1. a British Antarctic Survey, Cambridge, United Kingdom
2. b NORCE Norwegian Research Centre, Bjerknes Centre for Climate Research, Bergen, Norway
3. c Norwegian Meteorological Institute, Oslo, Norway
4. d Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research–Research Unit, Potsdam, Germany
5. e Finnish Meteorological Institute, Helsinki, Finland
6. f Institute for Marine and Atmospheric Research, Utrecht University, Utrecht, Netherlands