Turbulent, Non-Continuum Collision Growth Across the Cloud Droplet Size-Gap
A Monte Carlo model of warm-rain initiation that evolves a droplet population inside an adiabatically rising air parcel, coupling turbulent-shear and differential-sedimentation collisions with non-continuum (mean-free-path-dependent) hydrodynamic lubrication interactions and turbulence-induced supersaturation fluctuations, to explain how droplets cross the 15-40 micron radius 'size-gap' toward drizzle. It shows that collision growth beyond the condensation regime is highly sensitive to non-continuum effects, and that coupled turbulent-shear and gravitational collisions together with vapour-fluctuation-maintained polydispersity drive the crossing.
Generated using the official AMS LATEX template v6.1 The effect of turbulence, gravity, and
Micron-sized cloud droplets face a growth bottleneck in the 15-40 micron radius 'size-gap', where condensation and differential sedimentation are both weak at promoting growth. This study evolves a p…