日本地球惑星科学連合2023年大会

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[J] 口頭発表

セッション記号 A (大気水圏科学) » A-CG 大気海洋・環境科学複合領域・一般

[A-CG46] 北極域の科学

2023年5月24日(水) 15:30 〜 16:45 103 (幕張メッセ国際会議場)

コンビーナ:両角 友喜(国立環境研究所)、島田 利元(宇宙航空研究開発機構)、堀 正岳(東京大学大気海洋研究所)、川上 達也(北海道大学)、座長:堀 正岳(東京大学大気海洋研究所)、両角 友喜(国立環境研究所)

15:30 〜 15:45

[ACG46-11] MIROC5 sensitivity experiments on increasing Siberian wildfires. Part I: impacts on aerosols, air quality, and climate

*安成 哲平1,2成田 大樹3竹村 俊彦4、若林 成人5、竹島 滉6 (1.北海道大学 北極域研究センター、2.北海道大学 広域複合災害研究センター、3.東京大学 大学院総合文化研究科、4.九州大学 応用力学研究所、5.北海道大学 大学院工学院、6.東京大学 大学院社会基盤学専攻)

キーワード:森林火災、エアロゾル、大気質、健康影響、気候変動、全球気候モデル

Recently, we often see much news of wildfires picked up in different media, and wildfire has become of considerable concern worldwide. Although there are many wildfire sources, the Siberian wildfire is one of the well-known ones. In this presentation, we introduce our recently submitted paper (Yasunari et al., submitted) on the global sensitivity simulations by a Japanese global climate model (GCM), MIROC5, at the present and future climate conditions to assess the impacts of increasing Siberian wildfire activities on atmospheric aerosols, air quality, climate, and socioeconomics. In this presentation, we show the first three impacts. Then, another presentation by Daiju Narita et al. in the same session will introduce the results of socio-economic impacts.

We run six sensitivity MIROC5/SPRINTARS simulations by each atmospheric GCM (AGCM; 15 years for spin-up and the last ten years for analyses) and coupled atmosphere and ocean GCM (AOGCM; 100 years for spin-up and the last 50 years for analyses) setting. We changed the wildfire intensities over the defined Siberian domain (control case as low emission in 2004; high emission case in 2003; very high emission case in doubling the 2003 emission) at the present (mostly 2005 settings) and future (the 2030 RCP2.6 and RCP8.5) climate conditions. In our results, we found that the increased Siberian wildfires at the present climate condition induced a broad-area cooling in the northern hemisphere from the fire source region in Siberia to the downwind regions from East Asia to North America via the North Pacific region. However, global warming effects under the two RCP scenarios exceeded the cooling effect, but the warming was statistically insignificant over the Siberian fire source region. This result was probably due to some warming suppression by the cooling effect caused by the fire smoke aerosols, even under the future climate condition.

Regarding air quality, PM2.5 increased from the fire source to the downwind regions (i.e., East Asia). The more aerosol emissions the Siberian wildfires generate, the higher percentage of exceeding the daily mean PM2.5 environment standard (25 μg m-3: WHO, 2006) we meet in those regions. We will discuss more on the day of the presentation.

References
WHO (2006), WHO Air quality guidelines for particulate matter, ozone, nitrogen dioxide and sulfur dioxide: Global update 2005. Summary of Risk Assessment. World Health Organization. https://apps.who.int/iris/handle/10665/69477