Continuous, array-based estimates of atlantic ocean heat transport at 26.5°N

W. E. Johns, M. O. Baringer, L. M. Beal, S. A. Cunningham, T. Kanzow, H. L. Bryden, J. J.M. Hirschi, J. Marotzke, C. S. Meinen, B. Shaw, R. Curry

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Abstract

Continuous estimates of the oceanic meridional heat transport in the Atlantic are derived from the Rapid ClimateChange-MeridionalOverturningCirculation(MOC) and HeatfluxArray (RAPID-MOCHA)observing system deployed along 26.5°N, for the period from April 2004 to October 2007. The basinwide meridional heat transport(MHT) is derived by combining temperature transports (relative to a common reference) from1) the Gulf Stream in the Straits of Florida; 2) the western boundary region offshore of Abaco, Bahamas; 3) the Ekman layer [derived from Quick Scatterometer (QuikSCAT) wind stresses]; and 4) the interior ocean monitored by "endpoint" dynamic height moorings. The interior eddy heat transport arising from spatial covariance of the velocity and temperature fields is estimated independently from repeat hydrographic and expendable bathythermograph (XBT) sections and can also be approximated by the array. The results for the 3.5 yr of data thus far available show a mean MHT of 1.33 ± 0.40 PW for 10-dayaveraged estimates, on which time scale a basinwide mass balance can be reasonably assumed. The associated MOC strength and variability is 18.5 ± 4.9 Sv (1 Sv = 106 m3 s-1). The continuous heat transport estimates range from a minimum of 0.2 to a maximum of 2.5 PW, with approximately half of the variance caused by Ekman transport changes and half caused by changes in the geostrophic circulation. The data suggest a seasonal cycle of the MHT with a maximum in summer (July-September) and minimum in late winter (March- April), with an annual range of 0.6 PW.Abreakdown of theMHTinto "overturning" and "gyre" components shows that the overturning component carries 88% of the total heat transport. The overall uncertainty of the annual mean MHT for the 3.5-yr record is 0.14 PW or about 10% of the mean value.

Original languageEnglish (US)
Pages (from-to)2429-2449
Number of pages21
JournalJournal of Climate
Volume24
Issue number10
DOIs
StatePublished - May 1 2011

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Keywords

  • Anomalies
  • Atlantic Ocean
  • Meridonial overturning circulation
  • Sea surface temperature
  • Transport

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Johns, W. E., Baringer, M. O., Beal, L. M., Cunningham, S. A., Kanzow, T., Bryden, H. L., Hirschi, J. J. M., Marotzke, J., Meinen, C. S., Shaw, B., & Curry, R. (2011). Continuous, array-based estimates of atlantic ocean heat transport at 26.5°N. Journal of Climate, 24(10), 2429-2449. https://doi.org/10.1175/2010JCLI3997.1