engleski

Meteotsunamis in the Mediterranean Sea: rare but destructive extreme sea level events occurring under specific synoptic conditions

This presentation will encompass state-of-the-art on meteotsunamis, rare but potentially destructive extreme sea level phenomenon which occurs in the tsunami frequency band. The tsunami-like waves are generated by atmospheric pressure disturbances propagating over a shelf, resonantly pumping energy into the ocean during those situations in which speed of air pressure disturbance equals speed of long ocean waves. These propagating atmospheric disturbances are normally associated with specific atmospheric conditions which enable generation and non dissipative propagation of low-tropospheric waves over long distances. Meteotsunamis have been documented to appear in coastal waters of all continents and world seas, with a substantial coastal impact in low-tidal basins such as the Mediterranean. Destructive meteotsunamis normally affect a limited area not wider than a few hundreds of kilometres ; however, the extreme events like the one occurring in the Mediterranean between 22 and 27 June 2014 may be composed of a chain of destructive events, affecting coastal regions over a few thousands of kilometres.In the Mediterranean, destructive meteotsuna mis are documented to occur in the Balearic Islands, the Adriatic Sea, western Sicily coast, the Maltese Islands and the western Black Sea coast, with several meters high waves occurring once in a decade. Meteorological tsunamis normally occur during warm seasons when inflow of warm and dry air from Africa is persistent in the lower troposphere, and when a strong and unstable mid-tropospheric south-westerly jet stream can become a dominant atmospheric feature, serving as a generating and reflecting layer for surface atmospheric disturbances over long distances. Damages to coastal infrastructure during destructive meteotsunami events can be up to several millions of Euros and higher, due to both destructive sea level waves and severe currents in harbour or bay constrictions. Meteotsunamis have also been suspected to be responsible for a loss of human lives in an event that hit Algerian coastline in August 2007. Less prominent high-frequency events, which cause no damage, but are registered on tide gauges, occur several times a year throughout the Mediterranean.

meteotsunamis; Mediterranean

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