Meteotsunamis in the Mediterranean Sea: rare but destructive extreme sea level events occurring under specific synoptic conditions Ivica Vilibić, Jadranka Šepić Institute of Oceanography and Fisheries, Split, Croatia,  About meteotsunamis  Mediterranean events  Connection to the synoptics  Some conclusions and perspectives

About meteotsunamis Sea Level Workshop, Palma, June 2015  Highly resonant phenomenon, very rare occurrence at destructive levels Šepić et al., Sci. Rep., 2015

About meteotsunamis Sea Level Workshop, Palma, June 2015  Driven by travelling air pressure disturbances (occasionaly winds) Vilibić et al., JGR, 2004 Vilibić et al., PAGEOPH, 2008

Mediterranean events Sea Level Workshop, Palma, June 2015 milghuba šćiga marrobbio rissaga  Recorded at different Mediterranean locations and basins

Sea Level Workshop, Palma, June 2015 Mediterranean events  Some events: Vela Luka, Croatia, 21 June 1978  6-m waves at the top of the bay

Sea Level Workshop, Palma, June 2015  Some events: Vela Luka, Croatia, 21 June 1978  6-m waves at the top of the bay Mediterranean events Vučetić et al., Phys. Chem. Earth, 2009

Sea Level Workshop, Palma, June 2015  Some events: Ciutadella, Spain, 15 June 2006  5-m waves at the top of the bay, strong currents Tens of sunk and damaged yachts, loss of ~30 MEuro. Mediterranean events Monserrat et al., NHESS, 2006

Sea Level Workshop, Palma, June 2015  Normally occurring locally at destructive levels, encompassing a few tens of kilometres at most  bays of Mali Lošinj and Ist (distanced by 50 km) were not hit by a meteotsunami at the same time 21 June 1978 Vela Luka (~6 m) 5 October 1984 Ist (~4 m) 27 June 2003 Stari Grad (~3.5 m) Mali Ston (currents) 22 August 2007 Ist (~4 m) 15 August 2008 Mali Lošinj (~3 m) 25 June 2014 Vela Luka (~3 m) Stari Grad (~1 m) Vrboska (~1.5 m) Rijeka dubrovačka (~2.5 m, currents) Mediterranean events

Sea Level Workshop, Palma, June 2015 Mediterranean events  Small changes in disturbance speed may end up in several times different wave heights  extremely sensitive to resonant conditions Šepić et al., JGR, 2015

Sea Level Workshop, Palma, June 2015  However, exceptional events may occur over thousand of kilometres  Fresh example of June 2014 (Šepić et al., 2015)  A series of destructive meteotsunamis hit the Mediterranean and Black Seas, following a peculiar atmospheric setting at synoptic scale Mediterranean events Šepić et al., Sci. Rep., 2015

Sea Level Workshop, Palma, June 2015  27 June 2014: 2-m wave injured 12 people in Odessa  Due to Ukrainian situation, extraordinary explanations flooded the media Mediterranean events

Sea Level Workshop, Palma, June 2015  The event was connected to a propagating upper troposphere "storm", giving rise to a numerous air pressure disturbances ("boiling atmosphere") Connection to synoptics Šepić et al., Sci. Rep., 2015

Sea Level Workshop, Palma, June 2015  A half of moderate and strong meteotsunami events observed on the Balearic Islands are followed by similar events in the Adriatic Sea within 1-2 days Connection to synoptics Šepić et al., Phys. Chem. Earth, 2009

Sea Level Workshop, Palma, June 2015 Connection to synoptics Šepić et al., JGR, 2012  That was already recognized in research of the Balearic and Adriatic meteotsunamis  quite useful for creation of a warning system  however, only qualitative forecasts may be issued  Below: Average SLP, T at 850 hPa and winds at 500 hPa reanalysis fields for 16 events at Rovinj (Adriatic)

Sea Level Workshop, Palma, June 2015 Connection to synoptics  Confirmed by numerical modelling (atmosphere)  Below: air pressure and winds during the 2007 ist meteotsunami as reproduced by the WRF mesoscale model 22 August 2007, 15:12 UTC Šepić et al., JGR, 2009

Sea Level Workshop, Palma, June 2015 Connection to synoptics  In general, high-frequency sea level oscillations in the Mediterranean (not only meteotsunamis) may be attributed to synoptic patterns  Details may be found on the poster by Šepić et al. Šepić et al., Prog. Ocean., 2015, under review

Sea Level Workshop, Palma, June 2015 Some conclusions and perspectives  Ocean physics during meteotsunamis well understood and reproduced by ocean models  Atmosphere physics a less well understood, but quite hard to reproduce by numerical models  a need for better knowledge on gravity wave generation and propagation in the atmosphere  Connection to a propagating synoptic patterns exists  useful for warning systems  also useful for assessing long-term and future meteotsunami potential from climate models  Efficient meteotsunami warning systems are still far from operational, but a concept of such a system is developable  based on an assessment of synoptic conditions, real-time high- frequency air pressure measurements and remote sensing data (satellites, HF radars)