Nicole S Lovenduski, University of Colorado, Department of Atmospheric and Oceanic Sciences, Boulder, CO, United States, Stephen G Yeager, NCAR, Oceanography, Boulder, CO, United States, Riley Xavier Brady, University of Colorado at Boulder, Department of Atmospheric and Oceanic Sciences, Boulder, CO, United States and Kristen M. Krumhardt, National Center for Atmospheric Research, Boulder, CO, United States