Infragravity Waves at a Dissipative Shore with Multiple Bars: Recent Evidence

Abstract

This paper presents more precise evidence on the existence of infragravity waves at a dissipative coastal segment of the Baltic Sea in Poland. The waves were identified with recorded water levels from four gauges in close shoreline proximity, and detailed analyses focused on the output and patterns obtained through the use of discrete wavelet transform (DWT) and cross-correlation functions. As a result, two infragravity waves could be identified: a progressive wave with a period of 34 s, wavelength of 96 m, and a modal number (n = 2); and a standing wave with a period of 130 s, and a wavelength of 252 m, and a modal number (n = 0). The combination of DWT and traditional cross-correlation analysis can serve as a universal tool for nearshore hydrodynamic investigations. Also, this methodology can be applied by extending instrumentation and placing two more wave gauges to form a line of five devices; this potential follow-up research should determine the wavelengths and modal numbers with more precision. This study provides the spatial scales needed to place such additional devices.