Direct Measurement of Ocean Waves Velocity Field from a Single SPOT-5 Dataset

Abstract : We present a method based on space-borne optical imagery from the SPOT5 satellite to directly measure the phase velocity fields of ocean waves. The panchromatic and multispectral scenes acquired by SPOT5 the same day on the same area are not strictly superimposable due to the different locations of the CCDs (Charged Coupled Device) in the focal plane of the instrument. In this manuscript, we propose a method that exploits the temporal lag that exists between the panchromatic and multispectral scenes to measure the ocean wave velocity fields. We firstly discuss the principle and the methodology. Then, we apply it offshore La Reunion Island. Finally, we compare and discuss the results against a swell propagation model. Our method is proven reliable and can be immediately extended to other push-broom sensors.