Longshore Characteristics of Wave Run-up under Stormy Condition

Abstract

An X-band nautical radar system was employed to examine wave run-up during a typhoon around the research pier HORS in Hasaki, Japan. Analyses on radar echo images were done to estimate temporal and spatial variations of water fronts by manual digitizing of cross-shore time stack images. Digitized instantaneous water fronts were validated with wave gauge measurements with an acceptable agreement. Long-shore distribution of mean shoreline positions and intertidal foreshore slopes were then estimated using time averaged images. Run-up, the height of discrete waterlevel maxima, was estimated from the digitized water fronts with the help of foreshore profile. Run-up variationswere parameterized with surf similarity parameter. Low frequency variances in run-up motion were observed, whichwere traveling in the longshore.