Senior Science Reporter on New Ocean Mapping Technology

is a senior science reporter covering energy and the environment with more than a decade of experience. She is also the host of Hell or High Water: When Disaster Hits Home , a podcast from Vox Media and Audible Originals.

New Satellite Technology Reveals Detailed Seafloor Map

The world has a more detailed map of the seafloor than ever before thanks to observations taken from space. NASA published a video this week showing a remarkably clear picture of the bottom of the ocean made possible thanks to new satellite technology.

The face of the moon has been more thoroughly mapped than the depths of Earth’s oceans. But after NASA and French space agency CNES launched the Surface Water and Ocean Topography (SWOT) satellite in 2022, we’re starting to get a clearer look at what lies in the deep. In December, researchers published a revelatory seafloor map in the journal Science using one year of SWOT data.

The satellite helps fill in vast gaps in data collected by ship, and offers a higher resolution picture than previous satellites have been able to provide. On a practical level, the maps can help submarines navigate more safely through previously mysterious ocean terrains. They can also inform the precarious work of laying down and repairing underwater telecommunication cables that keep people connected across our planet.

NASA’s new video is also just fun to watch. The animation shows what the seafloor looks like off the coasts of Mexico, South America, and the Antarctic Peninsula. Research using data from SWOT is ongoing, so we can expect more insights into the ocean’s abyss in the future.

How SWOT Works

The maps use gravity-based data to reveal features researchers had never seen before. Because of their larger mass, rolling abyssal hills and undersea volcanoes called seamounts exert stronger gravitational pull than their surroundings. SWOT can note those subtle differences by observing bumps above along the surface of the sea. In the video, regions colored green are higher relative to purple-colored regions.

This method allows SWOT to detect abyssal hills and other features that were too small for older satellites to find using radar pulses. “We were surprised that SWOT could see them so well,” Yao Yu, an oceanographer at Scripps Institution of Oceanography and lead author of the Science paper, said in a NASA blog published this week. Researchers now know that those hills, formed where tectonic plates pull apart from each other, blanket about 70 percent of the ocean floor. That makes them the most common landform on Earth, according to Yu.

Ships using sonar can also map abyssal hills, but it’s a slow and difficult task. To date, ships have only mapped about a quarter of the planet’s ocean floor.

SWOT was designed to do much more than map the seafloor. Its main purpose is to measure the height of water over oceans, rivers, lakes, and other bodies of water, a mission to take the first complete survey of Earth’s surface water.