The Agulhas Current, with a mean transport of about 70 Sverdrup (1 Sverdrup = 106m3s-1), and surface current speeds, at times greater than 2 ms-1, constitutes the strongest western boundary current of the Southern Hemisphere.

Ocean waves Interacting with large-scale ocean currents is a frequent cause of sea-state variability. Such situations can lead to sea-state hazards, crucial for shipping security. The Great Agulhas current system is an area of very intensive maritime traffic, where dangerous localized sea-state amplificated by the current are regularly reported. One reason is the strong wave-current effects such as large refraction of waves by the oceanic current.

Here, we want to study and compare the difference between the ray swell propagation obtained using oceanic surface currents derived from the AIS and merged with the altimetry through MIOST with other product of current such as the classical DUACs estimates or the new product BFN (back and forth nudging). The focusing of the ray Swell will result in a cross-sea index which in turn can be compared to areas corresponding to vessels in distress.