Surface currents on the Rottnest continental shelf, Western Australia

It was found that the surface currents only clearly follow the northbound Capes Current in times when the southerly winds of the daily sea breeze, the Fremantle Doctor, sets in. During periods of full cyclic directional rotations of the wind, Surface currents react within an hour to a change of direction of the wind, allowing southerly currents to dominate during strong northerly sea breezes, often followed by mixed currents. During storm events, the initially northerly winds, which persist for several days, followed by southerly winds (imitating a summer sea breeze), lead to a clearly southerly flow of surface currents, which do not react within an hour to the change of wind direction. This suggests that the longer duration of the wind in a consistent direction will have a stronger impact on the surface currents, forcing them to a deeper potential than the more short-lived cyclic rotations such as found when typical summer sea breezes occur. Summer and winter storm events have also been shown to have polar effects on local eddies, the winter storms leading to the decimation, summer storms encouraging the spin up. Comparison of complex correlation plots also showed a stronger correlation over the summer months (December-February) compared to the winter months (June-August) during which more storm events occur and the daily sea breeze cycle is less frequent and of lower force when it does occur. Conclusively, stronger winds have a larger impact on surface currents, leading to a stronger initial reaction of the currents, yet also a delay in subsequent direction changes. The surface currents react more quickly to the cyclic rotations of the sea breeze as these aren't as strong and are of shorter duration, allowing the utmost layers of the surface currents to adjust to the wind, leaving the currents at larger depths unaffected.