Geopotential Difference : The work per unit mass gained or required in moving a unit mass vertically from one geopotential surface to another. See: Geopotential, Geopotential Anomaly, And Geopotential Topography
National Oceanic and Atmospheric Administration NOAA, Tide and Current Glossary, National Ocean Service, CO-OPS, Products and Services N/OPS3, Silver Spring, MD, USA 1999. http://co-ops.nos.noaa.gov/publications/glossary2. pdf, (ND/ Tide and Current - Amer) {830}