Vertical Redistribution of Oceanic Heat Content

Abstract:

Estimated values of recent oceanic heat uptake are of order of a few tenths of a watt/m², and are a very small residual of air-sea exchanges with annual average regional magnitudes of hundreds of watts/m². By using a dynamically consistent state estimate, the redistribution of heat within the ocean is calculated over a 20-year period. The results support an inference that the near-surface thermal properties of the ocean are a consequence, at least in part, of internal redistributions of heat, some of which must reflect water that has undergone long trajectories since last exposure to the atmosphere. The small residual heat exchange with the atmosphere today is unlikely to represent the interaction with an ocean that was in thermal equilibrium at the start of global warming. An analogy is drawn with carbon-14 "reservoir ages" which range over hundreds to a thousand years.