Surface Water and Ocean Topography (SWOT) Vertical Gravity Gradient

Launched in December 2022, SWOT uses state-of-the-art phase-coherent interferometry to measure two-dimensional sea surface heights with high precision. Using 1 year of SWOT ocean data, we derive a global gravity field approaching a spatial resolution of 8 km, revealing more details than 30 years of satellite nadir altimetry. In this vertical gravity gradient map, individual abyssal hills, some spanning 200 to 300 kilometers, are now visible across ocean basins, along with thousands of small seamounts and previously hidden tectonic structures buried underneath sediments and ice. With the mission still ongoing, SWOT promises critical insights for bathymetric charting, tectonic plate reconstruction, underwater navigation, and deep ocean mixing.

Abyssal hills (in the Southern Indian Ocean of this visualization) are the most common landform on the ocean floor, rising a few hundred meters above the abyssal plain. Formed by normal faulting along mid-ocean ridge axes, these gently undulating hills were previously difficult to resolve at a global scale. The SWOT gravity map now reveals individual abyssal hills, enabling studies of plate reconstructions and the impact of rough topography on ocean mixing.

Seamounts (west of Central America in this visualization) are undersea volcanoes formed by magmatic intrusions through the oceanic crust. They shape ocean circulation, influence nutrient distribution, and serve as biodiversity hotspots. SWOT’s high-resolution mapping is expected to uncover approximately 50,000 previously unknown seamounts around 1 km in height, significantly enhancing our understanding of seafloor geomorphology.

SWOT offers unprecedented clarity at continental margins, particularly in high-latitude regions, revealing tectonic features buried beneath sediments and ice. For instance, it captures submarine canyons transporting sediments from land to the deep sea along the South American continental shelf, as well as ancient spreading ridges concealed beneath ice in the Weddell Sea.

See also: Earth Observatory Story

Here's a link to the video on youtube: https://www.youtube.com/watch?v=v5GJ4trliE4