Gabriela Negrete Garcia, Scripps Institution of Oceanography, La Jolla, CA, United States, Nicole S Lovenduski, University of Colorado, Department of Atmospheric and Oceanic Sciences, Boulder, CO, United States, Claudine Hauri, University of Alaska Fairbanks, International Arctic Research Center, Fairbanks, AK, United States, Kristen M. Krumhardt, National Center for Atmospheric Research, Boulder, CO, United States and Siv K Lauvset, NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway