Relative contribution of submicron and supermicron particles to aerosol light scattering in the marine boundary layer

Abstract

[1] Measurements of the aerosol light scattering coefficient (s sp ) at a wavelength of l = 550 nm were conducted at a coastal atmospheric research station in the east Atlantic Ocean during June 1999. Size distribution measurements between diameters of 3 nm and 40 mm (at ambient humidity) were used to derive scattering coefficients from Mie theory. The calculated scattering coefficients were about a factor of 7.4 higher than the measured scattering coefficients. The discrepancy was explained by a reduced cutoff of the sampling system at particle diameters between 6 and 8 mm, dependent on wind speed. The calculated aerosol scattering was about 1 order of magnitude higher than previously reported measurements in the MBL and is attributed to supermicrometer particles at sizes d > 10 mm dominating aerosol scattering