Abstract
The variability of the Atlantic meridional Ocean Heat Transport (OHT) has been diagnosed from a simulation of a coupled ocean-atmosphere general circulation model, and the mechanisms responsible for this variability have been elucidated. It has been demonstrated that the interannual variability in Atlantic OHT is dominated by windstress-driven Ekman fluctuations. In contrast, the decadal and multidecadal variability is associated with the fluctuations of the Thermohaline Circulation (THC), driven by the fluctuations in deep convection over the Greenland-Iceland-Norwegian (GIN) Sea. The fluctuations of OHT induce Ocean Heat Content (OHC), and Sea Surface Temperature (SST) anomalies over the tropical and subtropical North Atlantic. The SST anomalies, in turn, have an impact on the atmosphere. The lead-lag relationships between the fluctuations of THC-related OHT and those of OHC and SST raise the possibility that a knowledge of OHT fluctuations could be used to predict variations in Atlantic Sea surface temperatures, and perhaps aspects of climate, several years in advance. A comparison of results from a second, independent, coupled model simulation is also presented, and similar conclusions reached.
Highlights
The fact that the ocean and atmosphere transport heat polewards is one of the most fundamental features of the climate system
The lower frequency variability of Atlantic Ocean Heat Transport (OHT) is associated with fluctuations in the thermohaline circulation which, in turn, are driven by fluctuations in density and deep convection in the GIN seas region (HadCM3 simulation)
The results suggest that the variations in Atlantic OHT are playing an important role in the decadal variability of the upper Atlantic Ocean
Summary
A major aim of the SINTEX project was to advance understanding of the processes that determine the variability of heat transport in the Atlantic Ocean, and its effects on the atmosphere. Whereas the total ocean heat transport is poleward in both hemispheres, the heat transport in the Atlantic is northward even in the Southern Hemisphere (e.g., Peixoto and Oort, 1993) This surprising situation is a consequence of the thermohaline circulation, in which deep water formation in the North Atlantic plays a key role. Hadley Centre climate model HadCM3 is reported This model requires no flux corrections to maintain a stable climate and is an excellent tool for studying heat transports and their variability.
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call