Speaker: Shineng Hu (Duke Univ.)
Topic: Global warming pattern formation: the role of ocean heat uptake

Under global warming, strong ocean heat uptake occurs over the subpolar North Atlantic and the Southern Ocean, due mainly to changing ocean circulation. Here we use a slab ocean-atmosphere coupled model to demonstrate that ocean heat uptake plays an important role in shaping the surface warming pattern in response to a doubling CO2. We find that the extratropics-centered ocean heat uptake pattern acts to mute the polar amplification of CO2-induced warming in both hemispheres, especially over Antarctica, and also contributes significantly to the equatorially enhanced warming pattern in all three ocean basins. The spatially varying component of ocean heat uptake, although globally averaged to zero, can effectively rectify and lead to decreased global mean surface temperature of a comparable magnitude as the effect of global mean ocean heat uptake under transient climate change. Our study highlights that the problem of surface warming pattern formation needs to be placed in an ocean-atmosphere coupled context and that the ocean heat uptake pattern is a key.