Examining the Continuum between Cumuliform and Stratiform Boundary Layer Clouds Using Aircraft and Ship Observations over the North Atlantic

Low clouds over the ocean are recognized as an important contributor to uncertainty in the climate system. Changes in cloud fraction and albedo driven by changes in the environment (e.g. SST, static stability, humidity, aerosols) give rise to important cloud-radiation feedbacks that influence the climate. The mid-latitude oceans host a range of low-cloud types (fog, stratus, stratocumulus, cumulus) that often coexist within airmasses, and whose accurate representation in models is challenging. We examine the low cloud morphology and microphysical properties together with the boundary layer structure observed during the North Atlantic Aerosol and Marine Ecosystem Study (NAAMES). During this multi-deployment field campaign, in situ and remote sensing observations were obtained through the combination of a ship-cruise that transected the central North Atlantic and reconnaissance aircraft flights that periodically sampled the mesoscale environment surrounding the ship. We present a portrait of the clouds sampled during NAAMES, with particular focus on the hybrid representation of clouds that exist between the idealized conceptual frameworks of the well-mixed stratocumulus/stratus layer and the cumulus-topped mixed layer.