[A-AS22_30PM2] 大気化学

[AAS22-05] エアロゾル・グリオキサール・ホルムアルデヒド濃度の時間変動：　詳細な誤差解析に基づいたMAX-DOAS法による観測

*入江 仁士¹、陳 誠¹、倪 聞涛¹、中山 智喜²、山崎 明宏³、高村 民雄¹、Khatri Pradeep¹ (1.千葉大学、2.名古屋大学、3.気象研究所)

キーワード：CHOCHO, HCHO, MAX-DOAS, CRDS, sky radiometer

The degradation of volatile organic compounds (VOCs) results in the formation of ozone (O₃) and secondary organic aerosols (SOA) in the troposphere. This process consists of the oxidation of VOCs by hydroxyl radical (OH), O₃, and nitrate radical (NO₃). Detailed understanding of the VOC degradation mechanism is challenged by the co-existence of vast variety of VOC species in the atmosphere. However, investigations on ubiquitous oxidation intermediates, e.g., formaldehyde (HCHO) and glyoxal (CHOCHO), can help us to test and improve the current knowledge of the VOC sources and degradation pathways.We installed one ground-based Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) system in Meteorological Research Institute (MRI) located at Tsukuba, Japan (36.06N, 130.13E) in June 2010. In addition, two more systems were installed in Chiba University at Chiba, Japan (35.63N, 140.10E) in June and December 2012, respectively. Since then, we have retrieved lower-tropospheric vertical profile information for eight components; aerosol extinction coefficients at two wavelengths, 357 and 476 nm, and NO₂, HCHO, CHOCHO, H₂O, SO₂, and O₃ concentrations. For a detailed evaluation for the aerosol retrieval, which is a key step in the MAX-DOAS eight-component retrieval, simultaneous aerosol observations with the Cavity Ring-Down Spectroscopy (CRDS) and the sky radiometer were conducted at Tsukuba on October 5-18, 2010 and September 7-18, 2012. At Chiba, in addition to the comparison with sky radiometer data, a self-consistency test was performed by comparing results obtained from two MAX-DOAS systems operated at the same place. Through these detailed evaluations, our retrieval method was improved significantly, attaining excellent agreement with CRDS and sky radiometer data. On the basis of these efforts, seasonal and diurnal temporal variations in HCHO and CHOCHO concentrations retrieved from our MAX-DOAS system are discussed in this talk.