Air-side flux measurements UCI API CIMS ( Proton transfer atmospheric pressure ionization)

1. Air-side flux measurements UCI API CIMS (Proton transfer atmospheric pressure ionization) DMS, acetone (10 Hz) Sensitivity ~100 Hz/ppt DMS Currently being downsized (from the “bigCIMS” to the “mesoCIMS”) Requirements: 0.5m3+rack, short tubing run to bow, winds/motion, lab quality power and A/C

2. Continuous seawater measurements for air/sea gradient UCI API CIMS (Proton transfer atmospheric pressure ionization) Low cost, low sensitivity (“miniCIMS”) TFE membrane equilibrator Sensitivity: <0.1nM DMS at 1 minute averaging time, pM acetone Requirements: seawater supply (bow pump, fish), lab space, sink

3. kDMSvs U for low-moderate wind speeds (Marandino et al. 2009)

4. Anomalous DMS gas transfer in N. Atlantic coccolith bloom (Marandino et al. 2009)

6. Air/sea gas transfer coefficients: A multi-study synthesis Christa A. Marandino1*, Warren J. De Bruyn2, Scott D. Miller3, Eric S. Saltzman1 1University of California, Irvine, Irvine, CA, cmarandi@uci.edu 2Chapman University, Orange, CA 3Atmospheric Sciences Research Center, State University of New York, Albany, Albany, NY *now at IFM-GEOMAR, Kiel, Germany Abstract OS31B-1261 • DMS and Dual Tracers: • Comparison of DMS with dual tracer studies: • SAGE (Ho et al., 2006) Georges Bank (Wanninkhof et al., 1993) • GASEX (McGillis et al., 2001b) N. Sea (Nightingale et al., 2000b) • FSLE (Wanninkhof et al., 1997) SOFEX (Wanninkhof et al., 2004) • IRONEX (Nightingale et al., 2000a) • Introduction: • Eddy correlation (EC) flux measurements in 3 ocean basins: • PHASE I - N. and Eq. Pacific, May-July, 2004 • Knorr_06 (K06) - S. Pacific, January, 2006 • Knorr_07 (K07) – N. Atlantic, July, 2007 • DMS air/sea flux (F) and concentrations (ΔC) measured continuously using • atmospheric pressure chemical ionization mass spectrometer (API-CIMS) • and Campbell C-SAT 3 sonic anemometer • DMS seawater levels continuously measured at 5 m depth using a • membrane equilibrator • Gas transfer coefficient (k) computed using k=F/ ΔC • The wind speed dependence of k examined and compared to that of other • DMS studies, as well as CO2 and dual tracer studies • DMS Studies • Comparison of 5 published DMS EC studies: • PHASE I • K06 • K07 • H04 (Huebert et al., 2004) • BIO (Blomquist et al., 2006) • Similar results across all • cruises • Similar k vs U for • DMS and dual tracers • Implications - • 1) over this U range, DMS transfer due to same physics as inert gases, • 2) no evidence of interfacial DMS chemical/biological production/loss. EC sampling setup for K07 DMS and CO2 on ship mast • Linear regression, 95% • confidence intervals: • k = 0.55U – 0.55 • r2 = 0.78 • DMS and CO2 • compare to CO2 direct flux studies • with derived k values: • GASEX-98 (McGillis et al., 2001a) • GASEX-01 (McGillis et al., 2004) • Knorr_07 (K07, Miller et al., subm.) • DMS more linear than GASEX-98 • Steeper k vs U than GASEX-01 • at low wind speed despite similar • oceanographic conditions • Big Questions Remain • What factors control the wind speed dependence of k? • Is k vs. U relationship the same for all trace gases? • Can k values always be determined from 5 m depth Cw values? • What about high winds • Do blooms alter k for some or all trace gases? k values derived from N. Atlantic EC measurements: • pink points inside summer coccolith bloom, black points outside bloom • k values inside bloom up to 5x higher than outside Implications – • evidence of near surface DMS gradients? • N. Atlantic DMS fluxes greater than previous estimates? • DMS contribution to sulfate aerosol loading larger than predicted? • 2nd order polynomial • regression, 95% confidence • intervals: • k = 0.04U2+0.05U+0.68 • r2 = 0.81 • DMS more similar to K07 CO2 • K07 CO2 measured concurrently w/ K07 DMS • All exhibit less dependence on U • than GASEX-98 and more than • GASEX-01 Acknowledgements: Thanks to Oregon St. & WHOI ship op staff and the captain and crew of the R/V Knorr, Cyril McCormick, the Saltzman lab past and present. Funding provided by the NSF Atmospheric Chemistry Program. This is a contribution to the U.S. Solas Project. References: Blomquist, B., et al. (2006), Geophys. Res. Lett., 33, doi: 10.1029/206GL025735. Fairall, C., et al. (1996), J. Geophys. Res.-Oceans, 101, 3747. Ho, D., et al. (2006), Geophys. Res. Lett., 33, doi: 10.1029/2006GL026817. Huebert, B., et al. (2004), Geophys. Res. Lett., 31, doi:10.1029/2004GL021567. McGillis, W., et al. (2004), J. Geophys. Res.-Oceans, 109, doi:10.1029/2003JG002256. McGillis, W., et al. (2001a), J. Geophys. Res.-Oceans, 106, 16729. McGillis, W., et al. (2001b), Mar. Chem., 75, 267. Miller, S., et al. (in press), Geophys. Res. Lett.. Nightingale, P., et al. (2000a), Geophys. Res. Lett., 27, 2117. Nightingale, P., et al. (200b), Global Biogeochem. Cycles, 14, 373. Wanninkhof, R., et al. (2004), J. Geophys. Res.-Oceans, 109, doi:10.1029/2003JC001767 Wanninkhof, R., et al. (1997), Geophys. Res. Lett. 24, 1767. Wanninkhof, R., et al. (1993), J. Geophys. Res.-Oceans, 98, 20237. Wanninkhof, R. (1992), J. Geophys. Res., 97, 7373.