Abstract:
Dimethylsulphide (DMS) and sub-micron atmospheric particles are key components in the atmospheric sulphur cycle. DMS produced by biota in the oceans is thought to be the main source of atmospheric sulphur in the atmosphere over the southwest Pacific. Once in the atmosphere, DMS is oxidised, resulting in the formation of aerosol containing non-sea-salt sulphate and methanesulphonic acid. An
... understanding of this gas to particle conversion process is important as the particles produced act as cloud condensation nuclei (CCN) and it through CCN that the sulphur cycle has the potential to affect climate on a global scale via a cloud albedo feedback mechanism. We need to know the amounts of aerosol that are produced under various atmospheric conditions. This project proposed to measure the major atmospheric sulphur compounds found in the gas and aerosol phase in order to improve the understanding of the atmospheric sulphur cycle in a clean marine atmosphere. The concentration and properties of these components, along with meteorological information, were measured at the water's edge of McDonald Beach on the northwest coast of Ross Island for a period of eighteen days. This work was in conjunction with work carried out in New Zealand and by using these results; we are able to make direct comparisons of behaviour of the sulphur cycle in these two very different environments to gain an understanding of how climate itself affects the cycle. Meteorological data includes wind speed, temperature, relative humidity and solar radiation. Reduced sulphur gases in both air and water was analysed by gas chromatography. Sea water samples over a shallow depth profile and samples from melt pools were analysed for dissolved gas levels. Airborne concentration of aerosols was examined by ion chromatography and CCN concentrations were recorded every three seconds. 
