SULFUR-DIOXIDE AND DIMETHYL SULFIDE IN THE CENTRAL PACIFIC TROPOSPHERE

Boundary-layer and free-troposphere measurements of sulfur dioxide, dimethyl sulfide, and carbon disulfide were made during transits of the central and southern Pacific Ocean between Hawaii and Australia. Sulfur dioxide was generally less than 100 pptv and highly variable with no correlation with respect to geographic location or altitude. Dimethyl sulfide in the boundary layer had a concentration range of <10 to 200 pptv. Highest concentrations of DMS were in the equatorial region of the southern hemisphere although the concentrations were dependent on location and meteorological regime. In the region of the Fiji Islands several boundary layer samples had SO2, DMS, and CS2. In 1989, additional SO2 measurements were made between Hawaii and the equator and to the west of Hawaii downwind of the Kilauea volcano plumes.