Observations of infragravity period oscillations in a small marina

High-frequency sea level oscillations in the Mediterranean and their connection to synoptic patterns

“…Such data have become available for research in the last decades through different data portals (e.g., the University of Hawaii Sea Level Center at http://uhslc.soest.hawaii.edu and the Permanent Service for Mean Sea Level at http://www.psmsl.org), with a standard temporal resolution of 1 h. Nevertheless, there are processes on time scales shorter than 2 h that can also contribute to sea level extremes and that are not captured by hourly measurements. These processes include the following: tsunamis (Papadopoulos et al, 2014), meteotsunamis , edge waves (Ursell, 1952) and infragravity waves (Thotagamuwage and Pattiaratchi, 2014). The effects of extreme sea level and the damaging of coastal infrastructure may be linked to these shorter-period processes, which may also be embedded into extreme storm events, especially within harbours and bays and over shelves where atmospherically generated open-ocean long waves are amplified by local topography (Gomis et al, 1993;Rabinovich, 2009) or are trapped close to the shoreline (Huthnance, 1975;Vennell, 2010).…”

New ways to measure waves and their effects at NOAA tide gauges: A Hawaiian‐network perspective

“…Wave ig associated with shelf dimensions (periods > 600 s) are more persistent and presumably a resonance driven by tidal energy [ Woodworth et al , ; Wijeratne et al , ]. The wave‐forced wave ig (harbor oscillations) are similar to those discussed by Thotagamuwage and Pattiaratchi [] in Two Rocks, Australia, and Park et al [] in Monterey, CA. Although Honolulu (Figure a) was sampled under smaller H s conditions (daily averages less than 1 m), its harbor appears a better spatial filter of wave inc energy as compared to Kahului (Figures b and b) and Hilo (Figure c), where large spectral peaks exist in wave inc bands during high H s events.…”

“…TG platforms are located at the land‐ocean interface (i.e., docks, seawalls, piers) and typically do not experience such swash‐related motions. A TG without consideration of its averaging scheme and physical dampening from its protective structure experiences more of a dynamic water level (DWL): where SWL is obtained from equation , α is an exceedance duration coefficient associated with the sampling period (e.g., 1.96 approximates the 95% of the Gaussian distribution) and sigma represents the standard deviation of the high‐frequency oscillations that directly impinge upon TG platforms from incident (wave inc ) wind waves/swell (periods of 5–25 s) generally attenuated in harbors by design and by longer‐period (25 s to tens of minutes) infragravity waves (wave ig ) often pronounced in harbors [ Thotagamuwage and Pattiaratchi , ; Park et al , ]. The magnitude of sigma is presumably dependent upon the TG location.…”

Measurements of Long Waves in Port of Klaipėda, Lithuania

“…Such situations are often induced by the impact of long waves or by resonance of the water motions in small basins such as harbors or marinas excited by shorter waves. The resulting water level fluctuations and extensive seiches can cause excessive movements of vessels, compromise harbor operations, create danger to vessels, harbor constructions and in extreme cases even loss of lives (Brázdil et al, 2010;Chen and Mei, 2006;de Jong and Battjes, 2004;Dragani et al, 2009;Rabinovich, 2009;Thotagamuwage and Pattiaratchi, 2014). For many harbors, the most important natural modes oscillation have rather long periods, from several minutes to an hour (Rabinovich, 2009).…”