1. Department of Earth Sciences, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
2. School of Oceanography, University of Washington, 1503 NE Boat Street, Seattle, WA 98105, USA
3. Department of Earth Sciences, University of Southern California, Los Angeles, CA 90089, USA
4. Department of Earth Sciences, ETH Zürich, Clausiusstrasse 25, 8092 Zürich, Switzerland
5. College of Marine Science, University of South Florida, St Petersburg, FL 33701, USA
6. Laboratoire des Sciences du Climat et de l'Environnement (LSCE), IPSL, CEA–Orme des Merisiers, 91191 Gif-sur-Yvette, France
7. Laboratoire d'Etudes en Géophysique et Océanographie Spatiales (LEGOS), 14 Avenue Edouard Belin, 31400 Toulouse, France
8. Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901, USA
9. School of Environmental Sciences, University of Liverpool, Jane Herdman Building, Liverpool L69 3GP, UK