Continuous Growth of Droplet Size Variance due to Condensation in Turbulent Clouds
Nordita Astrophysics seminars
Wednesday 18 November 2015
to 14:30 at
Gaetano Sardina (MISU)
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 t1/2, 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.