TERRAPUB Journal of Oceanography
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Journal of Oceanography, Vol. 64 (No. 3), pp. 373-384, 2008

Variations of Kuroshio Geostrophic Transport South of Japan Estimated from Long-Term IES Observations

Koji Kakinoki1*, Shiro Imawaki1, Hiroshi Uchida2, Hirohiko Nakamura3, Kaoru Ichikawa1,2, Shin-ichiro Umatani1, Ayako Nishina3, Hiroshi Ichikawa2 and Mark Wimbush4

1Research Institute for Applied Mechanics, Kyushu University, Kasuga, Fukuoka 816-8150, Japan
2Japan Agency for Marine-Earth Science and Technology, Yokosuka, Kanagawa 237-0061, Japan
3Faculty of Fisheries, Kagoshima University, Kagoshima 890-0056, Japan
4Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882-1197, U.S.A.

(Received 1 November 2006; in revised form 19 August 2007; accepted 4 December 2007)

Abstract: Two inverted echo sounders were maintained on coastal and offshore sides of the Kuroshio south of Japan from October 1993 to July 2004. Applying the gravest empirical mode method, we obtained a time series of geostrophic transport. Estimated transports generally agree well with geostrophic transports estimated from hydrography. Their agreement with the hydrographic transports is better than that of transports estimated from satellite altimetry data. The geostrophic transport is expressed as the surface transport per unit depth multiplied by the equivalent depth. The geostrophic transport varies mostly with the surface transport and fractionally with the equivalent depth. Seasonal variation of the geostrophic transport has a minimum in March and a maximum in September, with a range of about one fifth of the total transport.


*Corresponding author E-mail: kakinoki@riam.kyushu-u.ac.jp


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