From orbit 1,330 kilometers above Earth, TOPEX/Poseidon provided measurements of the surface height of 95 percent of the ice-free ocean to an accuracy of 3.3 centimeters.

The satellite's measurements of the hills and valleys of the sea surface led to a fundamentally new understanding of ocean circulation and its effect on climate.

TOPEX/Poseidon made it possible for the first time to compare computer models of ocean circulation with actual global observations and use the data to improve climate predictions.

[3] Some of the areas in which the data are used include:[7] TOPEX/Poseidon's follow-on mission, Jason-1,[8] was launched in 2001 to continue the ongoing measurements of sea surface topography.

In addition to the altimeters, the TOPEX Microwave Radiometer (TMR) operating at 18, 21, and 37 GHz was used to correct for atmospheric wet path delay.

Precise orbit determination is crucial because errors in locating the spacecraft would distort the sea level measurement calculated from the altimeter readings.

Knowing the satellite's precise position to within 2 centimeters (less than 1 inch) in altitude was a key component in making accurate ocean height measurements possible.