Assessment of mean world ocean meridional heat transport characteristics by a high-resolution model

Abstract

Eddy-induced meridional heat transport (EMHT) distribution in the world ocean is calculated by means of the eddy-resolving model INMIO, with atmospheric and radiative forcing defined by the CORE-II protocol data in 1978-1982. The EMHT is defined as the deviation of the total MHT value from the one calculated on the basis of 3-month running means of temperature and velocity. Local and zonally-integrated distributions of the EMHT in the global ocean and its basins are considered. We show that in some locations the eddy component makes a significant contribution to the total MHT, particularly in the Southern Ocean, near the equator, in western boundary currents, and in the regions of current confluences. Several qualitative differences are found between our results and other model-based and observation-based assessments. The eddy heat transport is shown to have sometimes a positive component along the horizontal temperature gradient direction, which makes it ill-founded to parameterize the EMHT by the common heat diffusion law with a positive diffusion coefficient.