On December 16, 2022, the NASA/CNES Surface Water Ocean Topography (SWOT) satellite mission was successfully launched and has since been capturing the height of the ocean (sea surface height or SSH) at unprecedented spatial scales between 78°S and 78°N. With SWOT, we are able, for the first time, to observe SSH at resolutions below 10 km while conventional satellite altimeters have been capturing the height of the ocean at scales of ~300 km in the 1990s to ~100 km at present. Capturing the topography of the ocean surface at fine scales is necessary to effectively monitor the ocean dynamics that contribute to the vertical transport of heat and carbon within the ocean as well as coastal sea level. This will in turn help scientists to improve the understanding of climate change and its consequences on the environment and society. However, challenges do exist. With the high-resolution (2 km) but narrow swath (120 km), SWOT needs 21 days to map the global ocean. Filling the missing information in the big temporal gaps becomes one of the biggest challenges in maximizing SWOT’s potential.

The animation shows one of the first full cycles of SSH anomalies acquired by SWOT in August 2023. The height of the sea surface has highs (red) and lows (blue) affected by ocean tides, waves, eddies and currents. It takes 21 days for the SWOT satellite to sample almost all of the ocean surface while a conventional altimeter such as Sentinel-6 Michael Freilich will do that in only 10 days (albeit at a lower spatial resolution). The longer repeat cycle of SWOT presents some challenges as some features, such as fronts and eddies that persist for short periods of time, could be missed by the satellite. Moreover, while the unprecedented resolution of SWOT observations will allow us to observe oceanic features that have never been seen before, prior work needs to be done in order to identify the true signals observed. It is and will be necessary for the community to advance the current knowledge and to put forward innovative ideas and solutions such as artificial intelligence to make use of these unprecedented observations provided by the mission.

Dataset NameProcessing
Start/StopFormatSpatial ResolutionTemporal
SWOT Level 2 KaRIn Low Rate Sea Surface Height Data Product, Version 1.12 to PresentNETCDF-42 Kilometers x 2 Kilometers