The Influence Of Sea State On The Generation Of Sea Spray Aerosol During WAGES

The Waves Aerosol and Gas Exchange Study (WAGES) project aims to improve our understanding of the impact of waves on the exchange of CO2 at the air-sea interface, and on the generation of sea spray aerosol. For this project we installed a range of instrumentation on the British Antarctic Survey ship, the RRS James Clark Ross, including the AutoFlux autonomous direct flux measurement system mounted on the foremast to make measurements of turbulent air-sea fluxes of CO2, sea-spray aerosol, sensible and latent heat and momentum. These were combined with measurements of the forcing parameters including mean wind, wave state, and whitecap fraction. Measurements were made continuously for over 3 years, May 2010 to September 2013, from the Arctic to Antarctica with transects of the Atlantic Ocean in-between. 6 manned campaigns supplemented the continuous data set with in-situ measurements from a spar buoy which made measurements of wave breaking and whitecaps under a wide range of conditions (mean wind speeds up to 20 m s-1 and significant wave heights of 8 m and water temperature 0 to 27 °C). Here we focus on the direct eddy-covariance sea-spray aerosol flux measurements obtained during WAGES using a Compact Lightweight Aerosol Spectrometer Probe (CLASP). The CLASP provides a 16-channel aerosol size spectrum in the range 0.18 < R < 7.5 µm at 10 Hz, enabling fully size segregated aerosol fluxes to be determined. We evaluate our existing Reynolds number parameterisation of the sea spray source flux over a wider range of water temperatures and examine the influence of fetch.