Antara Banerjee, Cooperative Institute for Research in Environmental Sciences, Boulder, CO, United States; National Oceanic and Atmospheric Administration / Earth System Research Laboratory, Chemical Sciences Division, Boulder, CO, United States, John C Fyfe, Environment Canada, Canadian Centre for Climate Modeling and Analysis, Victoria, BC, Canada, Lorenzo M Polvani, Columbia University, Department of Applied Physics and Applied Mathematics, New York, NY, United States and Darryn Waugh, Johns Hopkins Univ, Baltimore, MD, United States