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The response of tropical tropospheric ozone to ENSO
Author(s) -
Oman L. D.,
Ziemke J. R.,
Douglass A. R.,
Waugh D. W.,
Lang C.,
Rodriguez J. M.,
Nielsen J. E.
Publication year - 2011
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2011gl047865
Subject(s) - troposphere , climatology , ozone , tropospheric ozone , walker circulation , environmental science , atmospheric sciences , el niño southern oscillation , sea surface temperature , atmospheric circulation , geology , meteorology , geography
We have successfully reproduced the Ozone ENSO Index (OEI) in the Goddard Earth Observing System (GEOS) chemistry‐climate model (CCM) forced by observed sea surface temperatures over a 25‐year period. The vertical ozone response to ENSO is consistent with changes in the Walker circulation. We derive the sensitivity of simulated ozone to ENSO variations using linear regression analysis. The western Pacific and Indian Ocean region shows similar positive ozone sensitivities from the surface to the upper troposphere, in response to positive anomalies in the Niño 3.4 Index. The eastern and central Pacific region shows negative sensitivities with the largest sensitivity in the upper troposphere. This vertical response compares well with that derived from SHADOZ ozonesondes in each region. The OEI reveals a response of tropospheric ozone to circulation change that is nearly independent of changes in emissions and thus it is potentially useful in chemistry‐climate model evaluation.