Meridional heat transport by the subtropical cell

The wind-driven circulation adds a significant contribution to poleward mer idional heat transport. Numerical models indicate that equatorward of phi(0 ), the zero wind stress latitude (30 degrees lat), most of the wind-induced heat transport is due to the meridional overturning circulation known as t he subtropical cell. The volume transport of this overturning is approximat ely given by the surface Ekman transport. By combining this fact with the a ssumption that Ekman-downwelled water approximately follows isotherms excep t near the equator, the authors derive an expression for the meridional hea t transport that depends only on wind stress and surface temperature. The e xpression is confirmed in numerical models with simplified geometry and for cing. Numerical results indicate that peak heat transport due to the subtro pical cell is about 0.1 x 10(15) W for the North Atlantic and 0.3 x 10(15) W for the North Pacific.