Observations of Cloud Microstructure at the Centimeter Scale

Abstract

Current conceptual models of the processes that modify the droplet spectrum in convective clouds starts with entrainment of environmental air followed by turbulent mixing of these parcels into progressively finer filaments. Thus, one would expect, for scales larger than those at which molecular diffusion predominates, cloud structures should be observed with very sharp transitions between parcels with differing histories. Recent advances in microphysical measurements allow exploration of these processes at centimeter scales. In the present work, observations from an aircraft-mounted forward-scattering spectrometer probe, modified for faster response than the conventional probes, are presented. Cloud structures with very sharp interfaces are reported to exist on the smallest observable scale. These observations are intended to provide input into current efforts to model the evolution of the droplet spectrum.