Global view of seafloor gravity and bathymetry from one year of Swot

Vertical gravity gradient in the Pacific, west of the Peruvian coast (refer to the bottom global map for the specific location). It shows the presence of seamounts, indicated by red "dots". While larger seamounts have been cataloged, those less than 1-km tall (such as the two seamounts around 96.5°W, 5°S indicated by the red arrows) were mostly uncharted. These smaller seamounts can be clearly observed using Swot's capabilities. This will significantly enhance the global seamount catalog, from the currently recorded 44.000 up to possibly 100.000. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)
Vertical gravity gradient in the Pacific, west of the Peruvian coast (refer to the bottom global map for the specific location). It shows the presence of seamounts, indicated by red "dots". While larger seamounts have been cataloged, those less than 1-km tall (such as the two seamounts around 96.5°W, 5°S indicated by the red arrows) were mostly uncharted. These smaller seamounts can be clearly observed using Swot's capabilities. This will significantly enhance the global seamount catalog, from the currently recorded 44.000 up to possibly 100.000. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)
Abyssal are the most common landform on Earth. Abyssal hills, shown in this vertical gravity gradient map in the South Indian Ocean as parallel lines (such as the ones highlighted in green in the yellow box), form at seafloor spreading ridges (black thick lines) and thus reveal past plate tectonics. Prior to Swot, abyssal hills were only mapped from dedicated ships using multibeam sonar. Within the processed Swot data they are visible almost everywhere in the ocean basins. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)
Abyssal are the most common landform on Earth. Abyssal hills, shown in this vertical gravity gradient map in the South Indian Ocean as parallel lines (such as the ones highlighted in green in the yellow box), form at seafloor spreading ridges (black thick lines) and thus reveal past plate tectonics. Prior to Swot, abyssal hills were only mapped from dedicated ships using multibeam sonar. Within the processed Swot data they are visible almost everywhere in the ocean basins. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)
The South-East America continental margin is mostly flat seafloor in areas shallower than 1000 m so the vertical gravity gradient reveals basement structure not resolved before Swot. East of the 1000 m contour, the continental shelf is incised by river channels carrying sediment to the deep Argentine basin (deep blue linear structures). These features are now resolved globally including the Antarctic margins. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)
The South-East America continental margin is mostly flat seafloor in areas shallower than 1000 m so the vertical gravity gradient reveals basement structure not resolved before Swot. East of the 1000 m contour, the continental shelf is incised by river channels carrying sediment to the deep Argentine basin (deep blue linear structures). These features are now resolved globally including the Antarctic margins. (Credit Scripps Institution of Oceanography, courtesy Y. Yu & D. Sandwell)

No more than a quarter of the seafloor has been mapped by ships over all the oceans. Before, to fill in the gaps, marine gravity from satellite altimetry was used. However, it provides only low-resolution maps, and has problems with features such as abyssal hills, small seamounts, and continental margin structure. 
Swot is dramatically improving the accuracy and resolution of sea surface height measurements, thus enabling to better map these small-scale undersea structures. A team from Scripps Institution of Oceanography has processed 1 year of Swot KaRIn ocean level-2 data (using both calval and science orbit) to extract the, which is the curvature of the ocean surface. As mentioned in Image of the Month, May 2024: Swot measurements help in seafloor mapping, a small bump in the ocean surface can be produced by a local increase in the pull of gravity due to extra mass. This enables to retrieve bathymetric highs associated with, for example, ridges or seamounts, which have an extra mass relative to the surrounding seafloor. 
The use of another year or more of Swot science orbit data will further reduce the noise in the global vertical gravity gradient maps, and thus improve even more the resolution of seamounts, abyssal hills, and continental margins. This marine gravity will also be combined with available depth soundings, using machine learning methods, to dramatically improve global bathymetry, especially in the remote oceans.

This much better knowledge of bathymetry will support improved resolution models of ocean dynamics, including internal tides, as deep tidal currents flowing over rough abyssal hill produce internal waves, especially along rough slow spreading ridges. 

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