Tides
4
H|0|dataflo|corrected|1043|1051|
G|0|geodetic|geodetic|569|576|
G|0|2cm|2 centimeters|482|494|
G|0|accuracy|accuracy|470|477|
    Tides are the natural rise and fall of sea level due to pulls of gravity between the Sun, earth and Moon. The orbit of TOPEX/Poseidon was especially chosen to permit the satellite to measure the solar and lunar tides. 
    A significant accomplishment of TOPEX/Poseidon is that data from the satellite have been used by the Science Team to produce the most accurate global maps of tides. As a result, tides can now be predicted everywhere in the deep ocean with an accuracy of 2 centimeters. 
    This level of accuracy is necessary to understand many oceanic and geodetic processes: tides are important for navigation especially in coastal regions; tides slow up the rotation of the moon around the earth, and cause the moon to keep the same face toward the earth; the weight of the tides depresses the sea floor, disrupting measurements of gravity on land; and finally, tides change the orbits of artificial satellites, such as the Hubble Space Telescope and TOPEX/Poseidon. 
    Once TOPEX/Poseidon measurements of sea level have been corrected for the influences of tides, the data are used for the study of ocean circulation. 
