Anomalous dispersion of fourier components of surface gravity waves in the near shore area

Water level deflections eta(t) have been measured synchronously at some positions in a beach profile on the isle of SYLT/North Sea during severe storm surge conditions as well as at attenuating wave action. A steadily increasing wave period T in the upbeach direction, turning out z from strip chart evaluations, is in accordance with the result of FOURIER syntheses. Near shore wave deformation is explained by ANOMALOUS dispersion of the frequency components