Laboratory simulations and parameterization of the primary marine aerosol production

A major source of the primary marine aerosol is the bursting of air bubbles produced by breaking waves. Several source parameterizations are available from the literature, usually limited to particles with a dry diameter D p > 1 μm. The objective of this work is to extend the current knowledge to submicrometer particles. Bubbles were generated in synthetic seawater using a sintered glass filter, with a size spectra that are only partly the same spectra as measured in the field. Bubble spectra, and size distributions of the resulting aerosol (0.020–20.0 μm D p ) of the resulting aerosol, were measured for different salinity, water temperature ( T w ), and bubble flux. The spectra show a minimum at ∼1 μm D p , which separates two modes, one at ∼0.1 μm, with the largest number of particles, and one at 2.5 μm D p . The modes show different behavior with the variation of salinity and water temperature. When the water temperature increases, the number concentration N p decreases for D p < 0.07 μm, whereas for D p > 0.35 μm, N p increases. The salinity effect suggests different droplet formation processes for droplets smaller and larger than 0.2 μm D p . The number of particles produced per size increment, time unit, and whitecap surface (Φ) is described as a linear function of T w and a polynomial function of D p . Combining Φ with the whitecap coverage fraction W (in percent), an expression results for the primary marine aerosol source flux dF 0 / d log D p = W Φ (m −2 s −1 ). The results are compared with other commonly used formulations as well as with recent field observations. Implications for aerosol‐induced effects on climate are discussed.