CoAuthors

Graham Quartly (Plymouth Marine Laboratory, United Kingdom); Daniel Conley (University of Plymouth, United Kingdom); Wei Zhang (University of Plymouth, United Kingdom)

Due to the smaller ground footprint and higher spatial resolution of its SAR mode, Sentinel-3 SRAL observations are expected to resolve signals associated with dynamical processes smaller than the large mesoscale eddies (order of 100 km) as well as to have improved performance in coastal areas. These two features are assessed in the coastal region of southwest England. The region is particularly well suited for the task due to the presence of various moored buoys which provide continuous time-series of metereological and surface ocean variables, as well as an array of HF radars which provides 2-dimensional surface currents on a hourly basis.

Observations from the buoys are used to evaluate Sentinel-3 performance in retrieving significantwave height from the shape of the returning echoes. The buoys include the Western Channel Observatory buoy moored in front of the Plymouth Sound, and the Sevenstones and WaveHub buoys moored west of Cornwall. These locations provide a broad range of wave height and swell conditions against which to validate Sentinel-3 observations.

HF radar observations are used to assess both Sentinel-3 significant wave height and across-track surface geostrophic currents. Radar observations extend for ~100 km off the northwestern coast of Cornwall, providing a 2-dimensional field which is used to assess Sentinel-3 performance not only on a point-to-point basis but also in terms of reconstructed spatial patterns. Furthermore, 2-dimensional observations are used to investigate to which degree the accuracy of Sentinel-3 observations is associated with given velocity patterns or swell characteristics.