Geostrophic meridional transport in tropical Northwest Pacific based on Argo profiles

  • Zhichun Zhang (张志春)
  • Dongliang Yuan (袁东亮)
  • Peter C. Chu
Physics

Abstract

Absolute geostrophic currents in the North Pacific Ocean were calculated using P-vector method from newly gridded Argo profiling float data collected during 2004–2009. The meridional volume transport of geostrophic currents differed significantly from the classical Sverdrup balance, with differences of 10×106–20×106m3/s in the interior tropical Northwest Pacific Ocean. Analyses showed that errors of wind stress estimation could not explain all of the differences. The largest differences were found in the areas immediately north and south of the bifurcation latitude of the North Equatorial Current west of the dateline, and in the recirculation area of the Kuroshio and its extension, where nonlinear eddy activities were robust. Comparison of the geostrophic meridional transport and the wind-driven Sverdrup meridional transport in a high-resolution OFES simulation showed that nonlinear effects of the ocean circulation were the most likely reason for the differences. It is therefore suggested that the linear, steady wind-driven dynamics of the Sverdrup theory cannot completely explain the meridional transport of the interior circulation of the tropical Northwest Pacific Ocean.

Keyword

Sverdrup theory absolute geostrophic current P-vector 

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Copyright information

© Chinese Society for Oceanology and Limnology, Science Press and Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • Zhichun Zhang (张志春)
    • 1
    • 2
    • 3
  • Dongliang Yuan (袁东亮)
    • 1
    • 2
  • Peter C. Chu
    • 4
  1. 1.Institute of OceanologyChinese Academy of SciencesQingdaoChina
  2. 2.Key Laboratory of Ocean Circulation and WavesChinese Academy of SciencesQingdaoChina
  3. 3.Graduate University of Chinese Academy of SciencesBeijingChina
  4. 4.Naval Ocean Analysis and Prediction (NOAP) Laboratory, Department of OceanographyNaval Postgraduate SchoolMontereyUSA

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