One of the outstanding problem areas in global tropospheric chemistry is the sulfur chemistry of the marine atmosphere. The University of Washington (UW) has embarked on a research program to address two important aspects of this problem: determination of the vertical distributions of sulfur species in marine air and the factors responsible for these distributions, and determination of the relationships between dimethylsulfide, sulfate, cloud condensation nuclei and cloud microstructures in marine air. In the past two years, the UW has developed, calibrated and field tested the instruments needed for field measurements. It has developed sampling protocols and analysis techniques, obtained preliminary field measurements, and begun numerical modeling studies. Topics to be studied include: relationship between dimethyl sulfide in seawater and the air, diurnal, seasonal and geographic variability of dimethyl sulfide concentrations, dimethyl sulfide oxidation, sulfur dioxide production, sulfur dioxide oxidation, MSA-sulfur dioxide branching, cloud pumping, sulfur dioxide to sulfate conversion in clouds and the dimethyl sulfide-climate hypotheses. The field studies will be carried out as part of the Pacific Sulfur/Stratus Investigation in the NE. In addition, seasonal variability will be explored through flights over the NE Pacific.
