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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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