Validation of 1‐Day Repeat SWOT Measurements Against Tide‐Gauge and Glider Data Off Canada's West Coast

Abstract The Surface Water and Ocean Topography (SWOT) satellite observations are shown to agree well with tide gauge and underwater glider data in the Northeast Pacific. The SWOT mission measures sea surface height in a 120‐km wide swath. It had a 1‐day repeat cycle for 3 months in 2023. The daily SWOT Level‐3, 2‐km non‐tidal data have a root‐mean‐square difference of 5 cm (about 20% of the total variance) from coastal tide‐gauge data. Wavenumber spectra from SWOT observations show good agreement with those from glider steric heights for scales as small as 30 km. Spectral slopes in the eastern boundary current transition zone have values close to the surface quasigeostrophic theory across the mesoscale (30–250 km) and submesoscale (15–30 km) bands. The study demonstrates the ability of SWOT in measuring coastal and offshore sea‐level variabilities at small temporal and spatial scales unachievable by conventional satellite altimetry.