SWOT observation of swell, Antarctica to Australia, June 10th 2023

This video shows swell resolved in SWOT SSH (in blue) and radar backscatter (grey shades) data, as the satellite flies along track 019 from Antarctica to Australia, on June 10, 2023, as part of cycle 547. The video starts at the edge of the sea ice and goes to the open ocean. Many "small" icebergs are visible as "pimples" in the backscatter data, e.g. around y = 280 km. There is a bigger iceberg at y=640 km. Note the dark patches (e.g. at y=1070 km) in radar backscatter are associated to rain cells. Swells are generally longer further away from the storm because long waves travel faster. Here the swell get shorter as we get closer to the coast of Australia indicating that these O(20 cm) high swells with wavelenghts between 500 and 700 m have been reflected from the shoreline. The incident swells can be seen on the previous day. The direction of propagation of the swell is confirmed by the cross-spectral phase between sigma0 and SSH: due to velocity bunching, the phase is shifted from 90 and 270° (tilt modulation) towards 0 if the waves travel in the direction opposite to the flight direction of the satellite. If the phase had been shifted toward 180°, then the waves would have been dominated by propagation in the same direction as the satellite. This swell is thus coming from storm Rosemary and reflected off Australia around Cape Leeuwin.