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Black Carbon Aerosol-Cloud Effects over the Eastern North Pacific Ocean
Nilima Sarwar, Dongli Wang, Walt Williams, Armin Sorooshian, Haflidi Jonsson, Richard Flagan, John Seinfeld, ANDREW METCALF, Clemson University
Abstract Number: 316
Working Group: Aerosols, Clouds and Climate
Abstract
Ambient data on atmospheric black carbon (BC) aerosol was collected near Monterey, California in an aircraft-based field campaign named the Marine Aerosol Cloud and Wildfire Study (MACAWS) in June and July of 2018. A Single-Particle Soot Photometer (SP2) was used to measure BC aerosol and its mixing state. During the collaborative field project, data were collected on BC and other aerosol particles from different types of sources, including emissions from open biomass burning, marine combustion engines, on-road diesel engines, and aerosol from long-range transport. Recent studies have found the marine environment is affected both directly and indirectly by BC aerosol.
In this talk, the influence of BC aerosol on the formation and properties of the marine boundary layer are assessed. The mass concentration, size distribution, and mixing state of BC aerosol particles are used to evaluate the different sources of BC aerosol and their influences on the marine stratocumulus layer. During the sampling campaign, we observed both clean and BC-perturbed clouds off the California coast. Major findings from this study include - observing an increase in average BC mass and number concentrations from the marine boundary layer to an above-cloud BC layer, pollution of clouds by entrainment of BC aerosols, and evidence of wet scavenging of BC by cloud droplets. Overall, the marine environment in this region is characterized by a complex mixture of marine engine exhaust, transported wildfire plumes, and long-range transported aerosol.