Increasing fall-winter energy loss from the Arctic Ocean and its role in Arctic temperature amplification

Arctic surface temperatures have risen faster than the global average in recent decades, in part due to positive feedbacks associated with the rapidly diminishing sea ice cover. Counter-intuitively, the Arctic warming has been strongest in late fall and early winter whilst sea ice reductions and the direct ice-albedo feedback have been greatest in summer and early fall. To reconcile this, previous studies have hypothesized that fall/winter Arctic warming has been enhanced by increased oceanic heat loss but have not presented quantitative evidence. Here we show increases in heat transfer from the Arctic Ocean to the overlying atmosphere during October–January, 1989–2009. The trends in surface air temperature, sea ice concentration and the surface heat fluxes display remarkable spatial correspondence. The increased oceanic heat loss is likely a combination of the direct response to fall/winter sea ice loss, and the indirect response to summer sea ice loss and increased summer ocean heating.