Aerosol dynamics in the equatorial Pacific marine boundary layer: microphysics, diurnal cycles and entrainment

Abstract

The authors measured the size-resolved physicochemical properties of aerosol particles at Christmas Island in the equatorial Pacific. No evidence for new particle production was found in the marine boundary layer (MBL) and more than 95% of all particles were consistently larger than 0.02 μm diameter, indicating an aged aerosol. Results suggest that the number distribution for condensation nuclei and cloud condensation nuclei was maintained by a quasi-equilibrium between entrainment from sources aloft and processes in the MBL. This implies a replenishment timescale for nuclei of about 2 and 4 days for this region. -from Authors