Using satellite altimetry data from SWOT, scientists created a global map of ocean gravity and discovered thousands of new seamounts. (Etvös is a unit that measures the ocean’s vertical gravity gradient.) Credit: Yao Yu et al, Science (2024). DOI: 10.1126/science.ads4472
The Surface Water Ocean Topography (SWOT) mission instrument has enabled the clearest satellite-generated ocean floor map to date, according to new research published in the journal Science. The study could help researchers better understand everything from biodiversity hotspots to plate tectonics to tsunami propagation.
Ship-based sonar has a resolution of approximately 200 to 400 meters (650 to 1,300 feet). The Seabed 2030 project aims to use this technique to map the entire ocean floor by the end of the decade. But the relatively slow and expensive technology has so far only imaged about 25% of the ocean floor.
Most seafloor map images come from satellite altimeters, which measure changes in sea surface height. Scientists use this information to make inferences about features of the ocean floor that affect ocean gravity and thus affect sea level (for example, sea level is higher than seamounts). Over the past 30 years, data collected by satellite instruments has allowed scientists to map ocean gravity at a resolution of about 12 to 16 kilometers (7.5 to 9.9 miles).
SWOT, jointly developed by NASA and the Center National de la Space d’Etudes (CNES, France’s national space agency) and launched in 2022, measures sea surface height in two dimensions instead of one. In the new study, researchers used SWOT data from April 2023 to July 2024 to map ocean gravity at 8 kilometers (5 miles) resolution.
“In other words, one year of SWOT data exceeded the previous 30 years of conventional nadir altimeter (data) in building ocean gravity,” said the study’s lead author, a professor of ocean geophysics at the Scripps Institution. said Yao Yu, a postdoctoral researcher who studies science and physical oceanography. in oceanography from the University of California, San Diego.
The increased resolution has led to the discovery of thousands of small seamounts, allowing researchers to better characterize deep-sea hills and map underwater canyons. Detecting these features could improve studies of ocean circulation and deep-sea mixing, which can affect ocean temperatures and carbon dioxide uptake.
“We are impressed by the ability to (map) deep-sea hills and seamounts more (clearly) than ever before,” Ole Balthasar Andersen, a geophysicist at the Technical University of Denmark, wrote in an email. Andersen was not involved in the study, but he collaborated with David Sandwell, Yu’s advisor and co-author of the paper. “This paper represents a major advance in our ability to map the Earth.”
Nadia Vinogradova Schiffer, a NASA oceanography physicist and SWOT program scientist, wrote in an email that the study was “impressive” and brought a new level of detail to satellite altimetry capabilities. .
“Improving seafloor mapping at this level of detail opens new frontiers in fields such as geodesy, ocean modeling, hydrology, navigation and benthic ecology,” he said.
Further information: Yao Yu et al., Deep Ocean Tectonics from the SWOT Mission, Science (2024). DOI: 10.1126/science.ads4472
This article is republished courtesy of Eos, sponsored by the American Geophysical Union. Read the original story here.
Citation: Satellite measurements greatly improve ocean floor mapping (December 13, 2024) Retrieved December 15, 2024 from https://phys.org/news/2024-12-satellite-major-seafloor.html
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