Meteotsunamis in the Western mediterranean: regional analysis from high frequency sea level observations

Meteotsunamis, or atmospherically generated tsunamis, can generate hazardous high frequency sea level oscillations in coastal regions. The inlet of Ciutadella, located on the western coast of Menorca (Balearic Islands), is a well-documented hotspot for meteotsunamis. In late spring and summer, Ciutadella frequently experiences sea level oscillations exceeding 1 meter, and occasional events of several meters have caused significant damage to boats and harbor infrastructures. Although Ciutadella has concentrated most of the attention, other locations across the Balearic Islands and the northeastern coast of the Iberian Peninsula also experience notable meteotsunamis.

This study examines the occurrence of meteotsunamis from a regional perspective, using all the available high-resolution tide gauge data with a 1-minute sampling rate collected over the past decades. The dataset includes contributions from operational tide gauge networks managed by Puertos del Estado, SOCIB, and PortsIB, the VENOM ultra-dense research network (operated by UIB, IEO-CSIC and UPC) and an individual tide gauge maintained by Josep Pascual at l’Estartit. In total, the analysis encompasses data from 27 instruments spanning the Balearic Islands and the northeastern Iberian Peninsula, with some time series exceeding 17 years and more than 10 series exceeding a decade.

Our regional analysis focuses on four key aspects: i) to characterize meteotsunami statistics across the study area including many locations that were not analysed before; ii) the contribution of the meteotsunami frequency band (1 min-2h) to sea level extremes; iii) a comparative analysis of meteotsunami events observed at different locations; and iv) the relationship between synoptic atmospheric patterns and meteotsunami occurrences. The findings reveal that high-frequency sea level oscillations are amplified in locations where topographic features favor the resonance of incoming meteostunami waves. While Ciutadella remains the primary hotspot, other locations such as Vilanova, Portocolom, and Port de Sóller also frequently experience significant meteotsunamis, which was not reported before. Moreover, we have found that sea level oscillations often occur simultaneously in several locations; the reason is that meteotsunamis are triggered by atmospheric disturbances associated with synoptic-scale meteorological patterns that cover a large part or the region, affecting several locations at the same time. Finally, the analysis highlights the challenges in predicting meteotsunami amplitudes. Their intensity is influenced not only by synoptic-scale atmospheric features but also by small-scale processes in the ocean and the atmosphere that are difficult to observe and predict. This complexity makes it challenging to establish robust amplitude relationships across locations or to issue accurate forecasts for the amplitude of meteotsunami events.