First Views from Water-Tracking Satellite

The Surface Water and Ocean Topography mission has sent back some of its first glimpses of water on Earth’s surface, including a detailed view of the Gulf Stream.

The international Surface Water and Ocean Topography (SWOT) mission—led by NASA and the Centre National d’Études Spatiales (CNES)—has sent back some of its first glimpses of water on the planet’s surface, showing ocean currents like the Gulf Stream in unprecedented detail.

This image (top), produced with data acquired by SWOT on January 21, 2023, shows the sea level in a part of the Gulf Stream off the coast of North Carolina and Virginia. The two antennas of SWOT’s Ka-band Radar Interferometer (KaRIn) instrument acquired data that was mapped as a pair of wide, colored strips spanning a total of 75 miles (120 kilometers) across. Red and orange areas in the images represent sea levels that are higher than the global average, while the shades of blue represent sea levels that are lower than average.

First Views from Water-Tracking Satellite

For comparison, the new data is shown alongside sea surface height data (above) taken by space-based instruments called altimeters. The instruments—widely used to measure sea level—also bounce radar signals off of Earth’s surface to collect their measurements. But traditional altimeters are able to look only at a narrow beam of Earth directly beneath them, unlike KaRIn’s two wide-swath strips that observe sea level as a two-dimensional map.

NASA Earth Observatory images by Lauren Dauphin, using SWOT data provided by Shailen Desai/JPL and sea surface height data courtesy of the Copernicus Marine Service. Bathymetry data is from the General Bathymetric Chart of the Oceans (GEBCO). Story by Jane Lee/JPL