Eddy covariance measurements of the sea spray aerosol flux over the open ocean

Abstract

Direct eddy covariance measurements of size‐segregated sea spray aerosol fluxes over the open Atlantic Ocean are presented, along with a source function derived from them for a wind speed range of 4 to 18 m s −1 and a size range of 0.176 < R 80 < 6.61 μ m. This is in broad agreement with other recent estimates of the source function over this size range but shows a more rapid decrease with size above R 80 = 2 μ m than most other functions. The measurements were made during a 3 week cruise in the North Atlantic as part of the UK contribution to the international Surface Ocean–Lower Atmosphere Study (SOLAS) program. They utilized the new high‐rate Compact Lightweight Aerosol Spectrometer Probe (CLASP), providing a 16‐channel size spectrum (0.17 < R amb < 9.5 μ m) at 10 Hz, collocated with a sonic anemometer. The measurements demonstrate the high variability in sea spray aerosol flux compared with other air‐sea fluxes, both between individual estimates and in the scales contributing to the flux.