Detection of short-period sea level oscillations in the Gulf of Genoa

Abstract

Long-term time series of high frequency sampled sea level data collected in the Port of Genoa are analyzed to investigate the sub-daily variability. Spectral analysis evidences a well developed energy peak on 20–30 minutes band. Oscillations on this frequency band, the so-called meteo-tsunami, are an almost frequent feature in the analyzed signal. Their amplitudes are generally of few centimeters but, sometimes, they can reach higher values. On the contrary, seiches oscillations, whose period in the Ligurian Sea is 2.6 hours, are hardly detected. The occurrence of relevant meteo-tsunami events having amplitude higher than the maximum tidal elevation was then highlighted using time-frequency analysis. The more important event occurred on October 2016 when oscillations reached an amplitude of 50 cm and lasted for about three hours.