HR: 10:50h
AN: A42B-03    [Abstracts]
TI: Iodine Chemistry at the California Coast
AU: * Pikelnaya, O
EM: olga@atmos.ucla.edu
AF: University of California Los Angeles Department of Atmospheric and Oceanic Sciences, 7127 Mathematical Sciences Building, Los Angeles, CA 90095-1656,
AU: Hurlock, S
EM: steveh@atmos.ucla.edu
AF: University of California Los Angeles Department of Atmospheric and Oceanic Sciences, 7127 Mathematical Sciences Building, Los Angeles, CA 90095-1656,
AU: Stutz, J
EM: jochen@atmos.ucla.edu
AF: University of California Los Angeles Department of Atmospheric and Oceanic Sciences, 7127 Mathematical Sciences Building, Los Angeles, CA 90095-1656,
AB: The chemistry of reactive iodine species (RIS) in clean coastal environments has received considerable attention over the past years. It is known that the presence of reactive iodine in the marine boundary layer (MBL) can catalytically destroy ozone and change the NO/NO₂ and OH/HO₂ ratios. Iodine oxides can also lead to aerosol nucleation in the MBL, potentially affecting the radiative balance of the atmosphere. The limited observational database of RIS, however, restricts our ability to fully understand iodine chemistry, especially in polluted coastal environments, and to assess the significance of reactive iodine on a global scale. Over the past three years, we performed observations of reactive iodine species in the polluted MBL of North America's Atlantic (Isles of Shoals, ME in July-August 2004) and Pacific (Malibu, CA, in March–May 2004 and in October 2006) coasts using concurrent measurements by long-path (LP) and a multi-axis (MAX) differential optical absorption spectroscopy (DOAS) instruments. In this presentation we will focus on the observations of reactive iodine species in Malibu, CA and their behavior with respect to various environmental variables, such as the tidal cycle, wind speed and direction, solar radiation, and NOx levels. The spatial distribution of the reactive iodine species in the coastal MBL is poorly understood, and will be discussed based on the MAX-DOAS measurements and radiative transfer calculations in Malibu and at the Isles of Shoals. A comparison of the RIS observations in Malibu with those at the Isles of Shoals sheds light onto the chemistry of RIS in the polluted coastal environment.
DE: 0312 Air/sea constituent fluxes (3339, 4504)
DE: 0345 Pollution: urban and regional (0305, 0478, 4251)
DE: 0365 Troposphere: composition and chemistry
DE: 0394 Instruments and techniques
DE: 4852 Photochemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting