Pure and Applied Geophysics

, Volume 169, Issue 3, pp 579–594 | Cite as

Barrier Layer and Relevant Variability of the Salinity Field in the Equatorial Pacific Estimated in an Ocean Reanalysis Experiment



This paper investigates the feasibility of an ocean data assimilation system to analyze the salinity variability associated with the barrier layer in the equatorial Pacific. In order to validate reproducibility of the temperature and salinity fields, we perform an assimilation run where some temperature and salinity observations by TRITON buoys and Argo floats are withheld. The assimilation run reproduces interannual variability of salinity in the equatorial Pacific exhibited in the data that are withheld. Statistics shows that salinity values and variations in the assimilation run are closer to the data than the climatology and in the model free run. We also confirm that zonal currents in the equatorial Pacific in the reanalysis, where all available temperature and salinity data are assimilated, are consistent with an observation-based mapping and the data of the Acoustic Doppler Current Profiler mounted on TAO buoys. Variability of the barrier layer and relevant salinity field in the reanalysis is consistent with former studies. A thick barrier layer area generally exists west of the equatorial salinity front and is displaced zonally with the migration of the front in the response to El Niño-Southern Oscillation, although the area moved to the east over the front in the 1997 El Niño. It is confirmed that the barrier layer thickness is closely correlated with the near-surface temperature in the equatorial Pacific.



We would like to thank Dr. T. Yasuda for providing us the OGCM used in the data assimilation system. We also thank anomalous reviewers for helpful comments. This study was partly supported by the Grant-in-Aids for Science Research 19540469 from the Ministry of Education, Culture, Sports, Science and Technology, Japan.


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Copyright information

© Springer Basel AG 2011

Authors and Affiliations

  • Y. Fujii
    • 1
  • M. Kamachi
    • 1
  • S. Matsumoto
    • 2
  • S. Ishizaki
    • 2
  1. 1.Oceanographic Research DepartmentMeteorological Research InstituteTsukubaJapan
  2. 2.Global Environment and Marine DepartmentJapan Meteorological AgencyTokyoJapan

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