[A-AS07] 成層圏・対流圏過程とその気候への影響

[AAS07-02] 2016年QBO崩壊に対するエルニーニョと海氷の影響

★招待講演

*廣田 渚郎¹、塩竈 秀夫¹、秋吉 英治¹、小倉 知夫¹、高橋 正明¹、河谷 芳雄²、木本 昌秀³、森 正人⁴ (1.国立研究開発法人　国立環境研究所、2.国立研究開発法人　海洋研究開発機構、3.東京大学　大気海洋研究所、4.東京大学　先端技術研究センター)

キーワード：QBO、エルニーニョ、海氷、大気モデル

The westerly phase of the quasi-biennial oscillation (QBO) was unexpectedly disrupted by an anomalous easterly near 40 hPa (~23 km) in February 2016. At the same time, a very strong El Nino and a very low Arctic sea-ice concentration in the Barents and Kara Sea were present. Previous studies have shown that the disruption of the QBO was primarily caused by the momentum transport of the atmospheric waves in the Northern Hemisphere. Our results indicate that the tropical waves evident over the Atlantic, Africa, and the western Pacific were associated with extratropical disturbances. Moreover, we suggest that the El Nino and sea-ice anomalies in 2016 account for approximately half of the disturbances and waves based on multiple regression analysis of the observational/reanalysis data and large-ensemble experiments using an atmospheric global climate model.