Extratropical control of tropical climate, the atmospheric bridge and oceanic tunnel

[1] A coupled ocean-atmosphere model study shows that the extratropical impact on tropical climate is as strong as the tropical impact on extratropical climate. A 2degreesC SST warming in the global extratropics increases equatorial ocean temperature by similar to1degreesC in the surface and subsurface. The surface temperature change is caused by the atmospheric bridge of the Hadley circulation (70%) and the oceanic tunnel of thermocline subduction (30%), while the subsurface temperature change is forced predominantly through the oceanic tunnel. Furthermore, the dominant influence on the equator comes from the southern hemisphere atmosphere and ocean.