Observed and Simulated Variability of Droplet Spectral Dispersion in Convective Clouds Over the Amazon

In this study, the variability of the spectral dispersion of droplet size distributions (DSDs) in convective clouds is investigated. Analyses are based on aircraft measurements of growing cumuli near the Amazon basin, and on numerical simulations of an idealized ice‐free cumulus. In cleaner clouds, the relative dispersion ϵ, defined as the ratio of the standard deviation to the mean value of the droplet diameter, is negatively correlated with the ratio of the cloud water content (qc) to the adiabatic liquid water content (qa), while no strong correlation between ϵ and qc/qa is seen in polluted clouds. Bin microphysics numerical simulations suggest that these contrasting behaviors are associ…