Salt-wedge observations in ضresund by direct measurement of the motionally induced voltage

Measurements of the cross-channel voltage in the Öresund between Sweden and Denmark, where a salt wedge was present, showed that baroclinic phenomena can be studied occasionally by direct measurements of the “motionally induced voltages” (generally used for monitoring barotropic flows). Making use of the fact that the lower layer was almost passive since the salt wedge was topographically arrested, it became possible to calculate the thickness of the upper active layer. The evolution in time of this quantity showed oscillations associated with the barotropic tide, whereas its overall features mirrored the bulk flow through the passage. Furthermore, it was found that the tidally induced velocity fluctuations in Öresund propagate northward towards Kattegat in the form of a kinematic wave.