Séminaire
Arctic amplification, broadly defined as greater-than-global Arctic warming in response to external forcing and/or internal climate variability, is ubiquitous in climate models and observations. Despite a long and rich history of numerical model experiments and observational analysis, the relative importance of the processes controlling Arctic amplification is still subject to debate. In this talk, I use coupled climate model experiments to identify the influence of atmospheric processes and ocean model complexity (slab ocean vs. full-depth ocean) on the equilibrium Arctic climate response to an instantaneous carbon dioxide
doubling. My findings underscore that local shortwave feedbacks (positive surface albedo, negative cloud) can be more important than northward heat transport for explaining the equilibrium Arctic surface climate response and response differences in coupled climate models. That said, the processes explaining the equilibrium climate response differences I describe are different than the processes explaining inter-model spread in transient climate projections.
MP Lefebvre (01 44 27 27 99)