Decoupling atmospheric and oceanic factors affecting aerosol loading over a cluster of mesoscale North Atlantic eddies

Using shipboard and satellite measurements we explore the environmental factors affecting the number concentration of aerosols with diameter 100<D<1000nm over a cluster of three mesoscale (~10-100km) eddies in the North Atlantic. Strongest sensitivity to environmental conditions was found in the 400<D<1000nm size range. In this size range particle concentrations were closely linked to the surface wind speed, indicating in situ production of sea spray aerosols by wind-driven processes. Particle concentrations were also affected by mesoscale variability in oceanic conditions at the vicinity of an anticyclonic eddy. In addition, a distinct aerosol population possibly produced at a distance of ~1000-2000km from the study area was identified. The results highlight the importance of oceanic and atmospheric mesoscale processes in determining the characteristics of aerosols over the marine environment.