Rhythmic beach and nearshore topography: examples from Denmark

Abstract

Aagaard, Troels: Rhythmic beach and nearshore topography: examples from Denmark. Geografisk Tidsskrift 88:55–60. Copenhagen. 1988.

Aerial photographs of nearshore bar features in Denmark have been studied and rhythmic wavelengths have been determined from a number of locations. From a knowledge of the profile characteristics, hypothetical standing edge wave periods, corresponding to the rhythmic length scales of the bars were calculated. It was found that the considerable range of rhythmic wavelengths on a given locality often may be explained as being the result of standing edge waves with a rather narrow frequency range, but of variable mode numbers. The frequency range of these edge waves often corresponds to a theoretical cut-off period given by the profile characteristics. This topographically induced cut-off may be an important parameter in the selection of frequency and structure of standing edge waves.

Keywords:

• Crescentic bars
• Edge waves
• Frequency selection