Preprints
https://doi.org/10.5194/acpd-7-13345-2007
https://doi.org/10.5194/acpd-7-13345-2007
12 Sep 2007
 | 12 Sep 2007
Status: this preprint was under review for the journal ACP. A revision for further review has not been submitted.

Primary marine aerosol emissions: size resolved eddy covariance measurements with estimates of the sea salt and organic carbon fractions

E. D. Nilsson, E. M. Mårtensson, J. S. Van Ekeren, G. de Leeuw, M. Moerman, and C. O'Dowd

Abstract. Primary marine aerosol fluxes were measured using eddy covariance (EC), a condensation particle counter (CPC) and an optical particle counter (OPC) with a heated inlet. The later was used to discriminate between sea salt and total aerosol. Measurements were made from the 25 m tower at the research station Mace Head at the Irish west coast, May to September 2002. The aerosol fluxes were dominated by upward fluxes, sea spray from bubble bursting at the ocean surface. The sea salt aerosol number emissions increased two orders of magnitude with declining diameter from 1 to 0.1 μm where it peaked at values of 105 to 107 particles m−2s−1. The sea salt emissions increased at all sizes in the wind range 4 to 22 ms−1, in consistency with a power function of the wind speed. The sea salt emission data were compared to three recent sub micrometer sea salt source parameterisations. The best agreement was with Mårtensson et al. (2003), which appear to apply from 0.1 to 1.1 μm diameters in temperate water (12°C) as well as tropical water (25°C). The total aerosol emissions were independent of the wind speed below 10 ms−1, but increased with the wind above 10 ms−1. The aerosol volume emissions were larger for the total aerosol than for the sea salt at all wind speeds, while the sea salt number emissions approached the total number emissions at 15 ms−1. It is speculated that this is caused by organic carbon in the surface water that is depleted at high wind speeds. The data are consistent with an internal aerosol mixture of sea salt, organic carbon and water. Using the aerosol model by Ellison et al. (1999) (a mono-layer of organic carbon surrounding a water-sea-salt brine) we show that the total and sea salt aerosol emissions are consistent. This predict that the organic carbon fraction increase with decreasing diameter from a few % at 1 μm over 50% at about 0.5 μm to about 90% at 0.1 μm, in consistency with simultaneous chemical data by Cavalli et al. (2004). The combined models of Mårtensson et al. (2003) and Ellison et al. (1999) reproduce the observed total aerosol emissions and offer an approach to model the organic sea spray fraction.

E. D. Nilsson, E. M. Mårtensson, J. S. Van Ekeren, G. de Leeuw, M. Moerman, and C. O'Dowd
 
Status: closed (peer review stopped)
Status: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
 
Status: closed (peer review stopped)
Status: closed (peer review stopped)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
Printer-friendly Version - Printer-friendly version Supplement - Supplement
E. D. Nilsson, E. M. Mårtensson, J. S. Van Ekeren, G. de Leeuw, M. Moerman, and C. O'Dowd
E. D. Nilsson, E. M. Mårtensson, J. S. Van Ekeren, G. de Leeuw, M. Moerman, and C. O'Dowd

Viewed

Total article views: 2,013 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
1,168 717 128 2,013 137 121
  • HTML: 1,168
  • PDF: 717
  • XML: 128
  • Total: 2,013
  • BibTeX: 137
  • EndNote: 121
Views and downloads (calculated since 01 Feb 2013)
Cumulative views and downloads (calculated since 01 Feb 2013)

Cited

Saved

Latest update: 18 Apr 2024
Download
Altmetrics