Atmos. Chem. Phys. Discuss., 11, 10973-11006, 2011
© Author(s) 2011. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Investigating organic aerosol loading in the remote marine environment
K. Lapina1, C. L. Heald1, D. V. Spracklen2, S. R. Arnold2, J. D. Allan3, H. Coe3, G. McFiggans3, S. R. Zorn4,*, F. Drewnick4, T. S. Bates5, L. N. Hawkins6, L. M. Russell6, A. Smirnov7, C. D. O'Dowd8, and A. J. Hind9
1Dept. of Atmospheric Science, Colorado State University, Fort Collins, CO, USA
2University of Leeds, Leeds, UK
3The University of Manchester, Manchester, UK
4Max Planck Institute for Chemistry, Mainz, Germany
5Pacific Marine Environmental Laboratory, NOAA, Seattle, WA, USA
6Scripps Institution of Oceanography, University of California at San Diego, La Jolla, CA, USA
7NASA/Goddard Space Flight Center, Greenbelt, MD, USA
8School of Physics and Centre for Climate and Air Pollution Studies, National University of Ireland Galway, Galway, Ireland
9Bigelow Laboratory for Ocean Sciences, West Boothbay Harbor, ME, USA
*now at: Harvard University, Cambridge, MA, USA

Abstract. Aerosol loading in the marine environment is investigated using aerosol composition measurements from several research ship campaigns (ICEALOT, MAP, RHaMBLe, VOCALS and OOMPH), observations of total AOD column from satellite (MODIS) and ship-based instruments (Maritime Aerosol Network, MAN), and a global chemical transport model (GEOS-Chem). This work represents the most comprehensive evaluation of oceanic OM emission inventories to date, by employing aerosol composition measurements obtained from campaigns with wide spatial and temporal coverage. The model underestimates AOD over the remote oceanic regions on average by 13–30%, compared to satellite and MAN observations. Comparison with cruise data demonstrates that the GEOS-Chem simulation of marine sulfate, with the mean observed values ranging between 0.22 μg m−3 and 1.34 μg m−3, is generally unbiased, however surface organic matter (OM) concentrations, with the mean observed concentrations between 0.07 μg m−3 and 0.77 μg m−3, are largely underestimated. We find that ship-based measurements are consistent with a sub-micron marine OM source of 9 TgC yr−1 or less, however this additional OM source does not explain the model underestimate of marine AOD.

Citation: Lapina, K., Heald, C. L., Spracklen, D. V., Arnold, S. R., Allan, J. D., Coe, H., McFiggans, G., Zorn, S. R., Drewnick, F., Bates, T. S., Hawkins, L. N., Russell, L. M., Smirnov, A., O'Dowd, C. D., and Hind, A. J.: Investigating organic aerosol loading in the remote marine environment, Atmos. Chem. Phys. Discuss., 11, 10973-11006, doi:10.5194/acpd-11-10973-2011, 2011.
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