Quantitative assessment of surf-produced sea spray aerosol

The first results are presented from a quantitative model describing the aerosol production in the surf zone. A comparison is made with aerosol produced in the surf zone as measured during EOPACE experiments in La Jolla and Monterey. The surf aerosol production was derived from aerosol concentration gradients measured downwind from the surf zone, after correction for the background size distribution that was measured upwind from the wave breaking zone. The aerosol production model was originally developed from measurements performed along the Baltic coast(1). The model predicts the aerosol production from the total energy dissipated in the wave breaking zone, calculated from the coastal bathymetry and deep-water surface wave field. In the present work, the parameterisation of the aerosol production in the wave breaking zone is maintained, but the energy dissipation in the wave breaking zone is calculated using a different model that produces more realistic surf zone widths. Wave data were obtained from buoys off the Californian coast, while bathymetry data were supplied by the Scripps Institute of Oceanography. Observed and predicted aerosol production in the surf zone are in good agreement, for both sites. The predicted aerosol flux reproduces the day-to-day variations and even some of the observed variations on a time scale of several hours.