The variations are generally measured in centimeters, but can be up to a few meters. These changes might seem insignificant, until you think about the fact that when the sea level changes by a few centimeters, the tilt of the surface can result in an ocean current carrying several millions of cubic meters of water per second. From data about sea surface height, scientists are learning about ocean currents, climate, seasonal changes, winds, waves and weather, global sea level change, eddy detection and El Niqo events. This information has also turned out to be unexpectedly useful for marine mammal surveys and shipping operations. Of particular interest are eddies, swirls of water currents that spin off from a large current or are forced by wind, that are comparable to atmospheric storms.
Eddies play an important role in transporting heat, salt and nutrients around the globe.
Ocean eddies can last for weeks or months, can have diameters of tens to hundreds of kilometers, and can extend deep into the sea. Rapidly swirling eddies cause the greatest changes in sea height. Satellite tracking of eddies has proven useful in studies of the distribution and abundance of whales. Correlations between eddy locations and the migration routes of sperm whales have been found. Information from the satellite is used to generate near real-time maps, which can direct marine biologists to areas where whales are likely to be found.