Sea-spray aerosol particles generated in the surf zone.
Résumé
To assess the properties of aerosol particles generated over the surf zone, two experiments were held at the pier of Scripps Institution of Oceanography (SIO), La Jolla CA, and at the pier of the U.S. Army Corps of Engineers Field Research Facility (FRF) in Duck NC. On both sites concentrations of surf?generated sea spray particles, wave parameters and meteorological conditions were measured. The surf?aerosol concentrations in the diameter range 0.2–10 microns were obtained from the difference in aerosol size distributions measured upwind and downwind of the surf zone. It was found that the flux of surf?generated particles at diameters at formation can be expressed in terms of wave energy dissipation, which itself is related to the properties of the incoming wavefield and the bathymetry of the beach. Although the flux can also bemodeled in terms of wind speed, this relation is considered to be not universal and limited to low? to medium wind speeds. In Duck NC, two transport experiments were performed under offshore flow conditions. In this case, the surf?aerosol concentrations were obtained from the differences in three aerosol size distributions, measured just before and just behind the surf zone and up to 16 km downwind (out to sea). No significant decrease in concentration was observed at the farthest range, which suggests that an appreciable amount of surf?generated aerosols is advected over tens of kilometers.
Origine : Fichiers éditeurs autorisés sur une archive ouverte