Aerocenter Seminar: Nicholas Meskhidze

North Carolina State University

The number concentration, size distribution and chemical composition of natural aerosols (both from terrestrial and marine sources) were suggested to be one of the major uncertainties in model-predicted indirect radiative forcing. Due to their massive source regions underlying an atmosphere with low aerosol concentration, marine aerosols derived from sea spray and ocean emitted biogenic volatile organic compounds (BVOCs) are extremely important for the Earth’s radiative budget, regional air quality and biogeochemical cycling of elements.

In this presentation I will 1) discuss the factors that determine the organic enrichment of sea spray based on laboratory measurement of cloud condensation nuclei (CCN) distributions of aerosols generated from a bubble-bursting tank using artificial sea-water. New wind speed dependent size-resolved parameterization for the organic enrichment of sea spray and its implementation in regional and global models will also be reviewed; 2) report BVOC (i.e., isoprene, α- and β-pinene, d-limonene, etc.) emission rates for laboratory grown phytoplankton monocultures and ambient samples and estimate global marine biogenic trace gas emission rates using dynamic physically-based emission mechanism; iii) explore CALIPSO/AMSR-E - derived relationship between “clean marine” aerosol optical properties and ocean surface wind speed; and iv) using global climate model (CAM5 ) simulations explore the effects of marine BVOCs and organic carbon aerosol emissions on microphysical and radiative properties of shallow clouds.