09:30 〜 09:45
[AAS11-09] Annual and Inter-annual variations of Surface Ozone in Sapporo
キーワード：大気化学、大気汚染、対流圏オゾン、コロナ
Introduction
Surface ozone in Sapporo varies dynamically seasonally according to the meteorological conditions, namely (i) solar radiation which affects the photochemical production of ozone; (ii) regional-scale airflow, particularly the East Asian Monsoon, which affects the transport of ozone and its precursors. The general variation is characterized by a high peak in spring and lower peak in autumn, and lows in summer and winter [1][2].
Inter-annually, surface ozone showed a general increase from 1980 to 2010 [3].
Annual and inter-annual variations
Analysis on surface ozone annual variability in Sapporo using Sapporo Kokusetsu station data from the National Institute for Environmental Studies (NIES) and Hokkaido Research Organization (HRO) showed a high peak and large variability in spring corresponding to the transport of pollutants and precursors from the continent. Summer low corresponding to maritime airflow, and winter low due to scarce sunlight inhibiting photochemical production were also observed. This result aligns with past seasonal variations.
For inter-annual variations, the increase of ozone had continued to increase, but less rapidly, during 2011~2024.
Effects of COVID-19
In Fig. 1, the COVID-19 situation during 2020~2022 is marked by the yellow background. Ozone has been reported to not show any significant drop despite the lower emission of precursors [4]. However, Fig. 1 shows that the amplitude of seasonal variations during 2020~2022 have been noticeably smaller compared to the past 10 years, especially during 2020 when lockdowns had just started.
Difference between Center and Kokusetsu Stations
Data from the Sapporo Center station, located at the city-centre of Sapporo, was originally used. However, the OX concentrations were found to be particularly low among all stations in Sapporo city. In Fig. 2 we compare OX data at Sapporo Center (43°3’44” N 141°21’15” E) to Sapporo Kokusetsu (43°4’54” N 141°20’0” E) from years 2010~2024, and differences are plotted in Fig. 3. The two stations are around 2.7 km apart. Discussions further into this issue will be made during the presentation.
References
[1] Pochanart et al., 2002, Atmospheric Environment, Volume 36, Issue 26, 2002, 4235-4250.
[2] Yamaji et al., 2006, Atmospheric Environment, Volume 40, Issue 10, 2006, 1856-1868.
[3] Yamaguchi et al., 2012, Kankyou kagaku kenkyuu senta zyohou 2-gou, HRO, 29-34.
[4] Ministry of Environment, https://www.env.go.jp/council/07air-noise/y078-12/900427201.pdf, (accessed on 2025/1)
[5] Kwok, 2023, Master’s Thesis, Graduate School of Environmental Science, Hokkaido University.
Surface ozone in Sapporo varies dynamically seasonally according to the meteorological conditions, namely (i) solar radiation which affects the photochemical production of ozone; (ii) regional-scale airflow, particularly the East Asian Monsoon, which affects the transport of ozone and its precursors. The general variation is characterized by a high peak in spring and lower peak in autumn, and lows in summer and winter [1][2].
Inter-annually, surface ozone showed a general increase from 1980 to 2010 [3].
Annual and inter-annual variations
Analysis on surface ozone annual variability in Sapporo using Sapporo Kokusetsu station data from the National Institute for Environmental Studies (NIES) and Hokkaido Research Organization (HRO) showed a high peak and large variability in spring corresponding to the transport of pollutants and precursors from the continent. Summer low corresponding to maritime airflow, and winter low due to scarce sunlight inhibiting photochemical production were also observed. This result aligns with past seasonal variations.
For inter-annual variations, the increase of ozone had continued to increase, but less rapidly, during 2011~2024.
Effects of COVID-19
In Fig. 1, the COVID-19 situation during 2020~2022 is marked by the yellow background. Ozone has been reported to not show any significant drop despite the lower emission of precursors [4]. However, Fig. 1 shows that the amplitude of seasonal variations during 2020~2022 have been noticeably smaller compared to the past 10 years, especially during 2020 when lockdowns had just started.
Difference between Center and Kokusetsu Stations
Data from the Sapporo Center station, located at the city-centre of Sapporo, was originally used. However, the OX concentrations were found to be particularly low among all stations in Sapporo city. In Fig. 2 we compare OX data at Sapporo Center (43°3’44” N 141°21’15” E) to Sapporo Kokusetsu (43°4’54” N 141°20’0” E) from years 2010~2024, and differences are plotted in Fig. 3. The two stations are around 2.7 km apart. Discussions further into this issue will be made during the presentation.
References
[1] Pochanart et al., 2002, Atmospheric Environment, Volume 36, Issue 26, 2002, 4235-4250.
[2] Yamaji et al., 2006, Atmospheric Environment, Volume 40, Issue 10, 2006, 1856-1868.
[3] Yamaguchi et al., 2012, Kankyou kagaku kenkyuu senta zyohou 2-gou, HRO, 29-34.
[4] Ministry of Environment, https://www.env.go.jp/council/07air-noise/y078-12/900427201.pdf, (accessed on 2025/1)
[5] Kwok, 2023, Master’s Thesis, Graduate School of Environmental Science, Hokkaido University.