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| Titel |
Global ozone–CO correlations from OMI and AIRS: constraints on tropospheric ozone sources |
| VerfasserIn |
P. S. Kim, D. J. Jacob, X. Liu, J. X. Warner, K. Yang, K. Chance, V. Thouret, P. Nédélec |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1680-7316
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 18 ; Nr. 13, no. 18 (2013-09-17), S.9321-9335 |
| Datensatznummer |
250085702
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| Publikation (Nr.) |
 copernicus.org/acp-13-9321-2013.pdf |
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| Zusammenfassung |
| We present a global data set of free tropospheric ozone–CO correlations with
2° × 2.5° spatial resolution from the Ozone Monitoring
Instrument (OMI) and Atmospheric Infrared Sounder (AIRS) satellite
instruments for each season of 2008. OMI and AIRS have near-daily global
coverage of ozone and CO respectively and observe coincident scenes with
similar vertical sensitivities. The resulting ozone–CO correlations are
highly statistically significant (positive or negative) in most regions of
the world, and are less noisy than previous satellite-based studies that
used sparser data. Comparison with ozone–CO correlations and regression
slopes (dO3/dCO) from MOZAIC (Measurements of OZone, water vapour, carbon monoxide and
nitrogen oxides by in-service AIrbus airCraft) aircraft profiles shows good general
agreement. We interpret the observed ozone–CO correlations with the
GEOS (Goddard Earth Observing System)-Chem chemical transport model to infer constraints on ozone sources.
Driving GEOS-Chem with different meteorological fields generally shows
consistent ozone–CO correlation patterns, except in some tropical regions
where the correlations are strongly sensitive to model transport error
associated with deep convection. GEOS-Chem reproduces the general structure
of the observed ozone–CO correlations and regression slopes, although there
are some large regional discrepancies. We examine the model sensitivity of
dO3/dCO to different ozone sources (combustion, biosphere, stratosphere,
and lightning NOx) by correlating the ozone change from that source to
CO from the standard simulation. The model reproduces the observed positive
dO3/dCO in the extratropical Northern Hemisphere in spring–summer, driven
by combustion sources. Stratospheric influence there is also associated with
a positive dO3/dCO because of the interweaving of stratospheric
downwelling with continental outflow. The well-known ozone maximum over the
tropical South Atlantic is associated with negative dO3/dCO in the
observations; this feature is reproduced in GEOS-Chem and supports a
dominant contribution from lightning to the ozone maximum. A major model
discrepancy is found over the northeastern Pacific in summer–fall where
dO3/dCO is positive in the observations but negative in the model, for
all ozone sources. We suggest that this reflects a model overestimate of
lightning at northern midlatitudes combined with an underestimate of the
East Asian CO source. |
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