What Caused the Significant Increase in Atlantic Ocean Heat Content Since the mid-20th Century?

By Sang-Ki Lee

A new study led by researchers from University of Miami, NOAA-AOML, IFM-GEOMAR, and NCAR explores why the Atlantic Ocean has warmed substantially more than any other ocean basin since the 1950s. The research article published in the Geophysical Research letters evidences that the observed large warming of the Atlantic Ocean since the 1950s is largely induced by an increase in the inter-ocean heat transport from the Indian Ocean via the Agulhas leakage. The study points to an important role played by the Atlantic meridional overturning circulation (AMOC) in the South Atlantic in enhancing the secular warming of the Atlantic Ocean.

(a) Simulated pathways of the northward heat transport (contours) and heat transport vector (vectors) in the upper 3000 m for 1979-2008 obtained from the control experiment (EXP_CTR). The unit is 1x109 W/m. (b) Differences in the simulated northward heat transport (contours) and heat transport vector (vectors) between 1979-2008 and 1871-1900 periods, obtained from EXP_CTR. Red color indicates northward heat transport, while blue color indicates southward heat transport. (c) Globally averaged zonal wind stress for 1871-1900 and for 1979-2008 periods, obtained from the 20th Century Reanalysis. Image Credit: NOAA AOML.
(a) Simulated pathways of the northward heat transport (contours) and heat transport vector (vectors) in the upper 3000 m for 1979-2008 obtained from the control experiment (EXP_CTR). The unit is 1×109 W/m. (b) Differences in the simulated northward heat transport (contours) and heat transport vector (vectors) between 1979-2008 and 1871-1900 periods, obtained from EXP_CTR. Red color indicates northward heat transport, while blue color indicates southward heat transport. (c) Globally averaged zonal wind stress for 1871-1900 and for 1979-2008 periods, obtained from the 20th Century Reanalysis. Image Credit: NOAA AOML.

Lee S.-K., W. Park, E. van Sebille, M. O. Baringer, C. Wang, D. B. Enfield, S. Yeager, and B. P. Kirtman, 2011. What Caused the Significant Increase in Atlantic Ocean Heat Content Since the mid-20th Century? Geophysical Research Letters, doi:10.1029/2011GL048856. [highlighted in Oct. 6, 2011 issue of Nature as Community Choice]