1. a Scripps Institution of Oceanography , La Jolla, California, USA
2. b NOAA , Silver Spring, Maryland, USA
3. c U.S. Naval Oceanographic Office , Stennis Space Center, Mississippi, USA
4. d National Geospatial-Intelligence Agency , St. Louis, Missouri, and Bethesda, Maryland, USA
5. e International Hydrographic Bureau , Monaco
6. f British Oceanographic Data Centre , Liverpool, UK