Turbulent Entrainment and Mixing in Clouds: A New Observational Approach

Abstract

A statistical analysis of cloud droplet interarrival times, measured using an aircraft-mounted forward-scattering spectrometer probe, is used to deduce spatial scales of inhomogeneity of droplet concentration in cumulus clouds. The analysis often indicates inhomogeneity of the droplet concentration at small scales (about 1 cm) within regions that appear homogeneous when viewed at larger scales. An explanation of the small-scale inhomogeneity is offered, and the larger-scale homogeneity of the droplet concentration is interpreted in terms of the processes of entrainment and mixing.