Compensation in the heat balance of outcroppping isotherms

The traditional view of the oceanic heat budget is that water is warmed at the surface in low latitudes, where sea surface temperatures are high, and cooled at the surface in high latitudes, where sea surface temperatures are low. In this work, by analyzing observed net surface heat flux as a function of temperature class, we challenge that traditional view and show that all sea surface temperature classes experience both cooling and warming.

Further analysis indicates that two temperature classes, [20C-25C] and [0C-10C], display an interesting tendency for compensation: for these, the net sum of the cooling and warming they experience cancels approximately. This result is suggested to reflect the `pseudo-adiabatic' character of:

(i) the shallow ventilated thermocline, connecting tropics and midlatitudes ([20C-25C] class).

(ii) the deep overturning circulation of the global ocean, connecting Southern and Northern hemispheres ([0C-10C] class).

The timescales over which these compensations are established will be discussed.