Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 7 2 2007 10.5194/acpd-7-5675-2007 http://www.atmos-chem-phys-discuss.net/7/5675/2007/ http://www.atmos-chem-phys-discuss.net/7/5675/2007/acpd-7-5675-2007.html http://www.atmos-chem-phys-discuss.net/7/5675/2007/acpd-7-5675-2007.pdf 5675 5700 2007-04-27 A GCM study of organic matter in marine aerosol and its potential contribution to cloud drop activation G. J. Roelofs roelofs@phys.uu.nl Institute for Marine and Atmospheric Research Utrecht (IMAU), Utrecht University, Utrecht, The Netherlands With the global aerosol-climate model ECHAM5-HAM we investigate the potential influence of organic aerosol originating from the ocean on aerosol mass and chemical composition and the droplet concentration and size of marine clouds. We present sensitivity simulations in which the uptake of organic matter in the marine aerosol is prescribed for each aerosol mode with varying organic mass and mixing state, and with a geographical distribution and seasonality similar to the oceanic emission of dimethyl sulfide. Measurements of aerosol mass and chemical composition serve to evaluate the representativity of the model initializations. Good agreement with the measurements is obtained when organic matter is added to the Aitken, accumulation and coarse modes simultaneously. Representing marine organics in the model leads to higher cloud drop number concentrations, smaller cloud drop effective radii, and a better agreement with remote sensing measurements. The mixing state of the organics and the other aerosol matter, i.e., internal or external depending on the formation process of aerosol organics, is an important factor for this. We estimate that globally about 75 Tg C yr^−1 of organic matter from marine origin enters the aerosol phase. An approximate 35% of this occurs through formation of secondary organic aerosol and 65% through emission of primary particles. Andreae, M. O., Jones, C. D., and Cox, P. M.: Strong present-day cooling implies a hot future, Nature, 435, 1187–1190, doi:10.1038/nature03671, 2005. Bennartz, R.: Global assessment of marine boundary layer cloud droplet umber concentration from satellite, J. Geophys. Res., 112, D02201, doi:10.1029/2006JD007547, 2007. Berg, W. W. and Winchester, J. W.: Aerosol chemistry of the marine atmosphere, in: Chemical Oceanography, edited by: Riley, J. P. and Chester, R., 7, pp. 173–231, Academic Press, London, 1978. Boers, R., Acaterra, J. R. and Gras, J. L.: Satellite monitoring of the first indirect effect: Retrieval of the droplet concentration of water clouds, J. Geophys. Res., 111, D22208, doi:10.1029/2005JD006838, 2006. Claeys, M., Graham, B., Vas, G., Wang, W., Vermeylen, R., Pashynska, V., Cafmeyer, J., Guyon, P., Andreae, M. O., Aetaxo, P., and Maenhout, W.: Formation of secondary organic aerosols through photooxidation of isoprene, Science, 303, 1173–1176, doi:10.1126/science.1092805, 2004. Fizgerald, J. W.: Marine aerosols: a review, Atmos. Environ. A, 25, 533–545, 1991. Girshick, S. L. and Chiu, C.-P.: Kinetic nucleation theory: A new expression for the rate of homogeneous nucleation from an ideal supersaturated vapor, J. Chem. Phys., 93, 1273–1277, 1990. Goldstein, A. H. and Galbally, I. E.: Known and unexplored organic constituents in the Earth's atmosphere, Environ. Sci. Technol., 1515–1521, 2007. Han, Q., Rossow, W. B., and Lacis, A. A.: Near-global survey of effective droplet radii in liquid water clouds using ISCCP data, J. Climate, 7, 465–497, 1994. Hänel, G.: The role of aerosol properties during the condensational stage of cloud: a reinvestigation of numerics and microphysics, Beitr. Phys. Atmos., 60, 321–339, 1987. Heintzenberg, J., Covert, D. C. and van Dingenen, R.: Size distribution and chemical composition of marine aerosols: a review, Tellus 52B, 1104–1122, 2000. Hoffman, E. J. and Duce, R. A.: Factors influencing the organic carbon content of atmospheric sea salt particles: A laboratory study, J. Geophys. Res., 81, 3667–3670, 1976. Jacobson, M. C., Hansson, H. C., Noone, K. J. and Charlson, R. J.: Organic atmospheric aerosols: Review and state of the science, Rev. Geophys., 38, 267–294, 2000. Kanakidou, M., Seinfeld, J. J., Pandis, S. N., et al.: Organic aerosol and global climate modeling: a review, Atmos. Chem. Phys., 5, 1053–1123, 2005. Kerminen, V. M.: Relative roles of secondary sulfate and organics in atmospheric cloud condensation nuclei production, J. Geophys. Res., 106, 17 321–17 333, 2001. Kulmala, M., Pirjola, L. and Mäkelä, J.: Stable sulphate clusters as a source of new atmospheric particles, Nature, 404, 66–69, 2000. Lohmann, U. and Roeckner, E.: Design and performance of a new cloud microphysics scheme developed for the ECHAM4 general circulation model, Clim. Dyn., 12, 557–572, 1996. Lohmann, U. and Lesins, G.: Stronger constraints on the anthropogenic indirect aerosol effect, Science, 298, doi:10.1126/science.1075405, 2002. Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715–737, 2005. Meshkidze, N. and Nenes, A.: Phytoplankton and cloudiness in the southern ocean, Science, 314, 1419–1423, doi:10.1126/science.1131779, 2006. O'Dowd, C. D., Smith, M. H., Consterdine, I. E. and Lowe, J. A.: Marine aerosol, sea-salt, and the marine sulphur cycle: a short review, Atmos. Environ., 31, 73–80, 1997. O'Dowd, C. D., Facchini, M. C., Cavalli, F., Ceburnis, D., Mircea, M., Decesari, S., Fuzzi, S., Yoon, Y. J., and Putaud, J.-P.: Biogenically-driven organic contribution to marine aerosol, Nature, 431, 676–680, 2004. Penner, J. E., Andreas, M., Annegarn, H., et al.: Aerosols, their direct and indirect effects, in: Climate Change 2001: The Scientific Basis, edited by: Houghton, J. T., Ding, D. J., Griggs, M., et al., 289–348, Cambridge University Press, Cambridge, 2001. Roelofs, G. J., Ganzeveld, L. G., and Lelieveld, J.: Simulation of global sulfate distribution and the influence on effective cloud drop radii with a coupled photochemistry-sulfur~cycle model, Tellus 50B, 224–242, 1998. Roelofs, G. J., Stier, P., Feichter, J., Vignati, E., and Wilson, J.: Aerosol activation and cloud processing in the global aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 6, 2389–2399, 2006. Stier, P., Feichter, J., Kinne, S., Kloster, S., Vignati, E., Wilson, J., Ganzeveld, L., Tegen, I., Werner, M., Balkanski, Y., Schulz, M., and Boucher, O.: The aerosol-climate model ECHAM5-HAM, Atmos. Chem. Phys., 1125–1156, 2005. Textor, C., Schulz, M., Guibert, S., et al.: Analysis and quantification of the diversities of aerosol life cycles within AeroCom, Atmos. Chem. Phys., 6, 1777–1813, 2006. Vignati, E., Wilson, J. and Stier, P.: M7: An efficient size-resolved aerosol microphysics module for large-scale aerosol transport models, J. Geophys. Res., 109, D22202, doi:10.1029/2003JD004485, 2004. Wilson, J., Cuvelier, C., and Raes, F.: A modeling study of global mixed aerosol fields, J. Geophys. Res., 106, 34 081–34 108, 2001. Yokouchi, Y., Li, H. J., Machida, T., Aoki, S., and Akimoto, H.: Isoprene in the marine boundary layer (Southeast Asian Sea, eastern Indian Ocean, and Southern Ocean): comparison with dimethyl sulfide and bromoform, J. Geophys. Res., 104, 8067–8076, 1999.