日本地球惑星科学連合2018年大会

講演情報

[EJ] ポスター発表

セッション記号 A (大気水圏科学) » A-AS 大気科学・気象学・大気環境

[A-AS06] 大気化学

2018年5月23日(水) 13:45 〜 15:15 ポスター会場 (幕張メッセ国際展示場 7ホール)

コンビーナ:岩本 洋子(広島大学 生物圏科学研究科)、中山 智喜(長崎大学 大学院水産・環境科学総合研究科)、豊田 栄(東京工業大学物質理工学院、共同)、江口 菜穂(Kyushu University)

[AAS06-P21] Individual Particle Analysis of Marine Atmospheric Aerosols Collected over the Bering Sea and the Western North Pacific Ocean

*吉末 百花1竹谷 文一2足立 光司3岩本 洋子4森 樹大1三浦 和彦1 (1.東京理科大学、2.海洋研究開発機構、3.気象研究所、4.広島大学 生物圏科学研究科)

キーワード:海洋大気エアロゾル、ブラックカーボン、ターボール、西部北太平洋、ベーリング海、TEM-EDX

Atmospheric aerosol particles including black carbon (BC) can play a vital role in the climate change because they influence the radiative forcing on the Earth through the absorbing and scattering of solar radiation. Furthermore, it is well known that they can also affect the cloud formation by acting as cloud condensation nuclei (CCN). However, since the information of atmospheric aerosol properties is still limited, their influence on the climate change has large uncertainty. Therefore, more information of aerosol particles is required. Especially, the information of marine atmospheric aerosols is not sufficient. In this study, the morphology and chemical compositions of atmospheric aerosols over the Bering Sea and the western north Pacific Ocean were characterized by the individual particle analysis.

Observation and samplings of atmospheric aerosols were carried out during R/V MIRAI MR-16-06 cruise (2016/8/22-10/5). The ambient BC mass concentrations were measured by a single particle soot photometer (SP2). In this study, we focused on relatively high BC mass concentration events over the Bering Sea at 58.04°N, 179.29°E on 9/26/2016 and the western north Pacific Ocean at 46.05°N, 159.32°E on 9/29/2016. The atmospheric aerosols collected in both events were analyzed using a transmission electron microscope and an energy dispersive X-ray spectrometer.

The number fractions of carbon-rich (C-rich) particles were about 50% and 70% in the samples collected over the Bering Sea and the western north Pacific Ocean, respectively. The average size of C-rich particles was 0.43 μm. C-rich particles collected over the western north Pacific Ocean were mostly identified as tar balls. The backward trajectory analyses with the fire emission data suggested that the air masses of both events were affected by Siberian forest fires. The aging process of aerosol particles in the transportation will be discussed in the presentation.