Session: Warm Climates (Mid-Holocene, Last interglacial, Deep-time, Pliocene)
Author: Jianqiu Zheng / email@example.com / University of science and technology of China; Stockholm University
Co-author: Qiong Zhang, Stockholm University;
Qiang Li, Stockholm University;
Qiang Zhang, Stockholm University;
Arctic amplification is becoming one of the most highlighted issues while the record of global warming and Arctic sea-ice extent minimum have been refreshed frequently over the last decade. As a potential analogue of future climate projection, the Arctic amplification in mid-Pliocene is of special interest as its magnitude is significantly greater than that of present, though the carbon dioxide concentration is comparable during the two periods. Strong Arctic amplification that comparable with PRISM reconstructions is identified in a mid-Pliocene simulation with EC-Earth. A quantification of process contribution using the Climate Feedback and Response Analysis Method (CFRAM) shows that the largest contributor to Arctic amplification is sea-ice albedo feedback and cloud feedback plays a secondary role, whereas the latent and sensible heat fluxes largely offset Arctic amplification through a negative feedback. Significant sea-ice melting is found during summer months from June to October. The large area of open-water facilitates oceanic dynamical process to store large amount of heat content in the ocean. The stored energy is discharged in winter to sea surface, heats the overlying atmosphere through turbulent heat fluxes, and thus maintains the more pronounced Arctic amplification in winter in spite of no incoming solar radiation during polar night.