Keywords: aerosols, atmospheric boundary layer, dimethyl sulphide emissions, marine atmosphere, modelling, radiation, simulation, DMS, surface water, marine conditions
Modelling the influence of dimethyl sulphide on aerosol production in the marine boundary layer
It has been postulated that dimethyl sulphide (DMS) emissions from the oceans can produce new condensation nuclei and eventually cloud condensation nuclei. Thus, DMS may have a significant influence on the Earth's radiation budget. A study of this postulate has been conducted for marine boundary layer conditions using a newly developed chemistry–aerosol–cloud (CAC) modelling system. The CAC modelling system is a variable heterogeneous chemistry model including aerosol physics using the modal concept. A series of simulations describing the clean marine atmosphere with variations of DMS emissions are presented. These simulations show that DMS can increase the particle number concentration of non sea-salt sulphate in accumulation mode from 10% to 25% under clean marine atmospheric conditions, and the total production of accumulation mode particles from 5% to 15%. Furthermore, the importance of including a DMS loss to the liquid-phase aerosols is shown. If this link is not included then the number of particles in the accumulation mode can be increased by a factor up to 8.