• Antyufeev, V. S., 1996: Solution of the generalized transport equation with a peak-shaped indicatrix by the Monte Carlo method. Russ. J. Numer. Anal. Math. Model., 11 , 113137.

    • Search Google Scholar
    • Export Citation
  • Barker, H. W., J-J. Morcrette, and G. D. Alexander, 1998: Broadband solar fluxes and heating rates for atmospheres with 3D broken clouds. Quart. J. Roy. Meteor. Soc., 124 , 12451271.

    • Search Google Scholar
    • Export Citation
  • Barker, H. W., R. K. Goldstein, and D. E. Stevens, 2003: Monte Carlo simulation of solar reflectances for cloudy atmospheres. J. Atmos. Sci., 60 , 18811894.

    • Search Google Scholar
    • Export Citation
  • Booth, T. E., 1985: A sample problem for variance reduction in MCNP Los Alamos National Laboratory Rep. LA-10363-MS, 68 pp.

  • Cornet, C., J-C. Buriez, J. Riédi, H. Isaka, and B. Guillemet, 2005: Case study of inhomogeneous cloud parameter retrieval from MODIS data. Geophys. Res. Lett., 32 .L13807, doi:10.1029/2005GL022791.

    • Search Google Scholar
    • Export Citation
  • Evans, K. F., 1998: The spherical harmonics discrete ordinate method for three-dimensional atmospheric radiative transfer. J. Atmos. Sci., 55 , 429446.

    • Search Google Scholar
    • Export Citation
  • Evans, K. F., and A. Marshak, 2005: Numerical methods. 3D Radiative Transfer for Cloudy Atmospheres, A. B. Davis and A. Marshak, Eds., Springer-Verlag, 243–281.

    • Search Google Scholar
    • Export Citation
  • Fu, Q., M. C. Caribb, H. W. Barker, S. K. Krueger, and A. Grossman, 2000: Cloud geometry effects on atmospheric solar absorption. J. Atmos. Sci., 57 , 11561168.

    • Search Google Scholar
    • Export Citation
  • Hönninger, G., C. von Friedeburg, and U. Platt, 2004: Multi axis differential optical absorption spectroscopy (MAX-DOAS). Atmos. Chem. Phys., 4 , 231254.

    • Search Google Scholar
    • Export Citation
  • Iwabuchi, H., and T. Hayasaka, 2003: A multi-spectral non-local method for retrieval of boundary layer cloud properties from optical remote sensing data. Remote Sens. Environ., 88 , 294308.

    • Search Google Scholar
    • Export Citation
  • Kawrakow, I., and D. W. O. Rogers, 2001: The EGSnrc code system: Monte Carlo simulation of electron and photon transport. NRCC Rep. PIRS-701, 287 pp. (revised in 2003).

  • Liou, K-N., 2002: Introduction to Atmospheric Radiation. 2d ed. Academic Press, 583 pp.

  • Macke, A., D. L. Mitchell, and L. V. Bremen, 1999: Monte Carlo radiative transfer calculations for inhomogeneous mixed phase clouds. Phys. Chem. Earth, 24B , 237241.

    • Search Google Scholar
    • Export Citation
  • Marchuk, G., G. Mikhailov, M. Nazaraliev, R. Darbinjan, B. Kargin, and B. Elepov, 1980: The Monte Carlo Methods in Atmospheric Optics. Springer-Verlag, 208 pp.

    • Search Google Scholar
    • Export Citation
  • Martin, G. M., D. W. Johnson, and A. Spice, 1994: The measurement and parameterization of effective radius of droplets in warm stratocumulus clouds. J. Atmos. Sci., 51 , 18231842.

    • Search Google Scholar
    • Export Citation
  • Modest, M. F., 2003: Radiative Heat Transfer. 2d ed. Academic Press, 822 pp.

  • Nakajima, T., and M. Tanaka, 1988: Algorithms for radiative intensity calculations in moderately thick atmospheres using a truncation approximation. J. Quant. Spectrosc. Radiat. Transfer, 40 , 5169.

    • Search Google Scholar
    • Export Citation
  • O’Hirok, W., and C. Gautier, 1998: A three-dimensional radiative transfer model to investigate the solar radiation within a cloudy atmosphere. Part I: Spatial effects. J. Atmos. Sci., 55 , 21622179.

    • Search Google Scholar
    • Export Citation
  • Thomas, G. E., and K. Stamnes, 1999: Radiative Transfer in the Atmosphere and Ocean. Cambridge University Press, 517 pp.

  • Várnai, T., and R. Davies, 1999: Effects of cloud heterogeneities on shortwave radiation: Comparison of cloud-top variability and internal heterogeneity. J. Atmos. Sci., 56 , 42064224.

    • Search Google Scholar
    • Export Citation
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Efficient Monte Carlo Methods for Radiative Transfer Modeling

Hironobu IwabuchiJapan Agency for Marine–Earth Science and Technology, Yokohama, Kanagawa, Japan

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Abstract

Demands for Monte Carlo radiative transfer modeling have grown with the increase in computational power in recent decades. This method provides realistic simulations of radiation processes for various types of application, including radiation budgets in cloudy conditions and remote measurements of clouds, aerosols, and gases. Despite many advantages, such as explicit treatment of three-dimensional radiative transfer, issues of numerical efficiency can make the method intractable, especially in radiance calculations. The commonly used local estimation method requires computationally intensive ray tracing at each collision. Furthermore, the realistic phase function of Mie scattering by cloud and aerosol particles has very sharp peaks in the forward direction. Radiance computations by Monte Carlo methods are inefficient for such spiky phase functions because of significant noise. Moreover, in optically thin regions, sampling of radiance contributions is so rare that long computing times are required to reduce noise. To solve these issues, several variance reduction methods have been proposed. This paper discusses a modified local estimation method, a truncation approximation for a highly anisotropic phase function, a collision-forcing method for optically thin media, a numerical diffusion technique, and several related topics. Numerical experiments demonstrated significant improvements in efficiency for solar radiance calculations in a limited number of cloudy cases.

Corresponding author address: Hironobu Iwabuchi, Frontier Research Center for Global Change, Japan Agency for Marine–Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan. Email: hiro-iwabuchi@jamstec.go.jp

Abstract

Demands for Monte Carlo radiative transfer modeling have grown with the increase in computational power in recent decades. This method provides realistic simulations of radiation processes for various types of application, including radiation budgets in cloudy conditions and remote measurements of clouds, aerosols, and gases. Despite many advantages, such as explicit treatment of three-dimensional radiative transfer, issues of numerical efficiency can make the method intractable, especially in radiance calculations. The commonly used local estimation method requires computationally intensive ray tracing at each collision. Furthermore, the realistic phase function of Mie scattering by cloud and aerosol particles has very sharp peaks in the forward direction. Radiance computations by Monte Carlo methods are inefficient for such spiky phase functions because of significant noise. Moreover, in optically thin regions, sampling of radiance contributions is so rare that long computing times are required to reduce noise. To solve these issues, several variance reduction methods have been proposed. This paper discusses a modified local estimation method, a truncation approximation for a highly anisotropic phase function, a collision-forcing method for optically thin media, a numerical diffusion technique, and several related topics. Numerical experiments demonstrated significant improvements in efficiency for solar radiance calculations in a limited number of cloudy cases.

Corresponding author address: Hironobu Iwabuchi, Frontier Research Center for Global Change, Japan Agency for Marine–Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan. Email: hiro-iwabuchi@jamstec.go.jp

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