The Surface Water Ocean Topography (SWOT) Mission and Marine Applications of Satellite Radar Altimetry for Societal Benefit

Continuity in the reference satellite radar altimetry missions (TOPEX/Poseidon; Jason 1, 2, and 3; Sentinel 6 Michael Freilich) involving partnerships between NASA and other space agencies over three decades has ensured an invaluable, cross-calibrated climate data record of key variables including sea surface height and water topography on large lakes and rivers, to significant wave height, surface ocean wind speed, and sea ice height and thickness. These observations have been instrumental to our improved scientific understanding of global ocean circulation, sea level rise and water cycle processes more generally. Importantly, they have also contributed to a growing number of practical applications involving operational government agencies and the private sector. These range from weather prediction, coastal impact assessment and planning, fisheries management, marine transport, and disaster risk management related to sea level change and flooding, among others. Launch in December 2022 of the joint NASA and CNES Surface Water Ocean Topography (SWOT) mission with its innovative wide-swath (120 km) Ka-band radar interferometer and complementary Jason-class nadir altimeter instruments, will provide observations of water surface topography over the oceans, coasts and land (rivers, lakes, wetlands) at unprecedented resolution that are likely to be a game-changer for science and decision support applications alike. Here we provide an overview of the SWOT mission, data validation, availability and access aspects, in addition to the targeted applications being developed via engagement with international partner organizations under the SWOT Early Adopters program.