Abstract
Abstract. Simultaneous measurements of near-surface aerosol (0.12 < R < 9.25 μm) and bubble spectra (13 < R < 620 μm) were made during five buoy deployments in the open ocean of the North Atlantic and used to estimate aerosol fluxes per unit area of whitecap. The measurements were made during two cruises as part of the Sea Spray, Gas Flux, and Whitecaps (SEASAW) project, a UK contribution to the international Surface Ocean Lower Atmosphere Study (SOLAS) program. The mean bubble number concentrations for each deployment are in broad agreement with other open ocean spectra and are consistently one to two orders of magnitude lower than surf zone studies. Production fluxes per unit area of whitecap are estimated from the mean aerosol concentration for each buoy deployment. They are found to increase with wind speed, and span the range of values found by previous laboratory and surf-zone studies for particles with radius at 80% relative humidity, R80 < 1 μm, but to drop off more rapidly with increasing particle size for larger particles. Estimates of the mean sea spray flux were made by scaling the whitecap production fluxes with in situ estimates of whitecap fraction. The sea spray fluxes are also compared with simultaneous individual eddy covariance flux estimates, and with a sea spray source function derived from them.
Highlights
Sea spray aerosol is an important component of the climate system and the largest single source of aerosol mass injected into the atmosphere after wind-blown dust (Hoppel et al, 2002)
This is comparable to the scale of the whitecaps; the excess aerosol measured within the concentration peak should be representative of those generated by the whitecap and it should be possible to isolate the spectrum produced by individual whitecaps occurring around the buoy from the mean background spectrum
Sea spray source fluxes have been estimated from joint in situ measurements of the aerosol produced by individual whitecaps and the fractional coverage of whitecaps in the open ocean of the North Atlantic
Summary
Sea spray aerosol is an important component of the climate system and the largest single source of aerosol mass injected into the atmosphere after wind-blown dust (Hoppel et al, 2002). To quantify the effects of sea spray aerosol on the environment, a detailed knowledge of the numbers and sizes of aerosol particles produced at the ocean surface is required. There are two production mechanisms for sea spray particles: mechanical tearing of water droplets (spume) from wave crests at high wind speeds, and the bursting of bubbles at the water surface. Leighton and Robb, 2008), gases coming out of solution as gas-saturated water warms (Norris et al, 2011), and where sea ice is present the release of bubbles Other potential production mechanisms for bubbles include production by the respiration of phytoplankton (Medwin, 1970; Johnson and Wangersky, 1987), release from the sea bed (e.g. Leighton and Robb, 2008), gases coming out of solution as gas-saturated water warms (Norris et al, 2011), and where sea ice is present the release of bubbles
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
