Radiative forcing in the 21st century due to ozone changes in the troposphere and the lower stratosphere

Gauss, M and Myhre, G and Pitari, G and Prather, M J and Isaksen, I S A and Berntsen, T K and Brasseur, G P and Dentener, F J and Derwent, R G and Hauglustaine, D A and Horowitz, L W and Jacob, D J and Johnson, M and Law, K S and Mickley, L J and Muller, J F and Plantevin, P H and Pyle, J A and Rogers, H L and Stevenson, D S and Sundet, J K and van Weele, M and Wild, O (2003) Radiative forcing in the 21st century due to ozone changes in the troposphere and the lower stratosphere. Journal of Geophysical Research: Atmospheres, 108 (D9): 4292. -. ISSN 0747-7309

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Radiative forcing due to changes in ozone is expected for the 21st century. An assessment on changes in the tropospheric oxidative state through a model intercomparison ("OxComp'') was conducted for the IPCC Third Assessment Report (IPCC-TAR). OxComp estimated tropospheric changes in ozone and other oxidants during the 21st century based on the "SRES'' A2p emission scenario. In this study we analyze the results of 11 chemical transport models (CTMs) that participated in OxComp and use them as input for detailed radiative forcing calculations. We also address future ozone recovery in the lower stratosphere and its impact on radiative forcing by applying two models that calculate both tropospheric and stratospheric changes. The results of OxComp suggest an increase in global-mean tropospheric ozone between 11.4 and 20.5 DU for the 21st century, representing the model uncertainty range for the A2p scenario. As the A2p scenario constitutes the worst case proposed in IPCC-TAR we consider these results as an upper estimate. The radiative transfer model yields a positive radiative forcing ranging from 0.40 to 0.78 W m(-2) on a global and annual average. The lower stratosphere contributes an additional 7.5-9.3 DU to the calculated increase in the ozone column, increasing radiative forcing by 0.15-0.17 W m(-2). The modeled radiative forcing depends on the height distribution and geographical pattern of predicted ozone changes and shows a distinct seasonal variation. Despite the large variations between the 11 participating models, the calculated range for normalized radiative forcing is within 25%, indicating the ability to scale radiative forcing to global-mean ozone column change.

Item Type:
Journal Article
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Journal of Geophysical Research: Atmospheres
?? chemical-transport modelgeneral-circulation modelsemi-lagrangian transportaircraft mozaic datatracer transportatmospheric transport3-dimensional modelphotochemical modelglobal tropospherenitrogen-oxides ??
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07 Sep 2011 13:15
Last Modified:
31 Dec 2023 00:22