Comparison of Relationships between Aerosol Size Distributions and Cloud Supersaturations over the North Atlantic Ocean (Invited)

In regions where aerosol sources are limited and boundary layer clouds are frequent, the aerosol size distributions are affected by and have effects on the supersaturations of the clouds that activate and process them. Here we compare the relationships between aerosol size distributions and cloud supersaturations from the northern to southern ends of the North Atlantic Ocean, using data sets from the North Atlantic Aerosol and Marine Ecosystem Study (NAAMES), the Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE), and the Layered Aerosol Smoke Interactions with Cloud (LASIC) campaign. The Hoppel minima and the accumulation mode number concentrations were retrieved from the size distributions to show the average signatures of ensembles of air parcels processed by clouds. From the Hoppel minimum and the particle composition, the effective cloud supersaturation were estimated. In some regions with little variability in composition, the correlation of the supersaturation and the accumulation-mode aerosol shows a feedback effect of aerosols on clouds. In other regions, changes in cloud supersaturation were linked to differences in particle composition. Together these observations provide region-specific evidence of aerosol-cloud interactions.