Dec. 13 () –
Instruments on board the satellite SWOT (Surface Water and Ocean Topography) have made it possible to obtain the clearest global-scale seafloor map produced to date from orbit.
The work could help researchers better understand everything from biodiversity hotspots to plate tectonics and tsunami propagation, according to Eosa journal of the American Geophysical Union (AGU). The findings are published in Science.
A sonar installed on a ship has a resolution of about 200 to 400 meters. The Seabed 2030 project aims to map the entire seabed by the end of the decade using this method. However, this time-consuming and expensive technique has so far only imaged about 25% of the seafloor.
Most seafloor map images are derived from satellite altimetry, which measures variations in height of the ocean surface. Scientists use this information to make inferences about seafloor features that influence sea surface level by affecting marine gravity (for example, sea level is higher on a seamount). Over the past 30 years, data collected by satellite instruments has allowed scientists to map marine gravity with a resolution of between 12 and 16 kilometers.
Jointly developed by NASA and the National Center for Space Studies (CNES, the French national space agency) and launched in 2022, SWOT measures the height of the sea surface in two dimensions instead of one. In the new study, researchers used SWOT data from April 2023 to July 2024 to map marine gravity with a resolution of 8 kilometers (5 miles).
“Therefore, one year of SWOT data surpassed the last 30 years of traditional nadir altimeter [datos] in marine gravity construction“said Yao Yu, lead author of the study and a postdoctoral researcher who studies marine geophysics and physical oceanography at the Scripps Institution of Oceanography at the University of California, San Diego.
THOUSANDS OF NEW SMALL SEAMOUNTS
Improved resolution has revealed thousands of small seamounts and is allowing researchers to better characterize abyssal hills and map underwater canyons. Detecting these features could help improve studies of ocean circulation and mixing in the deep ocean, which can affect ocean temperatures and carbon dioxide uptake.
“I am impressed with the ability to (map) abyssal hills and seamounts much (more clearly) than ever before” wrote Ole Baltazar Andersen, a geophysicist at the Technical University of Denmark, in an email.
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