TERRAPUB Journal of Oceanography

Journal of Oceanography, Vol. 60 (No. 2), pp. 397-409, 2004

Absolute Volume Transports of the Oyashio Referred to Moored Current Meter Data Crossing the OICE

Kazuyuki Uehara1*, Shin-ichi Ito2, Hideo Miyake3, Ichiro Yasuda4, Yugo Shimizu2 and Tomowo Watanabe5

1National Research Institute of Far Seas Fisheries, Fisheries Research Agency, Shimizu-Orido, Shizuoka 424-8633, Japan
2Tohoku National Fisheries Research Institute, Fisheries Research Agency, Shiogama, Miyagi 985-0001, Japan
3Graduate School of Fisheries Science, Hokkaido University, Hakodate, Hokkaido 041-8611, Japan
4Graduate School of Science, University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113-0033, Japan
5National Research Institute of Fisheries Science, Fisheries Research Agency, Fukuura, Kanagawa-ku, Yokohama, Kanagawa 236-8648, Japan

(Received 19 February 2003; in revised form 18 August 2003; accepted 16 September 2003)

Abstract: During November 2000-June 2002, both direct current measurements from deployment of a line of five moorings and repeated CTD observations were conducted along the Oyashio Intensive observation line off Cape Erimo (OICE). All the moorings were installed above the inshore-side slope of the Kuril-Kamchatka Trench. Before calculating the absolute volume transports, we compared vertical velocity differences of relative geostrophic velocities with those of the measured velocities. Since both the vertical velocity differences concerned with the middle three moorings were in good agreement, the flows above the continental slope are considered to be in thermal wind balance. We therefore used the current meter data of these three moorings, selected among all five moorings, to estimate the absolute volume transports of the Oyashio referred to the current meter data. As a result, we estimated that the southwestward absolute volume transports in 0-1000 db are 0.5-12.8 106 m3/sec and the largest transport is obtained in winter, January 2001. The Oyashio absolute transports in January 2001, crossing the OICE between 42°N and 41°15´ N from the surface to near the bottom above the continental slope, is estimated to be at least 31 106 m3/sec.

*Corresponding author E-mail: kuehara@fra.affrc.go.jp

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