Amazing stuff! However, an 8-kilometer spatial resolution is not too impressive.
"... researchers using data from a cutting-edge satellite released a new map of the global seafloor charting more than 200,000 of these [abyssal] hills. Launched two years ago by NASA and CNES, France’s national space agency, the Surface Water and Ocean Topography (SWOT) satellite is primarily meant to map the height of ocean swirls and rivers in fine detail. But by looking at subtle ways water piles about these large seafloor features due to gravity, it can also map the abyss.
After just one year, seafloor maps created by SWOT have already outpaced those assembled from decades of older technology. With only 25% of the ocean bottom mapped by sonar, the SWOT maps will fill critical gaps for decades to come. And in particular, its view of the abyssal hills—one of the fundamental fabrics of Earth’s surface—will allow plate tectonics to be studied in fine detail, perhaps triggering a new boom in the field. ..."
From the perspective abstract:
"Global marine gravity fields—variations in Earth’s gravitational pull across the ocean surface—provide valuable information about seafloor topography and plate tectonics beneath the water, knowledge that is essential for understanding geological features and ocean dynamics.
A technique that estimates Earth’s surface heights from space, called satellite altimetry, has partially resolved marine gravity fields. However, conventional altimetry can only obtain one-dimensional measurements along a satellite track. The 2022 Surface Water and Ocean Topography (SWOT) mission marked a considerable advancement in satellite altimetry because it captures two-dimensional, large-area topography data with high precision (3). On page 1251 of this issue, Yu et al. (4) report that a gravity field derived from 1 year of SWOT data reveals plate tectonics along the deep ocean floor that had remained hidden for the past 30 years with conventional altimeter observations. This level of detail could improve understanding of ocean environment and dynamics."
From the editor's summary and abstract:
"Editor’s summary
Detailed maps of the ocean floor come from ship crossings but can also be obtained using satellite altimetry. Yu et al. used radar altimetry observations from just 1 year of the Surface Water and Ocean Topography mission to develop a high-resolution global seafloor map ... The new satellite observations have a resolution about twice that of the older observations, presenting an opportunity to better understand the geological features of the seafloor. ...
Abstract
The global ocean covers 71% of Earth’s surface, yet the seafloor is poorly charted compared with land, the Moon, Mars, and Venus. Traditional ocean mapping uses ship-based soundings and nadir satellite radar altimetry—one limited in spatial coverage and the other in spatial resolution. The joint NASA–CNES (Centre National d’Etudes Spatiales) Surface Water and Ocean Topography (SWOT) mission uses phase-coherent, wide-swath radar altimetry to measure ocean surface heights at high precision. We show that 1 year of SWOT data offers more detailed information than 30 years of satellite nadir altimetry in marine gravity, enabling the detection of intricate seafloor structures at 8-kilometer spatial resolution. With the mission still ongoing, SWOT promises critical insights for bathymetric charting, tectonic plate reconstruction, underwater navigation, and deep ocean mixing."
Transforming coastal mapping from space (no public access)
Abyssal marine tectonics from the SWOT mission (no public access)
The parallel ridges of abyssal hills, as seen by the Surface Water and Ocean Topography satellite, extend out from the flanks of a seafloor spreading center (black lines) in the Indian Ocean.
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