Black Carbon Aerosols and Aerosol-Cloud Interactions over the Northeastern Pacific Ocean

DONGLI WANG, Bradley Ries, Minghao Han, Alexander B. MacDonald, Don Collins, Roya Bahreini, Patrick Chuang, Lisa Welp-Smith, Mikael Witte, Andrew Metcalf, Clemson University

     Abstract Number: 465
     Working Group: Aerosols, Clouds and Climate

Abstract
Black carbon (BC) aerosol is a potentially significant contributor to aerosol-cloud interactions. BC aerosol is highly absorbing and thus potentially exerts important influence on cloud microphysical and radiative properties. The northeastern Pacific Ocean, off the coast of Southern California (CA), is a natural laboratory where aerosols originating from the San Diego to Los Angeles corridor interact with persistent stratocumulus. This talk will characterize the nature of BC aerosols over this region and investigate the interactions between BC particles and the marine atmosphere, including the persistent cloud cover.

A suite of aerosol and cloud instruments onboard the Navy Twin Otter aircraft made observations near San Diego, CA in June 2023 as part of the SCILLA field campaign in coordination with the EPCAPE campaign. A Single Particle Soot Photometer (SP2) is employed as the primary measurement of BC aerosol, including its size and mixing state. A scanning mobility particle sizer (SMPS) is used to measure the total submicron aerosol size distributions. Other aerosol instrumentation is used to characterize composition and cloud condensation nuclei, and several instruments were toggled between an isokinetic inlet and counterflow virtual impactor (CVI) inlet. Various cloud probes characterize the cloud droplet number concentrations and size distributions. With these data, the impact of BC aerosol and its mixing state on aerosol-cloud interactions in the marine boundary layer and free troposphere can be investigated. Results from this study are compared to a prior field campaign conducted in the summer of 2018 near the Monterey Bay area. Detailed characterization and investigation will help to understand the connection between BC aerosol and cloud properties to evaluate their impact on the marine environment.