Meridional Heat Transport

Meridional heat transport is the net poleward movement of heat by the ocean and atmosphere across a latitude circle, the balance term that keeps the tropics from overheating and the poles from freezing. The combined transport peaks near 5 to 6 PW around 35 degrees latitude in each hemisphere; the ocean carries the larger share in the tropics, the atmosphere at higher latitudes. The ocean component is dominated by the meridional overturning circulation and by wind-driven gyres, with the Atlantic uniquely exporting heat northward across the equator. It is estimated from hydrographic sections, the RAPID 26 degrees N array, and reanalyses.