ACP Atmospheric Chemistry and Physics ACP 1680-7324 Copernicus GmbH Göttingen, Germany 10.5194/acp-10-5749-2010 Size-dependent aerosol deposition velocities during BEARPEX'07 Vong R. J. 1 Vong I. J. 1 Vickers D. 1 Covert D. S. 2 College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, OR 97331, USA Joint Institute for the Study of Atmospheres and Oceans, University of Washington, Seattle, WA 98195, USA 30 06 2010 10 12 5749 5758 This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. This article is available from http://www.atmos-chem-phys.net/10/5749/2010/acp-10-5749-2010.html The full text article is available as a PDF file from http://www.atmos-chem-phys.net/10/5749/2010/acp-10-5749-2010.pdf

Aerosol concentrations and 3-D winds were measured from 9 to 25 September 2007, above a pine forest in California. The measurements were combined using the eddy covariance (EC) technique to determine aerosol eddy fluxes as a function of particle diameter within the accumulation mode size range (0.25 μm&le;<i>D</i><sub>p</sub>&le;1 μm here). Measured heat and water vapor fluxes were utilized to correct the aerosol eddy fluxes for aerosol hygroscopic growth. The hygroscopic growth correction was necessary despite the low RH and relatively hygrophobic nature of the particles. Uncertainties associated with particle counting also were evaluated from the data. Aerosol deposition velocities (<i>V</i><sub>d</sub> = EC turbulent flux/mean particle concentration) during daytime were shown to vary from −0.2 to −1.0 cm s<sup>−1</sup>; the magnitude of particle <i>V</i><sub>d</sub> increases with friction velocity and particle diameter.

 References Baron, P. and Willeke, K.: Aerosol Measurement: Principles, Techniques, and Applications, Wiley-InterScience, 2005. Carrico, C. M., Kreidenweis, S. M., Malm, W. C., Day, D. E. Lee, T., Carrillo, J., McMeeking, G. R., and Collett, J. L.: Hygroscopic growth behavior of a carbon-dominated aerosol in Yosemite National Park, Atmos. Environ. 39, 1393–1404, 2005. Charlson, R. J., Schwartz, S. E., Hales, J. M., Cess, R. D., Coakley, J. A., Hansen, J. E., and Hofmann, D. J.: Climate forcing by anthropogeic aerosols, Science, 255, 423–430, 1992. Charlson, R. J., Lovelock, J. E., Andreae, M. O., and Warren, S. G.: Oceanic phytoplanton, atmospheric sulfur, cloud albedo, and climate, Nature, 326, 655–661, 1987. Erisman, J. W., Draaijers, G., Duyzer, J., Hofschreuder, P., VanLeeuwen, N., et al.: Particle deposition to forests-summary of results and application, Atmos. Environ. 31, 321–332, 1997. Eugster, W. and Senn, W.: A cospectral correction for measurement of turbulent NO<sub>2</sub> flux, Bound.-Lay. Meteorol., 74, 321–340, 1995. Fairall, C. W.: Interpretation of eddy correlation measurements of particulate dry deposition, Atmos. Environ., 18, 3129–3137, 1984. Foken, T., Gockede, M., Mauder, M., Mahrt, L., Amiro, B., and Munger, W.: Post-field data quality control, in: Handbook of Micrometeorology edited by: Lee, X., Massman, W., and Law, B., Kluwer Academic Press, Dordrecht, The Netherlands, 181–208, 2004. Gallagher, M. W., Beswick, K. M., Duyzer, J., Westrate, H., Choularton, T. W., and Hullmmelshoj, P.: Measurements of aerosol fluxes to Speulder Forest using a micrometeorological technique, Atmos. Environ. 31, 359–373, 1997. Goldstein, A. H., Hultman, N. E., Fracheboud, J. M., Bauer, M. R., Panek, J. A., Xu, M., Qi, Y., Guenther, A. B., and Baugh, W.: Effects of climate variability on the carbon dioxide, water, and sensible heat fluxes above a ponderosa pine plantation in the Sierra Nevada (CA), Agric. Forest Meteorol. 101, 113–129, 2000. Hegg, D. A., Covert, D. S., and Jonsson, H. H.: Measurements of size-resolved hygroscopicity in the California coastal zone, Atmos. Chem. Phys., 8, 7193–7203, doi:10.5194/acp-8-7193-2008, 2008. Hegg, D. A., Covert, D. S., Jonsson, H., and Covert, P. A.: An instrument for measuring size-resolved hygroscopicity at both sub- and super-micron sizes. Aerosol Sci. Technol. 41, 873–883, 2007. Hegg, D. A., Covert, D. S., Crahan, K. K., Jonsson, H. H., and Liu,Y.: Measurements of the Aerosol Size-Resolved Hygroscopicity at Sub and Supermicron Sizes. Geophys. Res. Lett. 33, L21808, doi:10.1029/2006GL026747, 2006. Hicks, B. B., Draxler, R. R., Albritton, D. L., Fehsenfeld, F. C., Dodge, M. C., Schwartz, S. E., Tanner, R. L., Hales, J. M., Meyers, T. P., and Vong, R. J.: Atmospheric Processes Research and Process Model Development, State-of-Science /Technology Report Number 2, National Acidic Precipitation Assessment Program (NAPAP), Washington DC, USA, 1991. Howell, J. F. and Mahrt, L.: Multi-resolution flux decomposition, Bound.-Lay. Meteorol., 83, 117–137, 1997. Junge, C. E.: Air chemistry and radioactivity, International Geophysics Series, Academic Press, New York, USA, 4, 113–123, 1963. Kasten, F.: Visibility forecast in the phase of pre-condensation, Tellus, 21, 631–635, 1969. Kowalski, A. S.: Deliquescence induces eddy covariance and estimable dry deposition errors, Atmos Environ., 35, 4843–4851, 2001. Kowalski, A. S., Anthoni, P. A., Vong, R. J., Delany, A. S., and Maclean, G.: Deployment and evaluation of a system for ground-based measurement of cloud liquid water fluxes, J. Atmos. Ocean. Tech., 14, 468–479, 1997. Lee, X., Finnigan, J., and Paw U, K. T.: Coordinate systems and flux bias error, in: Handbook of Micrometeorology , edited by: Lee, X., Massman, W., and Law, B., Kluwer Academic Press, Dordrecht, The Netherlands, 33–66, 2004. Massling, A., Stock, M., and Wiedensohler, A.: Diurnal, weekly, and seasonal variation of hygroscopic properties of submicrometer urban aerosol particles, Atmos. Environ., 39, 3911–3922, 2005. Moore, C. J.: Frequency response corrections for eddy correlation systems, Boundary Layer Meteorol. 37, 17–35, 1986. Nemitz, E., Gallagher, M. W., Duyzer, J. H., and Fowler, D.: Micrometeorological measurements of particle deposition velocities to moorland vegetation, Q. J. Roy. Meteorol. Soc. 128, 2281–2300, 2002. Pryor, S. Gallagher, M. W., Sievering, H., Larsen, S. E., Barthemie, R. J., Birsan, F., Nemtiz, E., Rinne, J., Kulmala, M., Gronholm, T., Taipale, R., and Vesala, T.: A review of measurement and modeling results of particle atmosphere-surface exchange, Tellus 60B, 42-75, 2008. Seinfeld, J. H. and Pandis, S. N.: Atmospheric chemistry and physics: from air pollution to climate change, Wiley and Sons, New York, USA, 969–971, 1998. Slinn, W. G. N.: Predictions for particle deposition to vegetative canopies, Atmos. Environ., 16, 1785–1794, 1982. Vickers, D. and Mahrt, L.: Quality control and flux sampling problems for tower and aircraft data, J. Atmos. Ocean. Technol., 14, 512–526, 1997. Vickers, D. and Mahrt, L.: The cospectral gap and turbulent flux calculations, J. Atmos. Ocean. Technol., 20, 660–672, 2003. Vong, R. J., Vickers, D., and Covert, D. S.: Eddy correlation measurements of aerosol deposition to grass, Tellus 56B, 105–117, 2004. Webb, E. K., Pearman, G. I., and Leuning, R.: Correction of flux measurements for density effects due to heat and vapor transfer, Q. J. Roy. Meteor. Soc., 106, 85–100, 1980. Wesely, M. L., Cook, D. R., Hart, R. L., and Speer, R. E.: Measurements and parameterization of particulate sulfur dry deposition over grass, J.Geophys. Res., 90, 2131–2143, 1985.