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第 285 回 大気海洋物理系 B 棟コロキウム のおしらせ

日　時：2022/10/19(水) 14:00 -- 15:00

ツール：Zoom

発表者：郭 諄郿

題　目：Annual and Inter-annual Variations of Surface Ozone in Sapporo, Japan

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Annual and Inter-annual Variations of Surface Ozone in Sapporo, Japan（郭 諄郿）発表要旨：

        Past studies on the seasonality of surface ozone in Sapporo and across
        Japan had both shown a springtime maximum and summertime minimum. 
        Despite the increased solar insolation that facilitates photochemical 
        production in summertime, the minimum is mainly driven by the domination 
        of oceanic airmass that brings less polluted air, while in other seasons 
        the area  is mainly dominated by polluted continental airmass (Yamaji et 
        al., 2006).
        
        Initial analysis of surface ozone in Sapporo using NIES data from 2000 
        to 2019 showed a similar seasonal pattern, but also with high and 
        largely distributed ozone data during springtime. In addition, 
        relatively high nighttime levels in spring reflect a higher frequency of 
        pollution regimes.
        It is suspected that long range transport of polluted air from the Asian 
        continent causes such observations, which also supported by the high 
        wind speed data in spring in Sapporo, and is consistent with the 
        transport patterns by past studies - analysis and modelling by Yamaji et 
        al., 2006, and trajectory analysis by Pochanart et al.2002 showed 
        dominant eastward regional-scale airmass transport from Eurasian 
        continent  towards Japan.
        
        To investigate the long range transport and its domination on springtime 
        ozone in Japan, trajectory analysis is being carried out using JRA-55 
        reanalysis datasets by the Japan Meteorological Agency to analyze the 
        transport patterns, focusing on the period of 2010-2022. As past studies 
        on surface ozone mainly focused on data before 2010, this will help 
        extend the previous understanding to recent days, especially the 
        patterns and possible changes under climate change. Also, past studies 
        on seasonality of surface ozone in Sapporo focused on photochemistry, 
        but other studies have shown that long-range transport and meteorology 
        are also large factors behind the variations, so this research also aims 
        to understand such effects. The results are not limited to Sapporo and 
        might also extend to the whole of Japan in facilitating the 
        understanding of surface ozone pollution across the nation.
        
        
        
    

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