title: Continuous Growth of Droplet Size Variance due to Condensation in Turbulent Clouds.
abstract: We use a stochastic model and direct numerical simulation to study the impact of turbulence on cloud droplet growth by condensation. We show that the variance of the droplet size distribution increases in time as t^{1/2}, with growth rate proportional to the large-to-small turbulent scale separation and to the turbulence integral scales but independent of the mean turbulent dissipation. Direct numerical simulations confirm this result and produce realistically broad droplet size spectra over time intervals of 20 min, comparable with the time of rain formation.
authors.affiliation: Department of Meteorology and SeRC, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Sardina
authors.affiliation: Linné FLOW Centre and SeRC, KTH Mechanics, SE-100 44 Stockholm, Sweden.|Department of Industrial Engineering, University of Padova, 35131 Padova, Italy.
authors.forename: Francesco
authors.initials: F
authors.lastname: Picano
authors.affiliation: Linné FLOW Centre and SeRC, KTH Mechanics, SE-100 44 Stockholm, Sweden.
authors.forename: Luca
authors.initials: L
authors.lastname: Brandt
authors.affiliation: Department of Meteorology and SeRC, Stockholm University, SE-106 91 Stockholm, Sweden.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Caballero