Estimating the geostrophic velocity obtained by HF radar observations in the upstream area of the Kuroshio

Ryoko Tokeshi, Kaoru Ichikawa, Satoshi Fujii, Kenji Sato, Shoichiro Kojima

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10 Citations (Scopus)


A method to extract geostrophic current in the daily mean HF radar data in the Kuroshio upstream region is established by comparison with geostrophic velocity determined from the along-track altimetry data. The estimated Ekman current in the HF velocity is 1.2% (1.5%) and 48° (38°)-clockwise rotated with respect to the daily mean wind in (outside) the Kuroshio. Furthermore, additional temporal smoothing is found necessary to remove residual ageostrophic currents such as the inertial oscillation. After removal of the ageostrophic components, the HF geostrophic velocity agrees well with that from the altimetry data with rms difference 0.14 (0.12) m/s in (outside) the Kuroshio.

Original languageEnglish
Pages (from-to)711-720
Number of pages10
JournalJournal of Oceanography
Issue number4
Publication statusPublished - Dec 1 2007


All Science Journal Classification (ASJC) codes

  • Oceanography

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