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The influence of wind on the surface waters of Alberni Inlet

University of British Columbia

Observations of wind, current and surface layer thickness in Alberni Inlet have helped elucidate some of the ways in which the system responds to a surface stress. The energy of the wind and also the current at 2 meters depth is strongly diurnal. Cross-spectral analysis has shown that the two are closely coupled at this frequency. On the basis of simple time scale considerations I have used phase angles between wind and current to estimate a bulk eddy viscosity for the upper two or three meters of the inlet. This method has yielded values between 1 and 10 cm²/sec. On the other hand most of the energy associated with changes in the surface layer thickness is of significantly lower frequency. Strong up-inlet winds induce a sudden thickening in the surface layer at the inlet head and the disturbance appears to propagate back down the inlet suffering an attenuation as it travels. The return to equilibrium can take several days. A simple two-layer frictional model is able to explain much of what is observed and can be used to predict the surface layer thickness on the basis of measured wind speeds.

Text

2011-03-17

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http://hdl.handle.net/2429/32542

Oceanography

University of British Columbia

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