Dynamics of Barred Shore Profile on the Temporal Scale of a Storm Cycle

Abstract

A model is developed to simulate the morphodynamics of a barred shore profile on the scale of a storm cycle, comprising the phases of high and low wave activity. In the CROSS-PB model, the main mechanisms governing sediment transport in wave shoaling and surf zones are taken into consideration, in particular, skewness and asymmetry of the wave orbital velocities, undertow, and infragravity oscillations associated with wave groups. By comparing calculations with observed data, it is concluded that the model correctly reproduces seaward displacement of bars during a storm and shoreward under moderate or weak wave conditions. The first process is shown to be provided by balance of transport mechanisms when the peak offshore transport is located at the front slope of bar. The second process is conditioned by dominant shoreward transport and its sharp decay over the bar crest. Testing of the model yields estimates for the calibration coefficients, and it is concluded that shoreward sediment flux is mainly controlled by wave asymmetry.