Journal cover Journal topic
Atmospheric Chemistry and Physics An interactive open-access journal of the European Geosciences Union
Atmos. Chem. Phys., 17, 3279-3299, 2017
http://www.atmos-chem-phys.net/17/3279/2017/
doi:10.5194/acp-17-3279-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
07 Mar 2017
Causes of interannual variability over the southern hemispheric tropospheric ozone maximum
Junhua Liu1,2, Jose M. Rodriguez2, Stephen D. Steenrod1,2, Anne R. Douglass2, Jennifer A. Logan3, Mark A. Olsen2,4, Krzysztof Wargan2,5, and Jerald R. Ziemke2,4 1Universities Space Research Association (USRA), GESTAR, Columbia, MD, USA
2NASA Goddard Space Flight Center, Greenbelt, MD, USA
3School of Engineering and Applied Sciences, Harvard University, Cambridge, MA, USA
4Morgan State University, Baltimore, MD, USA
5Science Systems and Applications, Inc., Lanham, MD, USA
Abstract. We examine the relative contribution of processes controlling the interannual variability (IAV) of tropospheric ozone over four sub-regions of the southern hemispheric tropospheric ozone maximum (SHTOM) over a 20-year period. Our study is based on hindcast simulations from the National Aeronautics and Space Administration Global Modeling Initiative chemistry transport model (NASA GMI-CTM) of tropospheric and stratospheric chemistry, driven by assimilated Modern Era Retrospective Analysis for Research and Applications (MERRA) meteorological fields. Our analysis shows that over SHTOM region, the IAV of the stratospheric contribution is the most important factor driving the IAV of upper tropospheric ozone (270 hPa), where ozone has a strong radiative effect. Over the South Atlantic region, the contribution from surface emissions to the IAV of ozone exceeds that from stratospheric input at and below 430 hPa. Over the South Indian Ocean, the IAV of stratospheric ozone makes the largest contribution to the IAV of ozone with little or no influence from surface emissions at 270 and 430 hPa in austral winter. Over the tropical South Atlantic region, the contribution from IAV of stratospheric input dominates in austral winter at 270 hPa and drops to less than half but is still significant at 430 hPa. Emission contributions are not significant at these two levels. The IAV of lightning over this region also contributes to the IAV of ozone in September and December. Over the tropical southeastern Pacific, the contribution of the IAV of stratospheric input is significant at 270 and 430 hPa in austral winter, and emissions have little influence.

Citation: Liu, J., Rodriguez, J. M., Steenrod, S. D., Douglass, A. R., Logan, J. A., Olsen, M. A., Wargan, K., and Ziemke, J. R.: Causes of interannual variability over the southern hemispheric tropospheric ozone maximum, Atmos. Chem. Phys., 17, 3279-3299, doi:10.5194/acp-17-3279-2017, 2017.
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Short summary
We quantify the relative contribution of processes controlling the interannual variability (IAV) of tropospheric ozone over the southern hemispheric tropospheric ozone maximum (SHTOM) with GMI chemistry transport model. We use various GMI tracer diagnostics, including a StratO3 tracer to quantify the stratospheric impact, and tagged CO tracers to track the emission sources. Our result shows that the stratospheric contribution is the most important factor driving the IAV of upper tropospheric O3.
We quantify the relative contribution of processes controlling the interannual variability (IAV)...
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