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Titel |
Influence of meteorological variability on interannual variations of springtime boundary layer ozone over Japan during 1981–2005 |
VerfasserIn |
J. Kurokawa, T. Ohara, I. Uno, M. Hayasaki, H. Tanimoto |
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 ; 9, no. 17 ; Nr. 9, no. 17 (2009-09-01), S.6287-6304 |
Datensatznummer |
250007600
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Publikation (Nr.) |
copernicus.org/acp-9-6287-2009.pdf |
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Zusammenfassung |
We investigated the influence of meteorological variability on the
interannual variation of springtime boundary layer ozone over Japan during
1981–2005 by multiyear simulations with the Models-3 Community Multiscale
Air Quality (CMAQ) modeling system and the Regional Emission Inventory in
Asia (REAS). CMAQ/REAS generally reproduced the observed interannual
variability of springtime ozone over Japan, showing
year-to-year variations larger than the annual rate of
increase of the long-term trend. We then analyzed the influence of the
interannual variation of meteorology in simulated results by using the fixed
emissions for 2000 and meteorological fields for each year. As a reference
parameter, we calculated the area-weighted surface pressure anomaly over the
Pacific Ocean east of Japan. When the anomaly has a large negative value,
polluted air masses from continental Asia tend to be transported directly to
Japan by westerly winds. In contrast, when the anomaly has a large positive
value, influence of the outflow from continental Asia tends to be small
because the westerly components of wind fields around Japan are
comparatively weak. Instead, southerly winds are relatively strong and
transport clean air masses from the Pacific Ocean to Japan. Consequently,
springtime ozone over Japan is higher (lower) than in ordinary years when
the anomaly has a large negative (positive) value. In general, the
interannual variation of springtime ozone over Japan is sensitive to the
outflow from continental Asia. We also found some correlation between
springtime ozone over Japan and the El Niño-Southern Oscillation,
indicating that higher and lower springtime ozone over Japan are related to
La Niña and El Niño, respectively. Differences in the meridional
displacement and diversity of cyclone tracks near Japan between El Niño
and La Niña years may be responsible for interannual variations in the
springtime boundary layer ozone over Japan. |
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