Role of Infragravity Energy in Bar Formation in a Strong-Wind Bay: Observations from Seaford Beach, Port Phillip Bay, Australia

摘要

Measurements of the surf zone wave field and morphology were obtained from a multi-barred beach in a fetch-limited, strong-wind bay (Seaford, southeastern Australia) during both low- and high-energy conditions. Analysis of the infra-gravity energy present during high-energy events (onshore winds >7 ms~(-1)) revealed that it was broad-banded, consisting of a mixture of standing and progressive motions and displaying daily variations in standing wave length scales. Infragravity standing waves were therefore not considered significant to the formation and migration of bars at Seaford during this study, with bar behaviour during high energy events potentially attributable to either breaking wave-bed return flow and/or self-organisational mechanisms.