References

ACP

Atmospheric Chemistry and Physics

ACP

1680-7324

Copernicus GmbH

Göttingen, Germany

10.5194/acp-9-8235-2009

Clouds, photolysis and regional tropospheric ozone budgets

Voulgarakis

¹ ⁴ Wild

² Savage

N. H.

³ Carver

G. D.

¹ Pyle

J. A.

Centre for Atmospheric Science, University of Cambridge, UK

Lancaster Environment Centre, Lancaster University, UK

Met Office, Exeter, UK

now at: the NASA Goddard Inst. for Space Studies & Columbia Univ., Center for Climate Systems Res., New York, USA

03 11 2009

9 21 8235 8246

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.

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The full text article is available as a PDF file from http://www.atmos-chem-phys.net/9/8235/2009/acp-9-8235-2009.pdf

We use a three-dimensional chemical transport model to examine the shortwave radiative effects of clouds on the tropospheric ozone budget. In addition to looking at changes in global concentrations as previous studies have done, we examine changes in ozone chemical production and loss caused by clouds and how these vary in different parts of the troposphere. On a global scale, we find that clouds have a modest effect on ozone chemistry, but on a regional scale their role is much more significant, with the size of the response dependent on the region. The largest averaged changes in chemical budgets (±10–14%) are found in the marine troposphere, where cloud optical depths are high. We demonstrate that cloud effects are small on average in the middle troposphere because this is a transition region between reduction and enhancement in photolysis rates. We show that increases in boundary layer ozone due to clouds are driven by large-scale changes in downward ozone transport from higher in the troposphere rather than by decreases in in-situ ozone chemical loss rates. Increases in upper tropospheric ozone are caused by higher production rates due to backscattering of radiation and consequent increases in photolysis rates, mainly J(NO2). The global radiative effect of clouds on isoprene, through decreases of OH in the lower troposphere, is stronger than on ozone. Tropospheric isoprene lifetime increases by 7% when taking clouds into account. We compare the importance of clouds in contributing to uncertainties in the global ozone budget with the role of other radiatively-important factors. The budget is most sensitive to the overhead ozone column, while surface albedo and clouds have smaller effects. However, uncertainty in representing the spatial distribution of clouds may lead to a large sensitivity of the ozone budget components on regional scales.

References 1

Barth, M C., Hess, P G., and Madronich, S.: Effect of marine boundary layer clouds on tropospheric chemistry as analyzed in a regional chemistry transport model, J. Geophys. Res., 107(D11), 4126, doi:10.1029/2001JD000468, 2002.

Chin, M., Ginoux, P., Kinne, S., Torres, O., Holben, B N., Duncan, B N., Martin, R V., Logan, J A., Higurashi, A., and Nakajima, T.: Tropospheric aerosol optical thickness from the GOCART model and comparisons with satellite and Sun photometer measurements, J. Atmos. Sci., 59, 461–483, 2002.

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, L09813, doi:10.1029/2005GL022469, 2005.

Eyring, V., Butchart, N., Waugh, D W., Akiyoshi, H., Austin, J., Bekki, S., Bodeker, G E., Boville, B A., Brühl, C., Chipperfield, M P., Cordero, E., Dameris, N M., Deushi, M., Fioletov, V E., Frith, S M., Garcia, R R., Gettelman, A., Giorgetta, M A., Grewe, V., Jourdain, L., Kinnison, D E., Mancini, E., Manzini, E., Marchand, M., Marsh, D R., Nagashima, T., Newman, P A., Nielsen, J E., Pawson, S., Pitari, G., Plummer, D A., Rozanov, E., Schraner, M., Shepherd, T G., Shibata, K., Stolarski, R S., Struthers, H., Tian, W., and Ysohiki, M.: Assessment of temperature, trace species, and ozone in chemistry-climate model simulations of the recent past,, J. Geophys. Res., 111, D22 308, doi:10.1029/2006JD007327, 2006.

Hofzumahaus, A., Rohrer, F., Lu, K D., Bohn, B., Brauers, T., Chang, C C., Fuchs, H., Holland, F., Kita, K., Kondo, Y., Li, X., Lou, S R., Shao, M., Zeng, L M., Wahner, A., and Zhang, Y H.: Amplified Trace Gas Removal in the Troposphere, Science, 324, 1702–1704, doi:10.1126/science.1164566, 2009.

IPCC: Climate change 2007: The physical science basis. Contribution of Working Group 1 to the Fourth Assessment Report of the Intergorvernmental Panel on Climate Change, chap. Summary for policymakers, Cambridge University Press, Cambridge, UK, 2007.

Jakob, C.: Cloud cover in the ECMWF reanalysis, J. Climc., 12, 947–959, 1999.

Krol, M C. and VanWeele, M.: Implications of variations in photodissociation rates for global tropospheric chemistry, Atmos. Environ., 31, 1257–1273, 1997.

Laepple, T., Schultz, M G., Lamarque, J.-F., Madronich, S., Shetter, R E., Lefer, B L., and Atlas, E.: Improved albedo formulation for chemistry transport models based on satellite observations and assimilated snow data and its impact on tropospheric chemistry, J. Geophys. Res., 110, D11308, doi:10.1029/2004JD005463, 2005.

Law, K S., Plantevin, P H., Thouret, V., Marenco, A., Asman, W A H., Lawrence, M., Crutzen, P J., Muller, J F., Hauglustaine, D A., and Kanakidou, M.: Comparison between global chemistry transport model results and Measurement of Ozone and Water Vapor by Airbus In-Service Aircraft (MOZAIC) data, J. Geophys. Res., 105, 1503–1525, 2000.

Lefer, B L., Shetter, R E., Hall, S R., Crawford, J H., and Olson, J R.: Impact of clouds and aerosols on photolysis frequencies and photochemistry during TRACE-P: 1. Analysis using radiative transfer and photochemical box models, J. Geophys. Res., 108(D21), 8821, doi:10.1029/2002JD003171, 2003.

Lelieveld, J., Butler, T M., Crowley, J N., Dillon, T J., Fischer, H., Ganzeveld, L., Harder, H., Lawrence, M G., Martinez, M., Taraborrelli, D., and Williams, J.: Atmospheric oxidation capacity sustained by a tropical forest, Nature, 452, 737–740, 2008.

Liu, H., Crawford, J H., Pierce, R B., Norris, P., Platnick, S E., Chen, G., Logan, J A., Yantosca, R M., Evans, M J., Kittaka, C., Feng, Y., and Tie, X.: Radiative effect of clouds on tropospheric chemistry in a global three-dimensional chemical transport model, J. Geophys. Res., 111, D20 303, doi:10.1029/2005JD006403, 2006.

McPeters, R D., Logan, J A., and Labow, G J.: Ozone climatological profiles for Version 8 TOMS and SBUV retrievals, Eos Trans. AGU, 84, p 46, 2003.

Neu, J L., Prather, M J., and Penner, J E.: Global atmospheric chemistry: Integrating over fractional cloud cover, J. Geophys. Res., 112, D11 306, doi:10.1029/2006JD008007, 2007.

Pöschl, U., von Kulhmann, R., Poisson, N., and Crutzen, P J.: Development and intercomparison of condensed isoprene oxidation mechanisms for global atmospheric modelling, J. Atmos. Chem., 37, 29–52, 2000.

Rohrer, F. and Berresheim, H.: Strong correlation between levels of tropospheric hydroxyl radicals and solar ultraviolet radiation, Nature, 442, 184–187, 2006.

Stevenson, D S., Dentener, F J., Schultz, M G., Ellingsen, K., van Noije, T P C., Wild, O., Zeng, G., Amann, M., Atherton, M., Bell, N., Bergmann, D J., Bey, I., Bulter, T., Cofala, J., Collins, W J., Derwent, R G., Doherty, R M., Drevet, J., Eskes, H J., Fiore, A M., Gauss, M., Hauglustaine, D A., Horowitz, L W., Isaksen, I S A., Krol, M C., Lamarque, J.-F., Lawrence, M G., Montanaro, V., Müller, J F., Pitari, G., Prather, M J., Pyle, J A., Rast, S., Rodriguez, J M., Sanderson, M G., Savage, N H., Shindell, D T., Strahan, S E., Sudo, K., and Szopa, S.: Multimodel ensemble simulations of present-day and near-future tropospheric ozone, J. Geophys. Res., 111, D08301, doi:10.1029/2005JD006338, 2006.

Tie, X X., Emmons, L., Horowitz, L., Brasseur, G., Ridley, B., Atlas, E., Stround, C., Hess, P., Klonecki, A., Madronich, S., Talbot, R., and Dibb, J.: Effect of sulfate aerosol on tropospheric NOx and ozone budgets: Model simulations and TOPSE evidence, J. Geophys. Res., 108, 8364, doi:10.1029/2001JD001508, 2003a.

Tie, X X., Madronich, S., Walters, S., Y., Z R., Rasch, P., and Collins, W.: Effect of clouds on photolysis and oxidants in the troposphere, J. Geophys. Res., 108(D20), 4642, doi:10.1029/2003JD003659, 2003b.

Voulgarakis, A., Savage, N. H., Wild, O., Carver, G. D., Clemitshaw, K. C., and Pyle, J. A.: Upgrading photolysis in the $p$-TOMCAT CTM: model evaluation and assessment of the role of clouds, Geosci. Model Dev., 2, 59–72, 2009.

Wild, O.: Modelling the global tropospheric ozone budget: exploring the variability in current models, Atmos. Chem. Phys., 7, 2643–2660, 2007.

Wild, O., Zhu, X., and Prather, M J.: Fast-J: Accurate simulation of in- and below-cloud photolysis in Global Chemical Models, J. Atmos. Chem., 37, 245–282, 2000.

Wu, S., Mickley, L J., Jacob, D J., Logan, J A., Yantosca, R M., and Rind, D.: Why are there large differences between models in global budgets of tropospheric ozone?, J. Geophys. Res., 112, D05 302, doi:10.1029/2006JD007801, 2007.

Young, P. J., Arneth, A., Schurgers, G., Zeng, G., and Pyle, J. A.: The CO2 inhibition of terrestrial isoprene emission significantly affects future ozone projections, Atmos. Chem. Phys., 9, 2793–2803, 2009.