References

ACPD

Atmospheric Chemistry and Physics Discussions

ACPD

1680-7375

Copernicus GmbH

Göttingen, Germany

10.5194/acpd-8-2695-2008

Impact of the new HNO3-forming channel of the HO2+NO reaction on tropospheric HNO3, NOx, HOx and ozone

Cariolle

¹ ² Evans

M. J.

³ Chipperfield

M. P.

³ Butkovskaya

⁴ Kukui

⁵ Le Bras

⁴

Centre Européen de Recherche et Formation Avancée en Calcul Scientifique, Toulouse, France

Météo-France, Toulouse, France

Institute for Atmospheric Science, School of Earth and Environment, University of Leeds, Leeds, UK

Institut de Combustion, Aérothermique, Réactivité et Environnement, CNRS, Orléans, France

Service d'Aéronomie, IPSL, CNRS, Paris, France

11 02 2008

8 1 2695 2713

This is an open-access article ditributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

This article is available from http://www.atmos-chem-phys-discuss.net/8/2695/2008/acpd-8-2695-2008.html

The full text article is available as a PDF file from http://www.atmos-chem-phys-discuss.net/8/2695/2008/acpd-8-2695-2008.pdf

We have studied the impact of the recently established reaction NO+HO2→HNO3 on atmospheric chemistry. A pressure and temperature-dependent parameterisation of this minor channel of the NO+HO2→NO2+OH reaction has been included in both a 2-D stratosphere-troposphere model and a 3-D tropospheric chemical transport model (CTM). Significant effects on the nitrogen species and hydroxyl radical concentrations are found throughout the troposphere, with the largest percentage changes occurring in the tropical upper troposphere (UT). Including the reaction leads to a reduction in NOx everywhere in the troposphere, with the largest decrease of 25% in the tropical and southern hemisphere UT. The tropical UT also has a corresponding large increase in HNO3 of 25%. OH decreases throughout the troposphere with the largest reduction of over 20% in the tropical UT. Mean global decreases in OH are around 13% which leads to a increase in CH4 lifetime of 5%. Due to the impact of decreased NOx on the OH:HO2 partitioning, modelled HO2 actually increases in the tropical UT on including the new reaction. The impact on tropospheric ozone is a decrease in the range 5 to 12%, with the largest impact in the tropics and southern hemisphere. Comparison with observations shows that in the region of largest changes, i.e. the tropical UT, the inclusion of the new reaction tends to degrade the model agreement. Elsewhere the model comparisons are not able to critically assess the impact of including this reaction. Only small changes are calculated in the minor species distributions in the stratosphere.

References 1

Bey, I., Jacob, D. J., Yantosca, R. M., Logan, J. A., Field, B. D., Fiore, A. M., Li, Q., Liu, H. Y., Mickley, L. J., and Schultz, M. G.: Global modelling of tropospheric chemistry with assimilated meteorology: Model description and evaluation, J. Geophys. Res., 106, 23 073–23 096, 2001.

Butkovskaya, N. I., Kukui, A., Pouvesle, N., and Le Bras, G.: Formation of nitric acid in the gas-phase HO2 + NO reaction: Effects of temperature and water vapor, J. Phys. Chem. A, 109, 6509–6520, 2005.

Butkovskaya, N. I., Kukui, A., and Le Bras, G.: HNO3 forming channel of the HO2 + NO reaction as a function of pressure and temperature in the ranges of 72–600 Torr and 223–323 K, J. Phys. Chem. A, 111, 9047–9053, 2007.

Cantrell, C. A. and Stedman, D. H.: A possible technique for the measurement of atmospheric peroxy radicals, Geophys. Res. Lett., 9, 846–849, 1982.

Cariolle, D. and Brard, B.: The distribution of ozone and active stratospheric species: Result of a two-dimensional atmospheric model, in: Atmospheric Ozone, edited by: Zerefos, C. S. and Ghazi, A., D. Reidel, Higham, Mass., 77–81, 1984.

Cariolle, D. and Teyssèdre, H.: A revised linear ozone photochemistry parameterization for use in transport and general circulation models: Multi-annual simulations, Atmos. Chem. Phys., 7, 2183–2196, 2007.

Emmons, L. K., Hauglustaine, D. A., Muller, J.-F., Carroll, M. A., Brasseur, G. P., Brunner, D., Staehelin, J., Thouret, V., and Marenco, A.: Data composites of airborne observations of tropospheric ozone and its precursors, J. Geophys. Res., 105, 20 497-20 538, 2000.

Evans, M. J. and Jacob, D. J.: Impact of new laboratory studies of N2O$_5$ hydrolysis on global model budgets of tropospheric nitrogen oxides, ozone, and OH, Geophys. Res. Lett., 32, 1–4, 2005.

Krol, M., Leeuwen, P. J., and Lelieveld, J.: Global OH trends inferred from methyl-chloroform measurements, J. Geophys. Res., 103, 10 697–10 711, 1998.

Logan, J. A.: An analysis of ozonesonde data for the troposphere: Recommendations for testing 3-D models and development of a gridded climatology for tropospheric ozone, J. Geophys. Res., 104, 16 115–16 149, 1999.

Prinn, R. G., Huang, J., Weiss, R. F., et al.: Evidence for substantial variations in atmospheric hydroxyl radicals in the past two decades, Science, 292, 1882–1888, 2001.

Sander, S. P. , Friedl, R. R., Golden, D. M., Kurylo, M. J., Moortgat, G. K., Keller-Rudek, H., Wine, P. H., Ravishankara, A. R., Kolb, C. E., Molina, M. J., Finlayson-Pitts, B. J., Huie, R. E., and Orkin, V. L.: Chemical Kinetics and Photochemical Data for Use in Atmospheric Studies, JPL Publication 06-2, Evaluation no. 15, 2006.

Spivakovsky, C. M., Logan, J. A., Montzka, S. A., et al.: Three-dimensional climatological distribution of tropospheric OH: Update and evaluation, J. Geophys. Res., 105(D7), 8931–8980, 2000.

Stevenson, D. S., Dentener, F. J., Schultz, M. G., et al.: Multimodel ensemble simulations of present-day and near future tropospheric ozone, J. Geophys. Res., 111, D08301, doi:10.1029/2005JD006338, 2006.

Wayne, R.: Chemistry of Atmospheres, Oxford University Press, 2000.