HR: 1340h
AN: A43A-0886    [Abstracts]
TI: North Atlantic Measurements of DMS Air/Sea Gradient and Eddy Covariance Flux Using API- CIMS
AU: * Marandino, C A
EM: cmarandi@uci.edu
AF: University of California, Irvine, Earth System Science 1212 Croul Hall, Irvine, CA 92697, United States
AU: De Bruyn, W J
EM: debruyn@chapman.edu
AF: Chapman University, Department of Chemistry 1 University Dr., Orange, CA 92866, United States
AU: Miller, S D
EM: smiller@albany.edu
AF: Atmospheric Sciences Research Center, 251 Fuller Rd., Albany, NY 12203,
AU: Saltzman, E S
EM: esaltzma@uci.edu
AF: University of California, Irvine, Earth System Science 1212 Croul Hall, Irvine, CA 92697, United States
AB: Dimethylsulfide (DMS) air/sea concentrations and eddy covariance fluxes were measured aboard the R/V Knorr in the North Atlantic Ocean in July 2007. The cruise track extended from Iceland to Woods Hole, MA. Winds were largely westerly over the cruise track and varied from 1-16 m s^-1. The meteorological conditions were cold and cloudy, with some periods of fog and rain. Atmospheric DMS levels were measured by atmospheric pressure chemical ionization mass spectrometry (API-CIMS). Seawater DMS levels were measured by API-CIMS using a membrane equilibrator fed by the ship's bow pumping system. DMS levels ranged from 2-40 nM in seawater and 85-5500 ppt in air, with the highest levels northward of the subpolar front, in the North Atlantic spring bloom. DMS flux exhibited the same trend, with fluxes ranging from 1-324 μmol m^-2 d^{- 1}. Gas transfer coefficients (k) for DMS were computed from the data. Preliminary analysis indicates that k obtained during this study shows a stronger dependence on wind speed than those from previous measurements based on DMS fluxes (Marandino et al., 2007; Huebert et al., 2004). This dependence is more similar to those from GASEX (McGillis et al., 2001) than and those predicted by Wanninkhof (1992).
DE: 0365 Troposphere: composition and chemistry
DE: 3307 Boundary layer processes
DE: 3394 Instruments and techniques
DE: 4504 Air/sea interactions (0312, 3339)
DE: 4803 Analytical chemistry
SC: Atmospheric Sciences [A]
MN: 2007 Fall Meeting