HR: 0830h
AN: A11F-0057    [PDF]
TI: Novel halogen chemistry in the marine boundary layer
AU: * Plane, J M
EM: j.plane@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ United Kingdom
AU: Saiz-Lopez, A
EM: a.saiz-lopez@uea.ac.uk
AF: University of East Anglia, School of Environmental Sciences, Norwich, NR4 7TJ United Kingdom
AU: Shillito, J A
EM: j.shillito@student.umist.ac.uk
AF: UMIST, Department of Physics, P.O. Box 88, Manchester, M60 1QD United Kingdom
AB: This paper will report the first observations of I2 in the marine boundary layer, made by Differential Optical Absorption (DOAS) spectroscopy during a field campaign at Mace Head (Ireland) in the summer of 2002. Very large I2 concentrations correlating with low tide indicate that the source is emission from macro-algae. Simple scaling suggests that this coastal emission could approach 2 Tg per year, making it a major contribution to the global iodine budget. During the same campaign, DOAS observations were also made of the halogen oxides IO, OIO and BrO. The pulses of IO and BrO that were measured at sunrise are strong evidence for heterogeneous processing on sea-salt aerosol producing high levels of IBr during the night. Simple modelling shows that the observed concentrations of the halogen radicals will play important roles in ozone depletion, the oxidation of dimethyl sulfide, and the formation of new particles in the marine boundary layer.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0315 Biosphere/atmosphere interactions
DE: 0330 Geochemical cycles
DE: 0365 Troposphere--composition and chemistry
SC: Atmospheric Sciences [A]
MN: 2003 Fall Meeting