PSI 1-3 (1989-1991)
The Pacific Sulfur-Stratus Investigation (PSI) was an interdisciplinary program utilizing ship, aircraft, satellite, and shore-based measurements, to describe the biological, chemical, and physical oceanography; atmospheric gas phase, condensed phase and cloud water chemistry; aerosol size distribution, cloud condensation nuclei population, cloud microphysics, cloud albedo, and meteorology. The goals of these experiments were to measure the concentration of the major sulfur species in both the surface ocean and as a function of altitude above the ocean, to begin quantifying the processes controlling these concentrations, and to develop an understanding of the relationships between the measured parameters. A major goal of PSI-3 was to study the cycling of sulfur in the upper water column.
There were three PSI field experiments (30 May to 10 June 1989, 2 to 27 April 1990, and 15 April to 1 May 1991) conducted along the coast of Washington State.