Correcting for artificial heat in sea ice perturbation experiments

A common approach to assessing how polar amplification affects lower latitude climate is to perform coupled ocean-atmosphere experiments in which sea ice is perturbed to a future state. Recent work by M. England and others uses a simple 1-dimensional energy balance model (EBM) to show that sea ice perturbation experiments add an artificial heat flux to the climate system. In this presentation, I will confirm this effect in a broader range of models and suggest a technique to correct for the artificial heat post-hoc. The technique successfully corrects for artificial heat in the EBM, and a possible generalization of this approach is developed to correct for artificial heat in an albedo modification experiment in a comprehensive earth system model. Generalizing this technique to sea ice perturbation methodologies that employ a "ghost flux" seen only by the sea ice model would require a better understanding of the effect of ghost fluxes on the surface energy budget. Applying the correction to the comprehensive albedo modification experiment, we find stronger artificial warming than in the EBM. Failing to account for the artificial heat also leads to overestimation of the climate response to sea ice loss, and can suggest false or artificially strong "tugs-of-war" between low latitude warming and sea ice loss over some fields, for example Arctic surface temperature and zonal wind.