Maritime-continental drizzle contrasts in small cumuli

Continuous aircraft measurements of cloud condensation nuclei (CCN) were ma de during 16 summertime flights in eastern Florida. The air masses were div isible into maritime and continental regimes that respectively corresponded to wind direction-easterly (onshore) and westerly (offshore). Throughout t hese small cumulus clouds there were consistently higher concentrations of smaller droplets in the continental air. There was much more drizzle (diame ter > 50 mum) in the maritime clouds where drizzle was associated with larg er mean cloud droplet (2-50-mum diameter) sizes, higher concentrations of l arge cloud droplets, and greater amounts of cloud droplet liquid water. An apparent cloud droplet mean size threshold for the onset of drizzle was alm ost never exceeded in the continental clouds but was often exceeded in the maritime clouds, especially at higher altitudes. All together these results demonstrate that higher CCN concentrations suppressed drizzle.