Journal of Oceanography

, Volume 62, Issue 4, pp 587–596 | Cite as

Velocity structures and transports of the Kuroshio and the Ryukyu current during fall of 2000 estimated by an inverse technique

Short Contribution

Abstract

An inverse calculation using hydrographic section data collected from October to December 2000 yields velocity structure and transports of the Kuroshio in the Okinawa Trough region of the East China Sea (ECS) and south of central Japan, and of the Ryukyu Current (RC) southeast of the Ryukyu Islands. The results show the Kuroshio flowing from the ECS, through the Tokara Strait (TK), with a subsurface maximum velocity of 89 cm s−1 at 460 dbar. In a section (TI) southeast of Kyushu, a subsurface maximum velocity of 92 cm s−1 at 250 dbar is found. The results also show the RC flowing over the continental slope from the region southeast of Okinawa (OS) to the region east of Amami-Ohshima (AE) with a subsurface maximum velocity of 67 cm s−1 at 400 dbar, before joining the Kuroshio southeast of Kyushu (TI). The volume transport around the subsurface velocity maximum southeast of Kyushu (TI) balances well with the sum of those in TK and AE. The temperature-salinity relationships found around these velocity cores are very similar, indicating that the same water mass is involved. These results help demonstrate the joining of the RC with the Kuroshio southeast of Kyushu. The net volume transport of the Kuroshio south of central Japan is estimated to be 64∼79 Sv (1 Sv ≡ 106 m3s−1), of which 27 Sv are supplied by the Kuroshio from the ECS and 13 Sv are supplied by the RC from OS. The balance (about 24∼39 Sv) is presumably supplied by the Kuroshio recirculation south of Shikoku, Japan.

Keywords

Kuroshio Ryukyu Current inverse technique subsurface velocity core volume transport 

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Copyright information

© The Oceanographic Society of Japan/TERRAPUB/Springer 2006

Authors and Affiliations

  1. 1.Institute of Observational Research for Global Change/JAMSTECNatsushima-cho, YokosukaJapan
  2. 2.State Key Laboratory of Satellite Ocean Environment Dynamics, Second Institute of OceanographyState Oceanic AdministrationHangzhouChina
  3. 3.Graduate School of OceanographyUniversity of Rhode IslandNarragansettUSA
  4. 4.Nagasaki Marine ObservatoryJapan Meteorological AgencyNagasakiJapan

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