Proxy-based assessment of strength and frequency of meteotsunamis in future climate

Abstract

A climate synoptic meteotsunami index has been constructed using synoptic variables for the Balearic Islands. The index allows for the very first assessment of atmospherically driven intense sea level oscillations at the tsunami timescale (<2 hr) in future climates. The index has been computed using outputs from evaluation, historical, and three scenario MED-11_CNRM Med-CORDEX regional atmospheric climate runs. The reliability of the index has been verified against reanalysis simulations and on documented meteotsunami events. No significant changes in the index are projected under RCP2.6 and RCP4.5 scenarios, while the yearly number of days with meteotsunamis is expected to increase by 34% under the RCP8.5 scenario by the year 2100. This increase will dominantly occur during the summer season (May-August), being contemporaneous with maximum index values. The presented results are relevant for assessment of sea level extremes worldwide, since high-frequency sea level oscillations may contribute up to 40% of the total range.