height_above_reference_ellipsoid

"Height_above_X" means the vertical distance above the named surface X. A reference ellipsoid is a mathematical figure that approximates the geoid. The geoid is a surface of constant geopotential with which mean sea level would coincide if the ocean were at rest. The ellipsoid is an approximation because the geoid is an irregular shape. A number of reference ellipsoids are defined for use in the field of geodesy. To specify which reference ellipsoid is being used, a grid_mapping variable should be attached to the data variable as described in Chapter 5.6 of the CF Convention. rdf:langString