Analysis of Relationship between Meteorological Conditions and Ground O3 Levels in Summer Over the Central Kanto Area

The increasing trend in ground ozone (O3) concentration has recently been recognized in Japan, though concentrations of ozone precursors have been decreased. It is well known the status of atmospheric has been changing on a long term, not only over the world, but also in Japan. Therefore, one of causes is possibly imagined that is the effect of meteorological conditions. In order to confirm whether the change of meteorological conditions contribute to the Japanese O3 trend we examine the relationship between meteorological factors (e.g., temperature, wind speed) and ground O3 levels concentration over the central Kanto area of Japan using both statistical analysis and numerical models. The nested grid system of numerical experiments which cover a region of Kanto with grid resolutions of 9 km, 3 km, and 1 km respectively, have been employed in this study. The results of analysis show there are close relationships between meteorological conditions and the peak O3 and changes in meteorological conditions may be one of causes leading to the rising O3 concentration levels in this area.