Laboratory simulations and parameterization of the primary marine aerosol production

Abstract

[1] 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 mm. 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 mm 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 mm D p , which separates two modes, one at $0.1 mm, with the largest number of particles, and one at 2.5 mm 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 mm, whereas for D p > 0.35 mm, N p increases. The salinity effect suggests different droplet formation processes for droplets smaller and larger than 0.2 mm D p . The number of particles produced per size increment, time unit, and whitecap surface (È) is described as a linear function of T w and a polynomial function of D p . Combining È with the whitecap coverage fraction W (in percent), an expression results for the primary marine aerosol source flux dF 0 /dlogD p = W È (m À2 s À1 ). 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.

Effect of soluble surfactant on bubble persistence and bubble‐produced aerosol particles

“…We do not believe that the deficit can be accounted for by the absence in this work of any particular type of particle potentially found in natural sea spray aerosols, such as small organic particles or microgels, since source fluxes measured above artificial seawaters are comparable to those measured above natural seawaters under similar bubbling conditions (OC = 0 mM curve in Figure 7) [Fuentes et al, 2010a;Martensson et al, 2003;Tyree et al, 2007].…”

“…[5] However, the theory fails to account for the even smaller sea spray particles observed in many recent laboratory and ambient studies [Clarke et al, 2006;Fuentes et al, 2010a;Hultin et al, 2010;Keene et al, 2007;Martensson et al, 2003;Modini et al, 2010;Russell and Singh, 2006;Sellegri et al, 2006;Tyree et al, 2007]. Specifically, there is little explanation for the dominant SSA accumulation mode centered at~0.1-0.2 mm dry particle diameter.…”

Aerosol climate feedback due to decadal increases in Southern Hemisphere wind speeds

“…The model has been shown to agree well with particle size distribution observations over the remote SH oceans [Spracklen et al, 2007] and to reproduce the seasonal cycle of CCN at Cape Grim, Tasmania [Korhonen et al, 2008]. The wind speed dependent sea spray flux was parameterised according to Mårtensson et al [2003] (20 nm -2 mm dry diameter) and Monahan et al [1986] (>2 mm). Recent studies suggest that a fraction of submicron sea spray may be organic, rather than pure salt.…”

A Marine Aerosol Reference Tank system as a breaking wave analogue for the production of foam and sea-spray aerosols

“…Several different methods have been used to generate surrogate marine aerosols within enclosed tanks including pressurized atomizers (Svenningsson et al, 2006;Riziq et al, 2007;Saul et al, 2006;McNeill et al, 2006;Braban et al, 2007;Niedermeier et al, 2008;Taketani et al, 2009), forcing air through glass filters or sintered materials (Cloke et al, 1991;Martensson et al, 2003;Sellegri et al, 2006;Keene et al, 2007;Tyree et al, 2007;Wise et al, 2009;Hultin et al, 2010;Fuentes et al, 2010) and by a plunging water jet (Cipriano and Blanchard, 1981;Sellegri et al, 2006;Facchini et al, 2008;Fuentes et al, 2010).…”