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Volume 16, issue 11
Atmos. Chem. Phys., 16, 7091–7103, 2016
https://doi.org/10.5194/acp-16-7091-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
Atmos. Chem. Phys., 16, 7091–7103, 2016
https://doi.org/10.5194/acp-16-7091-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.

Research article 10 Jun 2016

Research article | 10 Jun 2016

Tropospheric column ozone response to ENSO in GEOS-5 assimilation of OMI and MLS ozone data

Mark A. Olsen1,2, Krzysztof Wargan3,4, and Steven Pawson3 Mark A. Olsen et al.
  • 1Atmospheric Chemistry and Dynamics Laboratory, Code 614, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 2Goddard Earth Science, Technology and Research Center, Morgan State University, Baltimore, MD, USA
  • 3Global Modeling and Assimilation Office, Code 610.1, NASA Goddard Space Flight Center, Greenbelt, MD, USA
  • 4Science Systems and Applications Inc., Lanham, MD, USA

Abstract. We use GEOS-5 analyses of Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) ozone observations to investigate the magnitude and spatial distribution of the El Niño Southern Oscillation (ENSO) influence on tropospheric column ozone (TCO) into the middle latitudes. This study provides the first explicit spatially resolved characterization of the ENSO influence and demonstrates coherent patterns and teleconnections impacting the TCO in the extratropics. The response is evaluated and characterized by both the variance explained and sensitivity of TCO to the Niño 3.4 index. The tropospheric response in the tropics agrees well with previous studies and verifies the analyses. A two-lobed response symmetric about the Equator in the western Pacific/Indonesian region seen in some prior studies and not in others is confirmed here. This two-lobed response is consistent with the large-scale vertical transport. We also find that the large-scale transport in the tropics dominates the response compared to the small-scale convective transport. The ozone response is weaker in the middle latitudes, but a significant explained variance of the TCO is found over several small regions, including the central United States. However, the sensitivity of TCO to the Niño 3.4 index is statistically significant over a large area of the middle latitudes. The sensitivity maxima and minima coincide with anomalous anti-cyclonic and cyclonic circulations where the associated vertical transport is consistent with the sign of the sensitivity. Also, ENSO related changes to the mean tropopause height can contribute significantly to the midlatitude response. Comparisons to a 22-year chemical transport model simulation demonstrate that these results from the 9-year assimilation are representative of the longer term. This investigation brings insight to several seemingly disparate prior studies of the El Niño influence on tropospheric ozone in the middle latitudes.

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Ozone observations from instruments on NASA’s Aura satellite are used to investigate the ENSO impact on tropospheric column ozone (TCO). This study provides the first explicit spatially resolved characterization of the ENSO influence in the mid-latitudes and shows coherent patterns and connections impacting the TCO in the extratropics. The TCO response to ENSO is large enough over some midlatitude regions that it must be considered when attributing the sources of variability and trends in TCO.
Ozone observations from instruments on NASA’s Aura satellite are used to investigate the ENSO...
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