EarthRef.org Reference Database (ERR)
Development and Maintenance by the EarthRef.org Database Team

Detailed Reference Information
Carslaw et al. 1999
Carslaw, N., Jacobs, P.J. and Pilling, M.J. (1999). Modeling OH, HO2, and RO2 radicals in the marine boundary layer: 2. Mechanism reduction and uncertainty analysis. Journal of Geophysical Research 104: doi: 10.1029/1999JD900782. issn: 0148-0227.

An observationally constrained box model has been constructed to investigate radical chemistry at the Mace Head Atmospheric Observatory, a remote marine location on the west coast of Ireland. The primary aim of the model has been to model concentrations of the hydroxyl (OH), hydroperoxy (HO2), and the sum of peroxy &Sgr;(2>+2>) radicals measured by in situ instruments at this location. The model used in these studies consists of about 1670 reactions and 500 species, and model predictions of radical concentrations have been evaluated against field data. In order to further understand the chemistry, the model has been reduced using sensitivity analysis on both a clean and a semipolluted day. For reduced mechanisms that predict the concentrations of OH and HO2 to within 5% of the full mechanism, the semipolluted day can be represented using 279 species and 986 reactions, and the clean day using 249 species and 894 reactions. A further reduction has been applied whereby the reduced mechanisms predict concentrations of OH and HO2 to within 20% of the full mechanism for the daytime hours. In this way, the OH and HO2 concentrations on the semipolluted day can be represented by 42 species and 64 reactions, and the clean day by 17 species and 25 reactions. We show that these reduced mechanisms are generally applicable for this location under broadly similar conditions. Simple steady state expressions have also been derived to represent the chemistry at this location, allowing the concentrations of OH and HO2 to be deduced analytically. The expressions are based on the reduced mechanisms and on a further analysis of the reaction rates. Finally, an uncertainty analysis has been carried out to quantify the effects of propagation of uncertainties in the rate parameters and constrained concentrations through to the calculated radical concentrations in the model. For model concentrations of OH, HO2, and &Sgr;(2>+2>) radicals, the 2&sgr; uncertainties are 31, 21, and 25%, respectively for clean air, and 42, 25, and 27% for semipolluted air. ¿ 1999 American Geophysical Union

BACKGROUND DATA FILES

Abstract

Keywords
Atmospheric Composition and Structure, Constituent sources and sinks, Atmospheric Composition and Structure, Troposphere—composition and chemistry, Mathematical Geophysics, Modeling, Meteorology and Atmospheric Dynamics, Numerical modeling and data assimilation
Journal
Journal of Geophysical Research
http://www.agu.org/journals/jb/
Publisher
American Geophysical Union
2000 Florida Avenue N.W.
Washington, D.C. 20009-1277
USA
1-202-462-6900
1-202-328-0566
service@agu.org
Click to clear formClick to return to previous pageClick to submit