Given the uncertainty in all processes involved in polar amplification, elucidating the role of energy and moisture transport is crucial. To assess the role of heat transport by the atmosphere and the ocean, we use the simulations from the Polar Amplification Model Intercomparison Project (PAMIP) to separate the effects of sea ice loss and sea surface warming. We also complement the PAMIP coupled sea ice loss experiments with a CO2 doubling experiment in a fixed sea ice state with both a full ocean model and a thermodynamic ocean (slab ocean model) coupled to WACCM4. The sea ice in each coupled experiments in constrained by a novel hybrid nudging method combining both longwave forcing and direct sea ice area nudging.

We describe heat transport between the tropics and the high latitudes using a moist isentropic circulation framework that accounts for moisture and eddy transport. Through this framework, we separate the contribution of the midlatitude eddies intensity from the contribution of the sensible and latent heating to poleward heat transport. We compare the effect of fixed sea surface temperature, slab ocean coupling and full ocean coupling on the atmospheric heat transport changes induced by sea ice loss and CO2 doubling.