Climate Dynamics

, Volume 33, Issue 4, pp 565–589

Observed freshening and warming of the western Pacific Warm Pool

  • Sophie Cravatte
  • Thierry Delcroix
  • Dongxiao Zhang
  • Michael McPhaden
  • Julie Leloup
Article

DOI: 10.1007/s00382-009-0526-7

Cite this article as:
Cravatte, S., Delcroix, T., Zhang, D. et al. Clim Dyn (2009) 33: 565. doi:10.1007/s00382-009-0526-7

Abstract

Trends in observed sea surface salinity (SSS) and temperature are analyzed for the tropical Pacific during 1955–2003. Since 1955, the western Pacific Warm Pool has significantly warmed and freshened, whereas SSS has been increasing in the western Coral Sea and part of the subtropical ocean. Waters warmer than 28.5°C warmed on average by 0.29°C, and freshened by 0.34 pss per 50 years. Our study also indicates a significant horizontal extension of the warm and fresh surface waters, an expansion of the warm waters volume, and a notable eastward extension of the SSS fronts located on the equator and under the South Pacific Convergence Zone. Mixed layer depth changes examined along 137°E and 165°E are complex, but suggest an increase in the equatorial barrier layer thickness. Our study also reveals consistency between observed SSS trends and a mean hydrological cycle increase inferred from Clausius–Clapeyron scaling, as predicted under global warming scenarios. Possible implications of these changes for ocean–atmosphere interactions and El Niño events are discussed.

Keywords

Western tropical Pacific Warm Pool Sea surface salinity Hydrological cycle Decadal variability Long-term trend 

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  • Sophie Cravatte
    • 1
  • Thierry Delcroix
    • 1
  • Dongxiao Zhang
    • 2
  • Michael McPhaden
    • 2
  • Julie Leloup
    • 3
  1. 1.IRD/LEGOSToulouseFrance
  2. 2.NOAA/PMELSeattleUSA
  3. 3.RSMAS/MPOUniversity of MiamiMiamiUSA

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