SWOT Mission Validation of Sea Surface Height Measurements at Sub-100 km Scales

After two decades of development, the Surface Water and Ocean Topography (SWOT) mission launched on December 16, 2022, pioneering the use of Ka-band Radar Interfer24 ometry (KaRIn) for measuring water surface elevation and achieving two-dimensional altimetry on two 50 km swaths separated by a 20 km nadir gap. Rigorous validation against in-situ observations in this study demonstrates that KaRIn achieves enough accuracy to resolve sub-100 km oceanic processes, with measurement errors 2-4 times smaller than anticipated. These results confirm SWOT’s transformative capabilities for advancing oceanographic research and establishing a robust foundation for future applications of the swath altimetry. The results also underscore the innovative advancements in mooring system design, driven by the stringent science requirements of the SWOT mission.