Ocean surface topography or sea surface topography, also called ocean dynamic topography, are highs and lows on the ocean surface, similar to the hills and valleys of Earth's land surface depicted on a topographic map.
These variations are expressed in terms of average sea surface height (SSH) relative to Earth's geoid.[1] The main purpose of measuring ocean surface topography is to understand the large-scale ocean circulation.
^[In most absolute form, it may be expressed in terms of a geocentric radius.]