To gather long-term information about the world's oceans and currents, orbiting instruments must take extremely precise measurements of the height of the ocean surface - commonly called sea level - above the center of the Earth. This is referred to as ocean surface topography; not to be confused with bathymetry, which is the topographic relief on the bottom of the ocean. Ocean surface topography data contains information that has significant practical applications in such areas as the study of worldwide weather and climate patterns, the monitoring of shoreline evolution, and the protection of our great ocean fisheries. There are many scientists studying this information. The image at right shows the latest satellite ocean surface topography data.
Ocean topography missions like Jason-1 and OSTM/Jason-2 seek to satisfy the following science goals: