1. a Scripps Institution of Oceanography, University of California, San Diego, La Jolla, California
2. b Woods Hole Oceanographic Institution, Woods Hole, Massachusetts
3. c Geophysical Institute, University of Bergen, Bergen, Norway
4. d Bjerknes Center for Climate Research, Bergen, Norway
5. e Georgia Institute of Technology, Atlanta, Georgia
6. f National Oceanography Centre, Southampton, United Kingdom