Journal of Oceanography

, Volume 62, Issue 4, pp 481–492 | Cite as

Seasonal variations of the upper ocean in the western north pacific observed by an argo float

  • Naoto Iwasaka
  • Fumiaki Kobashi
  • Yosuke Kinoshita
  • Yuko Ohno
Original Article


A seasonal evolution of surface mixed layer in the western North Pacific around 24°N between 143°E and 150°E was observed by using an Argo float for more than 9 months, from December 2001 through August 2002. The result showed that the mixed layer deepened gradually in the first two months. It reached its maximum depth of about 130 m at the end of January, after which the mixed layer varied largely and sometimes the pycnocline below the mixed layer was much weakened until the summer mixed layer formed in late April. The thin surface mixed layer was maintained during the rest of the observation period. Heat budget analysis suggests that the vertical and horizontal temperature advections are the two most dominant terms in the heat balance in the upper layer on time scales from a few days to a month. The vertical motions that are possibly responsible for the vertical temperature advection are discussed.


Argo float observation oceanic mixed layer heat balance internal tide barotropic response 


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Copyright information

© The Oceanographic Society of Japan/TERRAPUB/Springer 2006

Authors and Affiliations

  • Naoto Iwasaka
    • 1
    • 2
  • Fumiaki Kobashi
    • 2
  • Yosuke Kinoshita
    • 2
  • Yuko Ohno
    • 2
  1. 1.Institute of Observational Research for Global ChangeJAMSTECNatsushima-cho, Yokosuka, KanagawaJapan
  2. 2.Department of Marine TechnologyTokyo University of Marine Science and TechnologyEtchujima, Koto-ku, TokyoJapan

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