Meteotsunamis of the Black and Azov Seas

The conditions for the occurrence and development of the meteotsunami events of May 7, 2007, on the northern Bulgarian coast, June 27, 2014, near Odessa and in the port of Illichivsk (Sukhoi Liman), and July 19, 2017, in the waters of the Belosarayskaya Spit in the Sea of ​​Azov were analysed. All events occurred under similar macroscale synoptic conditions over southeastern Europe: according to Rabinovich's classification, these were "good weather" meteotsunamis. Due to the fact that in the Sea of ​​Azov and in the western part of the Black Sea there is a lack of a sufficient number of high-precision observation points for sea level and atmospheric pressure, determining the mechanism for generating sharp fluctuations in sea level causes certain difficulties. To identify visual observations of tsunami-like sea level fluctuations necessary and sufficient conditions have been determined, the fulfilment of which can give us confidence in determining the nature of the observed sea level fluctuations as generated by atmospheric processes – a meteotsunami event. The necessary conditions for the occurrence of a “good weather” meteotsunami in a coastal area should be considered the presence of a wide sea shelf.  Such shelf areas in the Azov-Black Sea region exist in the Sea of ​​Azov and only in the western Black Sea (the coasts of Bulgaria, Romania, and Ukraine). The topography of the Azov Sea bottom suggests that the velocity of a tsunami-generating atmospheric formation should not exceed 10 m/s. For the Belosaraysk meteotsunami, this conclusion is supported by satellite data on the movement of the corresponding convective cell.  To determine the sufficient condition for the occurrence of a meteotsunami, one must consider the meteorological, or more precisely, the synoptic, aspect of the meteotsunami generation process. Rabinovich and Šepić called this synoptic situation for the mesoscale region under consideration a "tumultuous atmosphere." What this term implies is that the sufficient condition should not be considered to be a specific atmospheric gravitational disturbance, but rather the specific structure local atmosphere. A comparative analysis of synoptic charts on the specified dates the meteotsunami occurrence for the Azov-Black Sea region reveals a classic pattern of frontal interaction between the Lesser Asian Depression (with dry and very warm air of African origin) and the cold and moist (polar) air of the anticyclone over Eastern Europe. A good qualitative correspondence is noted between the structure of the pressure fields and the location of fronts and zones of convective cloud cover. Aerological data indicate an influx of warm and dry air into the lower troposphere, resulting in an inversion in the surface temperature field, as well as the presence of fairly strong wind speeds in unstable atmospheric layers.