Propagation Characteristics of Wave from South Atlantic to Gulf of Guinea in Winter

Abstract:

The detailed composition， propagation characteristics， and sources of waves from South Atlantic Ocean to Gulf of Guinea remain an unsolved problem. The temporal and spatial distribution of waves from South Atlantic to Gulf of Guinea in winter were simulated by constructing a two-layer nested wave model based on SWAN （Simulating WAves Nearshore）. The results suggest that the significant wave height decreases from high latitude （south of 30 ° S） to low latitude （north of 30 °S） in South Atlantic. There exists a close correlation between wave propagation direction and wind field in high latitude， but a significant distinction in low latitude. The distribution of swell is highly correlated with the mixed waves， and accounts for a large proportion of the mixed wave in South Atlantic， especially in the low latitude area with a low wind speed. There exists a stable S-SW swell system from the middle of South Atlantic to the Gulf of Guinea， and the simulated two-dimensional spectra shows concentrated swell wave energy in narrow directional distribution. The Gulf of Guinea is obviously swell dominated during the simulation period. The simulation study indicates that the swell system in maximum significant wave height event of the Gulf of Guinea during simulation period could be traced back to the strong wind and waves in the Roaring Forties in South Atlantic about 6.5 days ago.

Key words:sea wave;South Atlantic;Gulf of Guinea;Roaring Forties;SWAN(Simulating WAves Nearshore)