Explaining asymmetries in the tidal response of the Dutch Wadden Sea

Abstract

In this research we aim to explain the asymmetries observed in the tides of the Dutch Wadden Sea. The observed tides are asymmetric in the water-height as it has are more constant longer lasting high tide, while the low tide changes much more quickly and lasts shorter. It is also asymmetric in time as the tide rises quicker during flood than it falls during ebb. We will identify these asymmetries in measurements taken from the Wadden Sea as well as quantify both asymmetries. We then aim to explain the causes of these asymmetries by approximating the tidal response of the Wadden Sea by a Helmholtz resonator. Using this approach we determine the effect on the water-height and time asymmetries of certain parameters, including basin shape, external driving and damping. Combining these results we conclude that the basin shape is responsible for the asymmetry in the water-height and the frequency of the external driving and quadratic damping terms both produce aspects of the observed time asymmetry.