Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 8 1 2008 10.5194/acpd-8-71-2008 http://www.atmos-chem-phys-discuss.net/8/71/2008/ http://www.atmos-chem-phys-discuss.net/8/71/2008/acpd-8-71-2008.html http://www.atmos-chem-phys-discuss.net/8/71/2008/acpd-8-71-2008.pdf 71 94 2008-01-04 Laboratory measurements of the optical properties of sea salt aerosol R. Irshad rirshad@atm.ox.ac.uk R. G. Grainger D. M. Peters R. A. McPheat K. M. Smith G. Thomas Atmospheric, Oceanic and Planetary Physics, Clarendon Laboratory, University of Oxford, UK Space Science and Technology Department, Rutherford Appleton Laboratory, Didcot, UK The extinction spectra of laboratory generated sea salt aerosols have been measured from 1 μm to 20 μm using a Bruker 66v/S FTIR spectrometer. Concomitant measurements include temperature, pressure, relative humidity and the aerosol size distribution. The refractive indices of the sea salt have been determined using a simple harmonic oscillator band model (Thomas et al., 2004) for aerosol with relative humidities between 0.1% to 100% sea salt. The resulting refractive index spectra show significant discrepancies when compared to existing sea salt refractive indices. Blackford, D B. and Simons, G R.: Particle Size Analysis of Carbon Black, Particle Characterization, 4, 112–117, 1986. Clapp, M L., Miller, R E., and Worsnop, D R.: Frequency-dependent optical-constants of water ice obtained directly from aerosol extinction spectra, J. Phys. Chem., 99, 6317–6326, 1995. Culkin, F.: The major constituents of sea water, in: Chemical Oceanography, edited by: Riley, J P. and Skirrow, G., 1, 121–161, Academic Press, first edn., 1965. Dobbie, J S., Li, J., Harvey, R., and Chylek, P.: Sea-salt optical properties and GCM forcing at solar wavelengths, Atmos. Res., 65, 211–233, 2003. DOE: Handbook of methods for the analysis of the various parameters of the carbon dioxide system in sea water,version 2, oRNL/CDIAC-74, 1994. Dubovik, O., Holben, B., Eck, T F., Smirnov, A., Kaufman, Y J., King, M D., Tanre, D., and Slutsker, I.: Variability of absorption and optical properties of key aerosol types observed in worldwide locations, J. Atmos. Sci., 59, 590–608, 2002. Finlayson-Pitts, B J. and Hemminger, J C.: Physical chemistry of airborne sea salt particles and their components, J. Phys. Chem. A, 104, 11 463–11 477, 2000. Grainger, R G., Lucas, J., Thomas, G E., and Ewen, G. B L.: Calculation of Mie derivatives, Appl. Optics, 43, 5386–5393, 2004. Hale, G M. and Querry, M R.: Optical properties of water in the near infrared, Appl. Optics, 12, 564–568, 1973. Hess, M., Koepke, P., and Schult, I.: Optical Properties of Aerosols and Clouds: The software package OPAC, Bull. Am. Meteorol. Soc., 79, 831–844, 1998. IPCC: The Physical Basis of Climate Change, http://ipcc-wg1.ucar.edu/wg1/wg1-report.html, 2007. Kalman, R E.: A New Approach to Linear Filtering and Prediction Problems, J. Basic Eng., 82, 35, 1960. King, M D., Kaufman, Y J., Tanre, D., and Nakajima, T.: Remote sensing of tropospheric aerosols from space: past, present and future, Bull. Am. Meteorol. Soc., 80, 2229–2259, 1999. Lewis, E R. and Schwartz, S E.: Sea Salt Aerosol Production – Mechanisms, Methods, Measurements, and Models, American Geophysical Union, 2004. Lohmann, U. and Feichter, J.: Global indirect aerosol effects: a review, Atmos. Chem. Phys., 5, 715–737, 2005. Maybeck, P S.: Stochastic Models, Estimation and Control, vol 1, Academic Press Inc., 1979. Milham, M E., Frickel, R H., Embury, J F., and Anderson, D H.: Determination of optical-constants from extinction measurements, J. Opt. Soc. Am., 71, 1099–1106, 1981. Murphy, D M., Anderson, J R., Quinn, P K., McInnes, L M., Brechtel, F J., Kreidenweis, S M., Middlebrook, A M., Posfai, M., Thomson, D S., and Buseck, P R.: Influence of sea-salt on aerosol radiative properties in the Southern Ocean marine boundary layer, Nature, 392, 62–65, 1998. Penner, J E., Andreae, M., Annegarn, H., Barrie, L., Feichter, J F., Hegg, D., Jayaraman, A., Leaitch, R., Murphy, D., Nganga, J., and Pitari, G.: Aerosols, their direct and indirect effects, in: Climate Change 2001: The Scientific Basis. Contribution of Working Group I to the Third Assessment Report of the Intergovernmental Panel on Climate Change, edited by: Houghton, J T., Ding, Y., Griggs, D J., Noguer, M., van~der Linden, P J., Dai, X., Maskell, K., and Johnson, C A., 1, 289–348, Cambridge University Press, first edn., 2001. Rodgers, C D.: Inverse Methods for Atmospheric Sounding: Theory and Practice, vol. Series on Atmospheric, Oceanic and Planetary Physics - Vol. 2, World Scientific Publishing Co. Pte. Ltd., 2000. Rothman, L S.: The HITRAN 2004 molecular spectroscopic database, Journal of Quantitative Spectroscopy and Radiative Transfer, 96, 139–204, 2005. Savoie, D L. and Prospero, J M.: Particle size distribution of nitrate and sulfate in the marine atmosphere, Geophys. Res. Lett., 9, 1207–1210, 1982. Segelstein, D J.: The complex refractive index of water, Master's thesis, University of Missouri – Kansas City, 1981. Shettle, E P. and Fenn, R W.: Models for the Aerosols of the Lower Atmosphere and the Effects of Humidity Variations on Their Optical Properties, AFGL-TR-79-0214, 1979. Thomas, G E., Bass, S F., Grainger, R G., and Lambert, A.: Retrieval of aerosol refractive index from extinction spectra using a damped oscillator band model, Appl. Optics, 44, 1332–1341, 2004. Torres, O., Bhartia, P K., Herman, J R., Ahmad, Z., and Gleason, J.: Derivation of aerosol properties from satellite measurements of backscattered ultraviolet radiation – Theoretical basis, J. Geophys. Res., 103(D14), 17 099–17 110, 1998. Twomey, S. and McMaster, K N.: The production of condensation nuclei by crystallizing salt particles, Tellus, 7, 458–461, 1955. Volz, F E.: Infrared refractive index of atmospheric aerosol substances, Appl. Optics, 11, 755–759, 1972. Wilson, T. R S.: Salinity and the major elements of sea water, in: Chemical Oceanography, edited by: Riley, J P. and Skirrow, G., 1, 365–413, Academic Press, second edn., 1975.