9420721 Bandy The major objective of this research is to quantify the efficiencies for the conversion of dimethylsulfide (DMS) to its various gas phase oxidation products in a remote marine atmosphere. This information is fundamental to assessing the significance of DMS as a precursor for atmospheric aerosol in the marine environment. An enhanced understanding of this linkage will provide a basis for incorporating tropospheric aerosol into global climate models and thereby contribute to a reduction in the present large uncertainty in the calculated climate forcing due to atmospheric aerosols derived from marine sources of DMS. The experimental work plan is centered on the measurement of sulfur dioxide (SO2), DMS, and carbonyl sulfide (OCS) during the field portion of the Southern Hemisphere Marine Aerosol Characterization Experiment (ACE-1). A novel gas chromatograph/quadrupole mass spectrometer (GC/MS) system will be used on-board the NCAR C-130 aircraft platform to perform measurements of these sulfur-containing gases. This GC/MS instrumentation will measure these three sulfur analytes at a frequency of one sample every four to five minutes and with a minimum detectability of approximately one part-per-trillion (volume to volume). These researchers will combine their analytical data with other ACE-1 measurements to determine the mechanisms, rates, and efficiencies of the chemical processes that affect the formation, growth, distribution, and radiative effects of atmospheric aerosols derived from sulfur gas precursors.
