Journal of Oceanography

, Volume 54, Issue 5, pp 465–478 | Cite as

Unusual behavior of the Kuroshio Current System from winter 1996 to summer 1997 revealed by ADEOS-OCTS and other data— Suggestion of topographically forced alternating-jet instability

  • Yoshiaki Toba
  • Hiroshi Murakami
Article
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Abstract

While the Advanced Earth Observing Satellite (ADEOS) was operating, the Kuroshio and the Kuroshio Extension, or the Kuroshio Current System, exhibited unusual behavior from the winter of 1996 to the summer of 1997. This behavior of the Kuroshio Current System has been closely studied using a time series of satellite observation images of SST and ocean color obtained by ADEOS-OCTS, reinforced by SST images obtained by NOAA-AVHRR. Our findings include (i) a long lasting, very southerly path of the Kuroshio Extension; (ii) a Kuroshio path very distant from Japan with the following alternating-jet-like north-south flow pattern of the Kuroshio Extension, which occurred twice, once in February and once in April 1997, as independent events and which was observed to be affected by the bottom topography of the Izu-Ogasawara Ridge and Trench, and of the Japan Trench; (iii) cutting off of a cold water mass after the February event; and (iv) the formation of a vortex pair after the April event. A new mechanism is suggested for the formation of the alternating-jet flow pattern: a topographically forced alternating-jet instability (AJI). An SST-Chlorophyll Diagram (T-Chl Diagram) generated using simultaneous data from a single satellite is useful for analyzing the water mass structure of this region, including biological processes.

Keywords

The Kuroshio The Kuroshio Extension ADEOS-OCTS Topographically forced alternating-jet instability (AJI) NOAA-AVHRR Bottom topography Izu-Ogasawara Ridge Vortex-pair SST-Chlorophyll Diagram (T-Chl Diagram) 
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Copyright information

© The Oceanographic Society of Japan 1998

Authors and Affiliations

  • Yoshiaki Toba
    • 1
    • 2
  • Hiroshi Murakami
    • 1
  1. 1.Earth Observation Research CenterNational Space Development Agency of Japan (EORC, NASDA)TokyoJapan
  2. 2.Japan Marine Science and Technology Center (JAMSTEC)YokosukaJapan

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