Temperature and Composition Dependence of Sea Spray Aerosol Production
Abstract
A discrepancy between laboratory and field-derived parameterizations for the dependence of sea spray aerosol (SSA) particle number concentrations (Np) and size distributions on water temperature (Tw) exists. Here, we address this discrepancy by quantifying the Tw-dependence of SSA production over the range -2-25°C for laboratory-generated particles using a marine aerosol reference tank (MART), a miniature MART (miniMART) and a plunging jet. Four water types were considered: NaCl water, reef salt (RS) water, filtered and autoclaved reef salt (FARS), and filtered but not autoclaved seawater (NASW). For NaCl, RS, and FARS water the Np exhibited a moderate, monotonic increase with Tw for all generation methods (sensitivity of 2.1 - 4.1% °C-1). This contrasts with some previous laboratory studies but is consistent with parameterizations derived from ambient observations. The reconciliation of laboratory results with these parameterizations supports their use in global models. The Tw-sensitivity also increased with particle size in the submicron size range. This indicates the fraction of primary SSA that can act as cloud condensation nuclei has a different sensitivity to Tw than the total particle number. The particle production for actual seawater (NASW) differed from the other water types, exhibiting complex, irreproducible behavior with no clear Tw dependence due most likely to biologically or physically driven temporal evolution of seawater composition. This suggests that variability in seawater composition may have as large an impact as temperature on actual SSA production. The dependence of particle production on the salt concentration of the water is also examined. We find that, with the exception of salt-free water, that the shape of the size distribution exhibits only a small dependence on the salt concentration. These observations provide new constraints and context for understanding the dependence of SSA production on water temperature and composition.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.A14B..05C
- Keywords:
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- 0305 Aerosols and particles;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0315 Biosphere/atmosphere interactions;
- ATMOSPHERIC COMPOSITION AND STRUCTUREDE: 0409 Bioavailability: chemical speciation and complexation;
- BIOGEOSCIENCESDE: 4801 Aerosols;
- OCEANOGRAPHY: BIOLOGICAL AND CHEMICAL