The Pacific Atmospheric Sulfur Experiment (PASE) is a study with a primary goal aimed at understanding the sulfur cycle in a remote marine atmosphere. The study will be conducted in August and September months of 2007 at Christmas Island on board the NSF/NCAR C-130 aircraft. It will foremost focu... Show moreThe Pacific Atmospheric Sulfur Experiment (PASE) is a study with a primary goal aimed at understanding the sulfur cycle in a remote marine atmosphere. The study will be conducted in August and September months of 2007 at Christmas Island on board the NSF/NCAR C-130 aircraft. It will foremost focus on measurements of DMS (dimethyl sulfide) and its contribution to formation of H₂SO₄ (sulfuric acid) and MSA (methane-sulfonic acid) by reaction with OH (hydroxyl). PASE will also concentrate on subsequent production of aerosols and cloud condensation nuclei from H₂SO₄, MSA, and NH₃ concentrations in a cloud free convective boundary layer (CBL) and in outflow of marine cumulus. This paper explains the measurement technique for OH, H₂SO₄, MSA, HO₂, HO₂+RO₂ (peroxy radicals), and NH₃ (ammonia) using the SICIMS (Selected ion chemical ionization mass spectrometer). It also presents sample measurements from test flights of OH, H₂SO4, MSA, HO₂, and HO₂+RO₂. In addition, this paper discusses the measurement technique utilized aboard the C-130 in testing SO₂, DMS, DMSO (dimethyl sulfoxide), DMSO₂ (dimethyl sulfone), O₃ (ozone), aerosols, and cloud condensation nuclei. It includes several adaptations to technique and instrumentation from previous studies conducted: the First Aerosol Characterization Experiment (ACE-1) in 1998, the Pacific Exploratory Missions A and B (PEM-Tropics) in 1996, and the Intercontinental Transport Experiment (INTEX-B) in 2006. Show less
