Complex EOF analysis of ocean surface currents response to the severe tropical storm Lionrock measured with high frequency surface wave radar

The complex EOF analysis of ocean surface currents to the Lionrock is investigated using six days´ currents data measured by OSMAR in the southwestern Taiwan Straits. The analysis shows that the first three EOF modes account for 89.51% of the variance and are judged to contain the only statistically significant results, and are the main modes. The analysis has also provided insight into the dynamics and spatial structure of the ocean surface currents. Mode 1, which alone accounts for 81.01% of the variance, shows a clear correlation to the tidal currents. Mode 2, which accounts for 6.27% of the variance, mainly reflects the divergence information of surface ocean currents, and the diverging flows are approximately symmetrical about the track of Lionrock and the magnitude of the temporal coefficients at the typhoon period is much larger than that at pre-typhoon and post-typhoon periods. Mode 3, which accounts only 2.22% of the variance, mainly reflects the vorticity information induced by Lionrock.