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To study the features of short-period meteorological sea level oscillations, adaptation of the numerical Princeton Ocean Model (POM) to the Black Sea conditions was performed. The created diagnostic model adequately reproduces the statistical characteristics of mesoscale sea level variability in the Black Sea. Using the model, estimates of the periods of natural sea level oscillations of the Black Sea (10.7, 5.8, 4.9, 4.1 h) were obtained and the spatial distribution of their relative amplitudes and phases was calculated. Numerical experiments made it possible to estimate the separate contribution of changes in atmospheric pressure and wind stress to the formation of the Black Sea level variations. Changes in atmospheric pressure are the main driving factor in the formation of meteorological sea level oscillations in most of the Black Sea. The prevailing role of wind in the formation of sea level was found for the Sea of Azov and on the northwestern part of the Black Sea coast. [ABSTRACT FROM AUTHOR]

An analysis of hourly tide gauge observation data yields time-frequency estimates of storm surges in the Gulf of Finland. Spectral analysis of long-term series made it possible to identify the main periods of natural oscillations in the Gulf of Finland. As a result of the spectral-temporal analysis of individual floods, the time-frequency spectra of storm surges were obtained. For the Gulf of Finland, dangerous storm surges have periods of 25–35 h. Thus, the period of sea level oscillations during the flood of January 1, 1984, was 26–34 h; in December 1986, 24–34 h; in mid-October 1994, 24–30 h; in November 1999, 27–34 h; and in January 2007, 25–30 h. In the case of floods in early October 1994, oscillations with longer periods prevailed: 48–80 h. For the flood on January 9, 2005, caused by passage of the Gudrun cyclone, sea level fluctuations had periods from 27 to 48 h. In some storm surge cases, an increase in high-frequency 8-h oscillations is observed. The most unfavorable conditions for the formation of extreme storm surges in the gulf are the cases of passage of a chain of atmospheric cyclones with a period of about 1–2 days. Such cases lead to the resonant "rocking" effect of natural oscillations in the Gulf of Finland with a period of 26–29 h. It is shown that background mean sea level variations with periods of more than 20 days contribute to flood formation in the Gulf of Finland. Four events were identified when the mean sea level exceeded 100 cm for several days, three of which were accompanied by floods. [ABSTRACT FROM AUTHOR]

The object of the present study is mesoscale sea level oscillations in the Caspian Sea being the largest inland water body on the Earth. The main forces inducing sea level oscillations in this frequency range are variations in air pressure, wind stress, and tidal potential. These factors form a wide range of the Caspian Sea level variability including storm surges, seiches, and tides. To investigate the features of these oscillations, the POM (Princeton Ocean Model) numerical model was adapted to the Caspian Sea conditions. The tide-generating force in the equations of motion was specified through the tidal potential gradients over the Caspian Sea area. NCEP/CFSR reanalysis data are used to calculate meteorological impacts on the sea surface (wind stress and air pressure). The numerical model simulates well the statistical characteristics of mesoscale sea level variability in the Caspian Sea including seiches and tides. [ABSTRACT FROM AUTHOR]