New project: Exploring natural aerosol formation from DMS oxidation and implications for aerosol forcing

Description

This poster describes a recently-initiated project on the formation of aerosol particles from dimethylsufide (DMS) oxidation, with a focus on project objectives and planned activities. The chemistry underlying the formation of a large fraction of natural aerosol – secondary sulfate produced by the oxidation of DMS – remains poorly constrained. In particular, the oxidation of DMS under pristine/pre-industrial (low NO) conditions is not well understood, nor is the aqueous phase chemsitry of DMS and its reaction products. Such processes are therefore generally neglected in most three-dimensional atmospheric chemistry models, leading to substantial uncertainty in estimates of the natural aerosol burden, and hence in estimates of present and future aerosol radiative forcing. We plan to target this critical gap in understanding the lifecycle and impacts of natural aerosols with a collaborative experimental and modeling project. The specific objectives of this project are: 1) To investigate and characterize the chemical formation of natural aerosol from DMS oxidation under a range of conditions, representative of both the pre-industrial era and present day. 2) To investigate how an improved characterization of the natural sulfate aerosol background impacts estimates of aerosol radiative forcing. Experimental results will be the basis for the development of a new model scheme, which will be implemented in the earth system models and tested against field measurements.