First Insights From SWOT Fast Sampling Phase: High Frequency Coastal Trapped Waves Over the Patagonian Shelf

Abstract The wide and highly productive Patagonian Shelf (PS) hosts a variety of waves. The study of Coastal Trapped Waves with periods smaller than 20 days has been limited by the temporal resolution of satellite altimetric data. The fast sampling phase of the recently launched Surface Water and Ocean Topography (SWOT) satellite revisits specific areas once a day and provides an unprecedented opportunity to examine rapidly changing signals over the PS. SWOT provides evidence of waves with wavelengths larger than 4,000 km and periods between 8 and 10 days which propagate with speeds of 5–6 m/s over the Pacific side and 10–13 m/s over the PS. They represent a major feature of the 20‐day high‐pass filtered sea surface height anomaly variability of the fast sampling phase. Wind bursts along the Pacific side probably contribute to their generation.