Climate Dynamics

, Volume 38, Issue 3–4, pp 513–525 | Cite as

AMOC variations in 1979–2008 simulated by NCEP operational ocean data assimilation system

  • Boyin Huang
  • Yan Xue
  • Arun Kumar
  • David W. Behringer


Variations in the Atlantic meridional overturning circulation (AMOC) between 1979 and 2008 are documented using the operational ocean analysis, the Global Ocean Data Assimilation System (GODAS), at the National Centers for Climate Prediction (NCEP). The maximum AMOC at 40°N is about 16 Sv in average with peak-to-peak variability of 3–4 Sv. The AMOC variations are dominated by an upward trend from 1980 to 1995, and a downward trend from 1995 to 2008. The maximum AMOC at 26.5°N is slightly weaker than hydrographic estimates and observations from mooring array. The dominant variability of the AMOC in 20°–65°N (the first EOF, 51% variance) is highly correlated with that in the subsurface temperature (the first EOF, 33% variance), and therefore, with density (the first EOF, 25% variance) in the North Atlantic, and is consistent with the observational estimates based on the World Ocean Database 2005. The dominant variabilities of AMOC and subsurface temperature are also analyzed in the context of possible links with the net surface heat flux, deep convection, western boundary current, and subpolar gyre. Variation in the net surface heat flux is further linked to the North Atlantic Oscillation (NAO) index which is found to lead AMOC variations by about 5 years. Our results indicate that AMOC variations can be documented based on an ocean analysis system such as GODAS.


Atlantic meridional overturning circulation AMOC Global ocean data assimilation system GODAS North Atlantic oscillation NAO National centers for environmental prediction NCEP 



Authors thank Tim Boyer of National Oceanographic Data Center for providing us objectively analyzed salinity and temperature data of the World Ocean Database 2005. Comments from two anonymous reviewers have greatly improved our manuscript.


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Copyright information

© Springer-Verlag 2011

Authors and Affiliations

  • Boyin Huang
    • 1
    • 3
  • Yan Xue
    • 1
  • Arun Kumar
    • 1
  • David W. Behringer
    • 2
  1. 1.Climate Prediction Center, NOAACamp SpringsUSA
  2. 2.Environmental Modeling Center, NOAACamp SpringsUSA
  3. 3.AshevilleUSA

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