Examining Photolysis Rates with a Prototype Online Photolysis Module in CMAQ

Francis S. Binkowski Carolina Environmental Program, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Search for other papers by Francis S. Binkowski in
Current site
Google Scholar
PubMed
Close
,
Saravanan Arunachalam Carolina Environmental Program, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Search for other papers by Saravanan Arunachalam in
Current site
Google Scholar
PubMed
Close
,
Zachariah Adelman Carolina Environmental Program, The University of North Carolina at Chapel Hill, Chapel Hill, North Carolina

Search for other papers by Zachariah Adelman in
Current site
Google Scholar
PubMed
Close
, and
Joseph P. Pinto U.S. Environmental Protection Agency, Research Triangle Park, North Carolina

Search for other papers by Joseph P. Pinto in
Current site
Google Scholar
PubMed
Close
Restricted access

Abstract

A prototype online photolysis module has been developed for the Community Multiscale Air Quality (CMAQ) modeling system. The module calculates actinic fluxes and photolysis rates (j values) at every vertical level in each of seven wavelength intervals from 291 to 850 nm, as well as the total surface irradiance and aerosol optical depth within each interval. The module incorporates updated opacity at each time step, based on changes in local ozone, nitrogen dioxide, and particle concentrations. The module is computationally efficient and requires less than 5% more central processing unit time than using the existing CMAQ “lookup” table method for calculating j values. The main focus of the work presented here is to describe the new online module as well as to highlight the differences between the effective cross sections from the lookup-table method currently being used and the updated effective cross sections from the new online approach. Comparisons of the vertical profiles for the photolysis rates for nitrogen dioxide (NO2) and ozone (O3) from the new online module with those using the effective cross sections from a standard CMAQ simulation show increases in the rates of both NO2 and O3 photolysis.

Corresponding author address: Francis S. Binkowski, UNC-Chapel Hill Carolina Environmental Program, Bank of America Plaza, 137 E. Franklin St., CB 6116, Chapel Hill, NC 27599-6116. Email: frank_binkowski@unc.edu

This article included in the NOAA/EPA Golden Jubilee special collection.

Abstract

A prototype online photolysis module has been developed for the Community Multiscale Air Quality (CMAQ) modeling system. The module calculates actinic fluxes and photolysis rates (j values) at every vertical level in each of seven wavelength intervals from 291 to 850 nm, as well as the total surface irradiance and aerosol optical depth within each interval. The module incorporates updated opacity at each time step, based on changes in local ozone, nitrogen dioxide, and particle concentrations. The module is computationally efficient and requires less than 5% more central processing unit time than using the existing CMAQ “lookup” table method for calculating j values. The main focus of the work presented here is to describe the new online module as well as to highlight the differences between the effective cross sections from the lookup-table method currently being used and the updated effective cross sections from the new online approach. Comparisons of the vertical profiles for the photolysis rates for nitrogen dioxide (NO2) and ozone (O3) from the new online module with those using the effective cross sections from a standard CMAQ simulation show increases in the rates of both NO2 and O3 photolysis.

Corresponding author address: Francis S. Binkowski, UNC-Chapel Hill Carolina Environmental Program, Bank of America Plaza, 137 E. Franklin St., CB 6116, Chapel Hill, NC 27599-6116. Email: frank_binkowski@unc.edu

This article included in the NOAA/EPA Golden Jubilee special collection.

Save
  • Bian, H., and M. J. Prather, 2002: Fast-J2: Accurate simulation of stratospheric photolysis in global chemical models. J. Atmos. Chem., 41 , 281296.

    • Search Google Scholar
    • Export Citation
  • Binkowski, F. S., and U. Shankar, 1995: The Regional Particulate Model: Part I. Model description and preliminary results. J. Geophys. Res., 100 , 2619126209.

    • Search Google Scholar
    • Export Citation
  • Binkowski, F. S., and S. J. Roselle, 2003: Models-3 Community Multiscale Air Quality (CMAQ) model aerosol component. 1. Model description. J. Geophys. Res., 108 .4183, doi:10.1029/2001JD001409.

    • Search Google Scholar
    • Export Citation
  • Byun, D., and J. K. S. Ching, 1999: Science algorithms of the EPA Models-3 Community Multiscale Air Quality (CMAQ) modeling system. U.S. Environmental Protection Agency, Office of Research and Development Science Doc. EPA-600/R-99/030, 776 pp.

  • Dahlback, A., and K. Stamnes, 1991: A new spherical model for computing the radiation field available for photolysis and heating at twilight. Planet. Space Sci., 39 , 671683.

    • Search Google Scholar
    • Export Citation
  • Elterman, L., R. Wexler, and D. T. Chang, 1969: Features of tropospheric and stratospheric dust. Appl. Opt., 8 , 893903.

  • Hess, M., P. Koepke, and I. Schult, 1998: Optical properties of aerosols and clouds: The software package OPAC. Bull. Amer. Meteor. Soc., 79 , 831844.

    • Search Google Scholar
    • Export Citation
  • Horvath, H., 1995: Size segregated light absorption coefficient for the atmospheric aerosol. Atmos. Environ., 29 , 875883.

  • Michalsky, J. J., J. C. Liljegren, and L. C. Harrison, 1995: A comparison of sun photometer derivations of total column water vapor and ozone to standard measures of same at the Southern Great Plains Atmospheric Radiation Measurement site. J. Geophys. Res., 100 , 2599526003.

    • Search Google Scholar
    • Export Citation
  • Sander, S. P., and Coauthors, 2003: Chemical kinetics and photochemical data for use in atmospheric studies, Evaluation Number 14. NASA Jet Propulsion Laboratory Publication 02-25, California Institute of Technology, 334 pp.

  • Stevermer, A., V. Petropavlovskikh, J. M. Rosen, and J. J. DeLuisi, 2000: Development of a global stratospheric climatology: Optical properties and applications for UV. J. Geophys. Res., 105 , 2276322776.

    • Search Google Scholar
    • Export Citation
  • Thomas, G. E., and K. Stamnes, 1999: Radiative Transfer in the Atmosphere and Ocean. Cambridge University Press, 495 pp.

  • Thompson, A. M., and R. W. Stewart, 1991: Effect of chemical kinetics uncertainties on calculated constituents in a tropospheric photochemical model. J. Geophys. Res., 96 , 1308913108.

    • Search Google Scholar
    • Export Citation
  • Toon, O. B., C. P. McKay, and T. P. Ackerman, 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
  • Van Heuklon, T. K., 1979: Estimating atmospheric ozone for solar radiation models. Sol. Energy, 22 , 6368.

  • Wild, O., X. Zhu, and M. J. Prather, 2000: Fast-J: Accurate simulation of in-cloud and below-cloud photolysis in tropospheric chemical models. J. Atmos. Chem., 37 , 245282.

    • Search Google Scholar
    • Export Citation
  • Zeng, J., S. Madronich, and K. Stamnes, 1996: A note on the use of the two-stream delta-scaling approximation for the calculation of atmospheric photolysis rate coefficients. J. Geophys. Res., 101 , 1452514530.

    • Search Google Scholar
    • Export Citation
All Time Past Year Past 30 Days
Abstract Views 0 0 0
Full Text Views 6896 5485 81
PDF Downloads 338 87 11