Do Thermodynamics Constrain How the Arctic Atmospheric Heat Engine Can Change in a Warming Climate?

The atmospheric heat engine is driven by the coupling between incoming and outgoing solar radiation and the exchange of heat through the atmosphere's boundary layer. This heat engine generates weather patterns which redistribute heat and moisture around the globe and is particularly important for the polar regions. In the Arctic, it is the balance between atmospheric heat transport and radiative cooling that give rise to the atmospheric heat engine. In this presentation, reanalysis data are used to discuss the mean thermodynamic paths of air masses transiting through the Arctic and explain their relationship with the global atmospheric circulation. It is shown that this last relationship determines the inter annual variability of the Arctic temperature profile and that, as a consequence, a changing global atmospheric circulation might constrain how the Arctic atmosphere might warm with anthropogenic forcing. Comparison with a subset of simulations of the twenty-first century from the Coupled Model Intercomparison Project phase 5 (CMIP5) confirm this behavior.