 scale, the satellite has been able to watch the daily tides around the world, and a small El Nino-type event when a mound of water 10cm high and several thousand kilometres across moved eastwards across the Pacific over a period of several months.
In decades to come, such satellites will be able to reveal actual changes in sea level caused by climate change, while providing the data significantly to improve computer models of ocean behaviour Although Topex-Poseidon's active life is unlikely to exceed five years, other satellites are already on the way, starting with the launch of ERS-2 at the end of this year. They will play a major role in the setting up of a Global Ocean Observing System by the end of the century.