論文

査読有り
2015年4月

Interdecadal decrease of the Oyashio transport on the continental slope off the southeastern coast of Hokkaido, Japan

JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
  • Hiroshi Kuroda
  • ,
  • Taku Wagawa
  • ,
  • Yugo Shimizu
  • ,
  • Shin-ichi Ito
  • ,
  • Shigeho Kakehi
  • ,
  • Takashi Okunishi
  • ,
  • Sosuke Ohno
  • ,
  • Akira Kusaka

120
4
開始ページ
2504
終了ページ
2522
記述言語
英語
掲載種別
研究論文(学術雑誌)
DOI
10.1002/2014JC010402
出版者・発行元
AMER GEOPHYSICAL UNION

We investigated the interdecadal trend of Oyashio velocity and transport during 1993-2011 based mainly on linear trend analysis of altimetry and in situ temperature-salinity data from a monitoring line (A-line) off the southeastern Hokkaido coast. Significant trends of increasing sea level were detected on the continental slope, north of the Kuril-Kamchatka Trench. Sea level anomaly data revealed a localized clockwise circulation centered near the trench, the suggestion being that the strength of the Oyashio on the slope and the offshore return flow had decreased. The Oyashio mainstream seemed to have shifted from a nearshore to an offshore path. Steric heights estimated from the A-line data exhibited an increasing trend north of the trench, where 50-80% of the increase was determined by halosteric components attributable to a trend of decreasing salinity in the subsurface. The trend of decreasing salinity was related to downward displacement of isohaline/isopycnal surfaces. The largest displacement was above the trench. Horizontal pressure gradients associated with southwestward flows on the slope were weakened. The Oyashio transport decreased by 8.9 Sv (10(6) m(3) s(-1)) in 19 years. A mesoscale eddy analysis revealed that clockwise eddies appeared more frequently in recent years near the trench around the A-line and could decrease the Oyashio transport. A baroclinic, long Rossby-wave model also predicted that a large-scale baroclinic response to the wind stress could weaken the Oyashio velocity in the upper layer. Dynamical linkage between the localized eddies and large-scale response remains to be clarified in future work.

Web of Science ® 被引用回数 : 12

リンク情報
DOI
https://doi.org/10.1002/2014JC010402
Web of Science
https://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcAuth=JSTA_CEL&SrcApp=J_Gate_JST&DestLinkType=FullRecord&KeyUT=WOS:000354417200007&DestApp=WOS_CPL

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