Atmos. Chem. Phys. Discuss., 9, 7555-7588, 2009
www.atmos-chem-phys-discuss.net/9/7555/2009/
doi:10.5194/acpd-9-7555-2009
© Author(s) 2009. This work is distributed
under the Creative Commons Attribution 3.0 License.
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This discussion paper has been under review for the journal Atmospheric Chemistry and Physics (ACP). Please refer to the corresponding final paper in ACP.
Influence of meteorological variability on interannual variations of the springtime boundary layer ozone over Japan during 1981–2005
J. Kurokawa1, T. Ohara1, I. Uno2, M. Hayasaki3, and H. Tanimoto1
1National Institute for Environmental Studies, Onogawa, Tsukuba, Ibaraki, Japan
2Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka, Japan
3Center for Environmental Remote Sensing, Chiba University, Yayoi, Inage, Chiba, Japan

Abstract. We investigated the influence of meteorological variability on the interannual variation of the 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 meteorological fields in simulated results by using the fixed emissions for 2000 and meteorology data 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, the influences 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.

Citation: Kurokawa, J., Ohara, T., Uno, I., Hayasaki, M., and Tanimoto, H.: Influence of meteorological variability on interannual variations of the springtime boundary layer ozone over Japan during 1981–2005, Atmos. Chem. Phys. Discuss., 9, 7555-7588, doi:10.5194/acpd-9-7555-2009, 2009.
 
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