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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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