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Titel |
Ozone-enhanced layers in the troposphere over the equatorial Pacific Ocean and the influence of transport of midlatitude UT/LS air |
VerfasserIn |
H. Hayashi, K. Kita, S. Taguchi |
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 ; 8, no. 10 ; Nr. 8, no. 10 (2008-05-19), S.2609-2621 |
Datensatznummer |
250006140
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Publikation (Nr.) |
copernicus.org/acp-8-2609-2008.pdf |
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Zusammenfassung |
Occurrence of ozone (O3)-enhanced layers in the troposphere over the
equatorial Pacific Ocean and their seasonal variation were investigated
based on ozonesonde data obtained at three Southern Hemisphere ADditional
OZonesondes (SHADOZ) sites, Watukosek, American Samoa and San Cristobal, for
6 years between 1998 and 2003. O3-enhanced layers were found in about
50% of observed O3 profiles at the three sites. The formation
processes of O3-enhanced layers were investigated by meteorological
analyses including backward trajectories. On numerous occasions,
O3-enhanced layers resulted from the transport of air masses affected
by biomass burning. The contribution of this process was about 30% at San
Cristobal during the periods from February to March and from August to
September, while it was relatively low, about 10%, at Watukosek and
Samoa. A significant number of the O3-enhanced layers were attributed
to the transport of midlatitude upper-troposphere and lower-stratosphere
(UT/LS) air. Meteorological analyses indicated that these layers originated
from equatorward and downward transport of the midlatitude UT/LS air masses
through a narrow region between high- and low-pressure systems around the
subtropical jet stream. This process accounted for 50–80% at Watukosek
between May and December, about 80% at Samoa on yearly average, and
40–70% at San Cristobal between November and March, indicating that it
was important for O3 budget over the equatorial Pacific Ocean. |
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