SWOT: A space mission to map the surface of Earth’s water bodies: a baseline for a world-wide oceanographic survey

Scientists are going to get an unbelievable view of Earth’s water, from swirling ocean eddies that help shape the global climate to millions of lakes and rivers.

A mission led by NASA and the French National Centre for Space Studies is going to bounce radar off of the surface of Earth’s water bodies, which is too small to be tracked from space. The satellite will enable scientists to measure and track the elevation, extent and movement of water across the planet in ground-breaking detail.

Rosemary Morrow is an oceanographer at the laboratory of space, gyrology and oceanographic studies in Toulouse, France, one of the scientists leading the mission. “It will be like putting on a pair of glasses when you are short-sighted: things are sort of vague, and then suddenly everything comes into clarity.”

The current public data for over five million lakes and bigger is only available for about one hour a year, says a hydrologist at the University of North Carolina at Chapel Hill. SWOT will measure nearly all 6 million every 10 or 11 days. It was the first time we had measurements like this. We do not have a baseline.

Colin Gleason, a geographer at the University of Massachusetts Amherst and an author on both studies says that if SWOT does what we think it will do, it’s going to change the face of hydrology.

An international consortium involving the United States, France, Australia and others is planning field expeditions at 18 ocean sites around the world next year. These will allow us to calibrate the data against on-site measurements.

Billions of people live in fast-changing coastal areas and must develop plans to adapt to a future with rising seas, crumbing cliffs, and devastating hurricanes. They will get help from a dedicated satellite.

In 2000, NASA flew radar antennas on the space shuttle Endeavour to map the topography of land, but that was only an 11-day mission. SWOT’s KaRIn will considerably improve on the concept. “This instrument will be able to measure the height of water with centimeter accuracy. From a distance of 900 kilometers away from the surface, it is kind of incredible that we can improve accuracy by a factor of 100.