Near-surface measurements of sea spray aerosol production over whitecaps in the open ocean

[摘要] Simultaneous measurements of near-surface aerosol (0.12 < R < 9.25 μm) and bubble spectra (13 < R < 620 μm) weremade during five buoy deployments in the open ocean of the North Atlanticand used to estimate aerosol fluxes per unit area of whitecap. Themeasurements were made during two cruises as part of the Sea Spray, Gas Flux, and Whitecaps (SEASAW) project, aUK contribution to the international Surface OceanLower Atmosphere Study (SOLAS) program. The mean bubble numberconcentrations for each deployment are in broad agreement with other openocean spectra and are consistently one to two orders of magnitude lower thansurf zone studies. Production fluxes per unit area of whitecap are estimatedfrom the mean aerosol concentration for each buoy deployment. They are foundto increase with wind speed, and span the range of values found by previouslaboratory and surf-zone studies for particles with radius at 80%relative humidity, R₈₀ < 1 μm, but to drop off more rapidlywith increasing particle size for larger particles. Estimates of the meansea spray flux were made by scaling the whitecap production fluxes within situ estimates of whitecap fraction. The sea spray fluxes are alsocompared with simultaneous individual eddy covariance flux estimates, andwith a sea spray source function derived from them.

[学科分类] 海洋学与技术