Longwave Scattering Effects of Mineral Aerosols

Jean-Louis Dufresne Institute for Computational Earth System Science, University of California at Santa Barbara, Santa Barbara, California

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Catherine Gautier Institute for Computational Earth System Science, University of California at Santa Barbara, Santa Barbara, California

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Paul Ricchiazzi Institute for Computational Earth System Science, University of California at Santa Barbara, Santa Barbara, California

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Yves Fouquart Laboratoire d'Optique Atmosphérique, CNRS-Université de Lille, Villeneuve d'Ascq, France

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Abstract

Scattering in the longwave domain has been neglected in the first generation of radiative codes and is still neglected in most current GCMs. Scattering in the longwave domain does not play any significant role for clear-sky conditions but recent works have shown that it is not negligible for cloudy conditions. This paper highlights the importance of scattering by mineral aerosols in the longwave domain for a wide range of conditions commonly encountered during dust events. The authors show that neglecting scattering may lead to an underestimate of longwave aerosol forcing. This underestimate may reach 50% of the longwave forcing at the top of atmosphere and 15% at the surface for aerosol effective radius greater than a few tenths of a micron. For an aerosol optical thickness of one and for typical atmospheric conditions, the longwave forcing at the top of the atmosphere increases to 8 W m−2 when scattering effects are included. In contrast, the heating rate inside the atmosphere is only slightly affected by aerosol scattering: neglecting it leads to an underestimate by no more than 10% of the cooling caused by aerosols.

Additional affiliation: Laboratoire de Météorologie Dynamique, CNRS-Université Paris 6, Paris, France

Additional affiliation: Geography Department, University of California at Santa Barbara, Santa Barbara, California

Corresponding author address: Dr. Jean-Louis Dufresne, Laboratoire de Météorologie Dynamique (LMD/IPSL), Université Paris 6, boite 99, F-75252 Paris Cedex 05, France. Email: dufresne@lmd.jussieu.fr

Abstract

Scattering in the longwave domain has been neglected in the first generation of radiative codes and is still neglected in most current GCMs. Scattering in the longwave domain does not play any significant role for clear-sky conditions but recent works have shown that it is not negligible for cloudy conditions. This paper highlights the importance of scattering by mineral aerosols in the longwave domain for a wide range of conditions commonly encountered during dust events. The authors show that neglecting scattering may lead to an underestimate of longwave aerosol forcing. This underestimate may reach 50% of the longwave forcing at the top of atmosphere and 15% at the surface for aerosol effective radius greater than a few tenths of a micron. For an aerosol optical thickness of one and for typical atmospheric conditions, the longwave forcing at the top of the atmosphere increases to 8 W m−2 when scattering effects are included. In contrast, the heating rate inside the atmosphere is only slightly affected by aerosol scattering: neglecting it leads to an underestimate by no more than 10% of the cooling caused by aerosols.

Additional affiliation: Laboratoire de Météorologie Dynamique, CNRS-Université Paris 6, Paris, France

Additional affiliation: Geography Department, University of California at Santa Barbara, Santa Barbara, California

Corresponding author address: Dr. Jean-Louis Dufresne, Laboratoire de Météorologie Dynamique (LMD/IPSL), Université Paris 6, boite 99, F-75252 Paris Cedex 05, France. Email: dufresne@lmd.jussieu.fr

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  • Carlson, T., and S. Benjamin, 1980: Radiative heating rates for Saharan dust. J. Atmos. Sci., 37 , 193213.

  • Claquin, T., M. Schulz, Y. Balkanski, and O. Boucher, 1998: Uncertainties in assessing radiative forcing by mineral dust. Tellus, 50B , 491505.

    • Search Google Scholar
    • Export Citation
  • d'Almeida, G., 1987: On the variability of desert aerosol radiative characteristics. J. Geophys. Res., 92 , 30173026.

  • Edwards, J., and A. Slingo, 1996: Studies with a flexible new radiation code. I. Choosing a configuration for a large-scale model. Quart. J. Roy. Meteor. Soc., 122 , 689719.

    • Search Google Scholar
    • Export Citation
  • Forget, F., and Coauthors. 1999: Improved general circulation models of the Martian atmosphere from the surface to above 80 km. J. Geophys. Res., 104 , 2415524175.

    • Search Google Scholar
    • Export Citation
  • Fouquart, Y., B. Bonnel, G. Brogniez, J. Buriez, L. Smith, J. Morcrette, and A. Cerf, 1987: Observations of Saharan aerosols: Results of ECLATS field experiment. Part II: Broadband radiative characteristics of the aerosols and vertical radiative flux divergence. J. Climate Appl. Meteor., 26 , 3852.

    • Search Google Scholar
    • Export Citation
  • Fouquart, Y., J. Buriez, M. Herman, and R. Kandel, 1990: The influence of clouds on radiation: A climate-modeling perspective. Rev. Geophys., 28 , 145166.

    • Search Google Scholar
    • Export Citation
  • Fu, Q., K. Liou, M. Cribb, T. Charlock, and A. Grossman, 1997: Multiple scattering parameterization in thermal infrared radiative transfer. J. Atmos. Sci., 54 , 27992812.

    • Search Google Scholar
    • Export Citation
  • Gomes, L., G. Bergametti, G. Coude-Gaussen, and P. Rognon, 1990: Submicron desert dusts: A sandblasting process. J. Geophys. Res., 95 , 1392713935.

    • Search Google Scholar
    • Export Citation
  • Hansen, J., G. Russell, D. Rind, P. Stone, A. Lacis, S. Lebedeff, R. Ruedy, and L. Travis, 1983: Efficient three-dimensional global models for climate studies: Models I and II. Mon. Wea. Rev., 111 , 609662.

    • Search Google Scholar
    • Export Citation
  • Hansen, J., M. Sato, A. Lacis, R. Ruedy, I. Tegen, and E. Matthews, 1998: Climate forcings in the industrial era. Proc. Nat. Acad. Sci. USA, 95 , 1275312758.

    • Search Google Scholar
    • Export Citation
  • Haywood, J., and O. Boucher, 2000: Estimates of the direct and indirect radiative forcing due to tropospheric aerosols: A review. Rev. Geophys., 38 , 513543.

    • Search Google Scholar
    • Export Citation
  • Lacis, A. A., and M. Mishchenko, 1995: Climate forcing, climate sensitivity, and climate response: A radiative modeling perspective on atmospheric aerosols. Environmental Science Research Rep. ES 17. Aerosol Forcing of Climate, R. Charlson and J. Heintzenberg, Eds., John Wiley and Sons, 11–42.

    • Search Google Scholar
    • Export Citation
  • Liao, H., and J. Seinfeld, 1998: Radiative forcing by mineral dust aerosols: Sensitivity to key variables. J. Geophys. Res., 103 , 3163731645.

    • Search Google Scholar
    • Export Citation
  • Liou, K-N., 1986: Influence of cirrus clouds on weather and climate processes: A global perspective. Mon. Wea. Rev., 114 , 11671199.

  • McClatchey, R. A., R. W. Fenn, J. Selby, and J. Garing, 1972: Optical properties of the atmosphere. Air Force Cambridge Res. Lab. Tech. Rep. AFCRL-72-0497, Bedford, MA, 113 pp.

    • Search Google Scholar
    • Export Citation
  • Miller, R., and I. Tegen, 1998: Climate response to soil dust aerosols. J. Climate, 11 , 32473267.

  • Mishchenko, M. I., A. A. Lacis, B. E. Carlson, and L. D. Travis, 1995: Nonsphericity of dust-like tropospheric aerosols: Implications for aerosol remote sensing and climate modeling. Geophys. Res. Lett., 22 , 10771080.

    • Search Google Scholar
    • Export Citation
  • O'Brien, D., L. Rikus, A. Dilley, and M. Edwards, 1997: Spectral analysis of infrared heating in clouds computed with two-stream radiation codes. J. Quant. Spectrosc. Radiat. Transfer, 57 , 725737.

    • Search Google Scholar
    • Export Citation
  • Pierluissi, J., and G-S. Peng, 1985: New molecular transmission band models for LOWTRAN. Opt. Eng., 24 , 541547.

  • Quijano, A., I. Sokolik, and O. Toon, 2000: Radiative heating rates and direct radiative forcing by mineral dust in cloudy atmospheric conditions. J. Geophys. Res., 105 , 1220712219.

    • Search Google Scholar
    • Export Citation
  • Ricchiazzi, P., S. Yang, C. Gautier, and D. Sowle, 1998: SBDART: A research and teaching software tool for plane-parallel radiative transfer in the Earth's atmosphere. Bull. Amer. Meteor. Soc., 79 , 21012114.

    • Search Google Scholar
    • Export Citation
  • Ritter, B., and J-F. Geleyn, 1992: A comprehensive radiation scheme for numerical weather prediction models with potential applications in climate simulations. Mon. Wea. Rev., 120 , 303325.

    • Search Google Scholar
    • Export Citation
  • Schulz, M., Y. Balkanski, W. Guelle, and F. Dulac, 1998: Role of aerosol size distribution and source location in a three-dimensional simulation of a Saharan dust episode tested against satellite-derived optical thickness. J. Geophys. Res., 103 , 1057910592.

    • Search Google Scholar
    • Export Citation
  • Sokolik, I., and G. Golitsyn, 1993: Investigation of optical and radiative properties of atmospheric dust aerosols. Atmos. Environ., 27 , 25092517.

    • Search Google Scholar
    • Export Citation
  • Sokolik, I., and O. Toon, 1999: Incorporation of mineralogical composition into models of the radiative properties of mineral aerosol from UV to IR wavelengths. J. Geophys. Res., 104 , 94239444.

    • Search Google Scholar
    • Export Citation
  • Sokolik, I., and R. Bergstrom, 1998: Modeling the radiative characteristics of airborne mineral aerosols at infrared wavelengths. J. Geophys. Res., 103 , 88138826.

    • Search Google Scholar
    • Export Citation
  • Stamnes, K., S-C. Tsay, W. Wiscombe, and K. Jayaweera, 1988: Numerically stable algorithm for discrete-ordinate-method radiative transfer in multiple scattering and emitting layered media. Appl. Opt., 27 , 25022509.

    • Search Google Scholar
    • Export Citation
  • Takara, E., and R. Ellingson, 2000: Broken cloud field longwave-scattering effects. J. Atmos. Sci., 57 , 12981310.

  • Tegen, I., and A. Lacis, 1996: Modeling of particle size distribution and its influence on the radiative properties of mineral dust aerosol. J. Geophys. Res., 101 , 1923719244.

    • Search Google Scholar
    • Export Citation
  • Tegen, I., and I. Fung, 1996: The influence on climate forcing of mineral aerosols from disturbed soils. Nature, 380 , 419422.

  • Toon, O., C. Mckay, T. Ackerman, and K. Santhanam, 1989: Rapid calculation of radiative heating rates and photodissociation rates in inhomogeneous multiple scattering atmospheres. J. Geophys. Res., 94 , 1628716301.

    • Search Google Scholar
    • Export Citation
  • Volz, F., 1973: Infrared optical constants of ammonium sulfate, Sahara dust, volcanic pumice, and flyash. Appl. Opt., 12 , 564568.

  • Wiscombe, W., 1980: Improved Mie scattering algorithms. Appl. Opt., 19 , 15051509.

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