Characteristics of Wave Properties in the Macro-tidal Surf Zone Observed by Remote Imaging Methods

Abstract

Most of earlier field studies on nearshore wave processes have been conducted at the areas of wave dominant coastal environments in simple bathymetric conditions in which non-wave-induced currents such as tide-induced currents are negligible. Whereas, intensive field experiments at a macro-tide environment (i.e. the Malipo sand beach located in the west coast of Korea, having a wide inter-tidal range spanning up to 1 km in the seaward direction) were recently carried out in winter seasons (December, 2008 and 2009 (planned)) to investigate the complicated interactions of coastal waves, coastal currents, and nearshore bathymetries. Particularly, the characteristics of shallow water wave properties (i.e. wavelength, wave period, and wave celerity) in interaction with the tidal currents and nearshore bathymetries were analyzed here using the in situ measurements and remotely recorded nearshore image data, and compared to the theoretical wave formulations such as shallow water dispersion relations and shallow water celerity theories. Technically, the transformations of the wave properties in and near the surf zone were quantified in the cross-shore direction by tracking individual waves in the 2-D (spacetime) cross-shore image timestacks generated along a 1-D cross-shore transect in the image sequences determined through the locations of the in situ sensors.