Item

Abstract

Longwave radiation and turbulent heat uxes are the mechanisms by which the Earth's surface transfers heat into the atmosphere, thus aecting the surface temperature. However, the energy partitioning between the radiative and turbulent components is poorly constrained by energy and mass balances alone. We use a simple energy balance model with the thermodynamic limit of maximum power as an additional constraint to determine this partitioning. Despite discrepancies over tropical oceans, we nd that the broad variation of heat uxes and surface temperatures in the ERA-Interim reanalysed observations can be recovered from this approach. The estimates depend considerably on the formulation of longwave radiative transfer and a spatially uniform oset is related to the assumed cold temperature sink at which the heat engine operates. Our results suggest that the steady state surface energy partitioning may reect the maximum power constraint Turbulent heat uxes are treated as the result of a heat engine operating between the surface and the atmosphere. Turbulent heat uxes are determined by maximizing the mechanical power output as an additional thermodynamic constraint. Despite discrepancies over tropical ocean, broad patterns of turbulent fluxes and temperatures of ERA-Interim can be recovered.