76 / 2024-09-06 09:27:19

Quantifying the contribution of primary marine organic aerosol

marine aerosol,hygroscopicity,marine organic aerosol

Session 25 - IGAC-SOLAS: Chemistry and physics at surface ocean and lower atmosphere

Marine primary organic aerosols (POA) are important component of marine climate system, regulating solar radiation budget and cloud dynamics. Despite their importance, there is a lack of extensive long-term observations, introducing great uncertainty in their parameterization in models. The lack of observation originated from the complexity of POA chemical compositions, very few long-term high resolution aerosol measurement of clean marine air, and the difficulty in performing source apportionment techniques over long term period. Utilizing a comprehensive high resolution time-of-flight aerosol mass spectrometer dataset spanning a decade (2009-2018), this study introduces a machine learning approach to differentiate and quantify the contribution of marine POA from marine secondary organic aerosol (SOA). Results indicate that marine POA maximized during summertime and minimized during winter. On average, marine POA constitutes 51% (21% to 76%) of the marine organic aerosol annually and up to 63% (48% to 75%) in summer. A better appreciation of marine POA is likely to improve the climate projections.