Scientists will gain new insights about water on Earth like never before. Thanks to these multibillion-dollar satellites, from the whirlpools that help shape global climate, to millions of lakes and rivers can be detected.
The USD 1.2 billion Surface Water and Ocean Topography (SWOT) satellite will be launched on December 15 from Vandenberg Space Force Base in California, United States. This satellite promises to deepen research into the global water cycle, and will reveal new knowledge about our warming Earth.
Through a joint mission led by NASA and the French National Center for Space Studies, SWOT will reflect radar from the surface of water on Earth. The satellites will allow scientists to measure and track the height, area and movement of water across the planet in incredible detail.
"This is a breakthrough," said Rosemary Morrow, an oceanographer at the Laboratory of Space, Geophysical and Oceanographic Studies in Toulouse, France and one of the leaders of the mission, quoted from Nature.
Lakes and rivers
"Based on publicly available data, there are 10,000-20,000 of the roughly 6 million larger lakes and reservoirs on Earth on the planet today," said Tamlin Pavelsky, a hydrologist at the University of North Carolina at Chapel Hill.
The SWOT mission will measure nearly all of those 6 million lakes and reservoirs every 10 or 11 days. "We've never made measurements like this before," says Pavelsky.
In 2021, a team led by Sarah Cooley, a geographer at Oregon State University in Eugene collected existing satellite measurements of surface area and water level for about 227,000 lakes, but Cooley says those measurements are only available every 90 days.
"The data that SWOT will provide will be much larger than what we can do," Cooley said.
SWOT helps advance river hydrology technology. In anticipation of the satellite's launch, researchers are developing new ways to modify the measurement of water level, range, and elevation changes.
By applying the technique to existing satellite data, scientists estimate that rivers brought up to 17% more fresh water to the Arctic Ocean between 1984 and 2018 than previously thought. It is hoped that the presence of SWOT will refine these forecasts while enabling similar work across the Earth.
"SWOT will change the face of hydrology," said Colin Gleason, a geographer at the University of Massachusetts Amherst.
Ocean vortex
Similar advances in hydrology are also expected in the ocean. SWOT is expected to provide high-resolution measurements that will allow scientists to track ocean currents, eddies, and tidal flows.
This function will support the understanding of water circulation and enhance high-resolution models that can track the transfer of heat and carbon dioxide from a warming atmosphere to the depths of the oceans.
An international consortium involving the United States, France, Australia and others is planning field expeditions in 18 oceanic locations around the world next year. This will help calibrate the SWOT data against measurements in deep places, in a variety of ocean conditions.