The SWOT Postlaunch Oceanography Field Campaign L3 Moorings collection provides the surface air pressure, GPS, current velocity, and conductivity, temperature and depth (CTD) measurements from moorings at the L3 processing level. The SWOT satellite mission launched in late 2022 and underwent a calibration and validation (cal/val) phase in 2023. As part of cal/val, an array of oceanographic instruments was deployed at a site 300 km offshore of California, including moorings at 11 distinct sites. The S2 mooring site had additional re-deployments from an otherwise independent project to study internal waves, the National Oceanographic Partnership Program – Global Internal Waves (NOPP-GIW), beyond the cal/val phase from September 2023 to October 2024. Data from NOPP-GIW are included in this collection, and described here, because they are closely related to the SWOT cal/val efforts.

L3 data are gridded data on a consistent depth-time grid, whereby “depth” is given as pressure. Multiple versions, or layouts, of L3 data are disseminated for slightly different use cases as described in the user guide. L3 data are meant as the primary end-user datasets, and users should determine which version is most suitable for them. A user should consider what time resolution is needed, whether constantly spaced time steps are needed, and if data from more than one mooring at a time are needed.