Naslov
Recent findings on meteotsunamis in the Middle Adriatic

Autori
Vilibić, Ivica

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
Book of Abstracts / Ziang, Xiuhua ; Lilja Bye, Bente ; Vilibić, Ivica - Split : Hrvatski hidrografski institut (HHI), 2005

Skup
Workshop on Sea Level Variations Toward an Operational European Sea Level Service

Mjesto i datum
Split, Hrvatska, 05.10.2005. - 06.10.2005

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Nije recenziran

Ključne riječi
sea level; tsunami; air pressure; resonance

Sažetak
A few novel things on resonant coupling between travelling atmospheric disturbances and the sea - so called meteotsunamis - in the middle Adriatic coastal waters are discussed in the work. First, two episodes of large high-frequency sea level oscillations (< 5 h), occurred in June 2003 and August 2004, are compared. Both cases were characterized by rather sharp changes in air pressure, but with different shapes of the disturbance. Also, strong winds occurred during the August 2004 episode, not recorded in June 2003. The flood and vigorous currents were documented in June 2003 in some bays and harbours, while no flooding happened in August 2004. Occurrence of a strong 4-hour oscillation versus weak harbour seiches (10-30 min) in August 2004 was hypothesed to be a result of the shape of travelling air pressure disturbance: it looked like a smoothed box-function containing large energies in a low frequency domain. Oppositely, the event in June 2003 was characterized by a cosine-like disturbance, redistributing the energy towards higher frequencies (maximum at 80 min). All of these findings were reproduced by nonlinear barotropic model which was forced by different travelling disturbances and winds. Next, a set of idealised numerical experiments were constructed to support the sensitivity of the sea response to the different air pressure travelling disturbances travelling with different velocities over the middle Adriatic coastal waters. Larger resonant transfer of energy is documented for shorter disturbances and for box versus cosine one, especially in the high-frequency domain. Bands of enlarged sea level amplification is found in front of Stari Grad Bay (6.7 and 11.0 min) close to its natural modes (6.1 and 10.6 min), what may be a reason for very large amplification and sporadic severe floods observed at the inner bay area. Finally, the energy of the meteotsunami during one year is modelled and compared to the single artificial tsunami event. It is shown that, if the whole meteotsunami energy during a year is concentrated in a single tsunami event, the waves in some bays may exceed 10 m height. Fortunately, it is not realistic scenario, but it emphasized the strength (and the weakness) of meteotsunamis in the area.

Izvorni jezik
Engleski

Znanstvena područja
Geologija

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