Articles | Volume 11, issue 16
Atmos. Chem. Phys., 11, 8777–8790, 2011
https://doi.org/10.5194/acp-11-8777-2011
Atmos. Chem. Phys., 11, 8777–8790, 2011
https://doi.org/10.5194/acp-11-8777-2011

Research article 30 Aug 2011

Research article | 30 Aug 2011

Wind speed dependent size-resolved parameterization for the organic mass fraction of sea spray aerosol

B. Gantt1, N. Meskhidze1, M. C. Facchini2, M. Rinaldi2, D. Ceburnis3, and C. D. O'Dowd3 B. Gantt et al.
  • 1North Carolina State University, Raleigh, NC, USA
  • 2Institute of Atmospheric Sciences and Climate (ISAC), National Research Council (CNR), Bologna, Italy
  • 3School of Physics and Centre for Climate and Air Pollution Studies, Ryan Institute, National University of Ireland Galway, University Road, Galway, Ireland

Abstract. For oceans to be a significant source of primary organic aerosol (POA), sea spray aerosol (SSA) must be highly enriched with organics relative to the bulk seawater. We propose that organic enrichment at the air-sea interface, chemical composition of seawater, and the aerosol size are three main parameters controlling the organic mass fraction of sea spray aerosol (OMSSA). To test this hypothesis, we developed a new marine POA emission function based on a conceptual relationship between the organic enrichment at the air-sea interface and surface wind speed. The resulting parameterization is explored using aerosol chemical composition and surface wind speed from Atlantic and Pacific coastal stations, and satellite-derived ocean concentrations of chlorophyll-a, dissolved organic carbon, and particulate organic carbon. Of all the parameters examined, a multi-variable logistic regression revealed that the combination of 10 m wind speed and surface chlorophyll-a concentration ([Chl-a]) are the most consistent predictors of OMSSA. This relationship, combined with the published aerosol size dependence of OMSSA, resulted in a new parameterization for the organic mass fraction of SSA. Global emissions of marine POA are investigated here by applying this newly-developed relationship to existing sea spray emission functions, satellite-derived [Chl-a], and modeled 10 m winds. Analysis of model simulations shows that global annual submicron marine organic emission associated with sea spray is estimated to be from 2.8 to 5.6 Tg C yr−1. This study provides additional evidence that marine primary organic aerosols are a globally significant source of organics in the atmosphere.

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