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第359回 大気海洋物理学・気候力学セミナー のおしらせ

日 時:1月20日 (木) 9:30 - 12:00
Date :Thu., 20 Jan 9:30 - 12:00
ツール:Zoom (Online)
Tool :Zoom (Online)

注意事項 :Zoomのミーティング情報が必要な場合は下記のメールアドレスまでお問い合わせください。
Note :If you need Zoom meeting information, please contact us at the email address below.

発表者:Yuan Nan(大気海洋物理学・気候力学コース/D3)
Speaker:Yuan Nan (Faculty of Environmental Earth Science/D3)
Title:Cross-shelf overturning in geostrophic-stress-dominant coastal fronts­

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Cross-shelf overturning in geostrophic-stress-dominant coastal fronts
Yuan Nan(大気海洋物理学・気候力学コース/D3)
発表要旨:

Compared to the dynamics of the predominantly geostrophic along-shelf current, our understanding of the cross-shelf dynamics is inadequate, despite their importance in water mixing and nutrient entrainment. We investigated the cross-shelf overturning along the East Sakhalin Current in the Okhotsk Sea, which is a source of nutrients such as iron for the western North Pacific. Here we reveal that the cross-shelf circulation during winter is characterised by nearshore upwelling and shelf-break downwelling under downwelling-favourable monsoon wind, contrary to a classical Ekman overturning (EOT). This reverse EOT is driven by the internal stress, caused by an intensive vertical mixing and geostrophic vertical shear in the shelf-break front, produced by the riverine discharges from the far-eastern Eurasian Continent. The EOT blocks the Ekman onshore transport from the open ocean, thereby producing a deep mixed layer at the shelf break. Scaling analyses indicate the applicability of this mechanism to various other shelf-break fronts.

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連絡先

安成 哲平
mail-to: t.j.yasunari__at__arc.hokudai.ac.jp
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