Modelling the contribution of sea salt and dimethyl sulfide derived aerosol to marine CCN

[摘要] The concentration of cloud condensation nuclei (CCN) in the marineboundary layer (MBL) was estimated from dimethyl sulfide (DMS) flux, seasalt (SS)emission, and aerosols entrained from the free troposphere (FT). Only under clean airconditions, did the nucleation of DMS derived sulfur (DMS CCN) contribute significantly to the MBL CCN.The accommodation coefficient for sulfuric acid masstransfer was found to be a very important parameter in the modeling the contributionof DMS to MBL CCN.The relationship between seawater DMS and MBL CCN was found to be non-linear mainly due to the transfer processes of sulfuric acid ontoaerosols.In addition, sea salt derived CCN (SS CCN) and entrained aerosol from the FT(FT CCN) affected the MBL CCN directly, by supplying CCN, and indirectly, bybehaving as an efficient sink for sulfuric acid.The SS CCN explained more than50% of the total predicted MBL CCN when wind speeds were moderate and high.Sea saltand FT aerosol may often be more efficient sources of MBL CCN than DMS.

[学科分类] 大气科学