[A-CG46] Science in the Arctic Region

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

*Teppei J Yasunari^1,2, Daiju Narita³, Toshihiko Takemura⁴, Shigeto Wakabayashi⁵, Akira Takeshima⁶ (1.Arctic Research Center, Hokkaido University, 2.Center for Natural Hazards Research, Hokkaido University, 3.Graduate School of Arts and Sciences, The University of Tokyo, 4.Research Institute for Applied Mechanics (RIAM), Kyushu University, 5.School of Engineering, Hokkaido University, 6.Department of Civil Engineering, The University of Tokyo)

Keywords:wildfire, aerosol, air quality, health impact, climate change, global climate model

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, PM_2.5 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 PM_2.5 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