An international effort to measure sea levels is set to launch a satellite to measure the height of the ocean. The Sentinel-6 Michael Freilich satellite is scheduled to head into orbit on a SpaceX Falcon 9 rocket. (Nov. 20)
JOSH WILLIS: This thing has a radar that tells us how far the satellite is from the ocean surface. So it bounces a wave off, measures the return time. And then it also has a bunch of positioning systems. So if you know where the satellite is, if you know how far it is from the water, then you can use both of those pieces of information to tell you how tall the ocean is.
Traditionally, we measure sea level at the coastline with tide gauges. And these are great records. Some of them go back more than 100 years. So they give us a historical perspective.
But they're only at those single points. And the oceans cover more than 2/3 of the planet's surface. So if you want to see the whole thing, you have to do it from the bird's eye view.