The influence of seamounts on ocean surface wave propagation in Northeast Brazil

General propagation patterns due to the multiple interaction of waves and seamounts located in Northeast Brazil are investigated using SWAN. After conducting a model sensitivity test using in situ data, four realistic cases (in which the maximum period of the incoming swells was 17.6s) and one synthetic case (using the maximum period as 21.3s) have been simulated. The incoming wave periods and the minimum seamount depth determine whether the interaction happens or not. When the interaction occurs, changes in wave direction, significant wave height (Hs), and shadow zone length increases with higher incoming wave periods. Shoaling and wave refraction occur concomitantly, leading to lower significant wave heights on the flanks of the seamounts and higher values of this variable over the shallowest parts. The observed wave alterations are also due to the topographic orientation of the seamounts’ shallower portion relative to the incoming wave direction and to the interaction between waves affected by more than one seamount. For the shallowest seamount in the study area (minimum depth of 21m), the maximum significant wave height increased 43.7% and 25.3% relative to the incoming wave heights for the synthetic and realistic cases, respectively.