Venice flood

This type of forecasting has enormous societal and economical consequences. For example, it allows scientists to forecast El Niño events and the flooding of low-lying areas (such as Venice), as well as predict the trajectory of pollutants, which allows oil spills to be contained more quickly by placing barriers in their pathways.

The ability to measure the sea surface height, which varies across the ocean, with such accuracy allowed oceanographers to discover planetary waves, which Paolo Cipollini, of the National Oceanography Centre in the UK, names as the real success story of radar altimetry.

Planetary waves, also called Rossby waves, were theorised to have existed in the ocean as far back as 1930, but it was impossible to know for sure because they occur internally and are very small on the surface, about 10 centimetres high, making them impossible to detect from onboard an oceanographic research vessel.

According to Cipollini, radar altimetry offered proof of these waves for the first time. As oceanographers started mapping the sea surface height, they began seeing the internal waves, which extend 500 or 1000 kilometres underneath the ocean, moving by following the measurements on the surface.