribution;relative dispersion
