JpGU-AGU Joint Meeting 2017

講演情報

[EE]Evening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-AS07] [EE] Aerosol impacts on air quality and climate

2017年5月22日(月) 17:15 〜 18:30 ポスター会場 (国際展示場 7ホール)

[AAS07-P11] 酸化鉄エアロゾルの単一粒子測定法の確立と放射影響の評価

*吉田 淳1茂木 信宏1大畑 祥1足立 光司2森 樹大1小池 真1高見 昭憲3 (1.東京大学大学院理学系研究科、2.気象研究所、3.国立環境研究所)

キーワード:aerosol, iron oxide, atmospheric radiation, observation

Iron oxide (FeOx) aerosols efficiently absorb solar radiation, causing a perturbation of radiation balance. A well-known FeOx aerosol is mineral dust, emitted from the erosion of arid and semi-arid soils. In addition to dust (natural FeOx), anthropogenic FeOx aerosols generated through combustion process have been reported recently. However, the size-resolved concentration of FeOx aerosols are not well understood because of the technical difficulty of single-particle measurement of FeOx particle. Furthermore, the importance of anthropogenic FeOx aerosols to climate has never been focused on. In this study, we performed ground observation of FeOx aerosols at Cape Hedo Atmosphere and Aerosol Monitoring Station (CHAAMS), Japan. We used a modified single-particle soot photometer (SP2) and transmission electron microscopy (TEM). Although the SP2 is conventionally used to measure individual black carbon (BC) particles, we applied it to measure FeOx aerosols using a new method (Yoshida et al., 2016).
Optical properties of FeOx aerosols obtained by the SP2 and TEM show that the majority of FeOx aerosols were of anthropogenic origin. The mean mass concentration was 40.4 ng/m3, approximately one third of that of BC (132 ng/m3). We also theoretically estimated shortwave absorption of these aerosols using the size-resolved concentration observed by the SP2. The absorbing heating power of FeOx aerosols is estimated to be 2.3–6.4% of that of BC. This result indicates that anthropogenic FeOx aerosols, which has thus far not received attention, can have non-negligible light-absorbing ability comparting with brown carbon and mineral dust, well known light-absorbing aerosols.