The main motivation of this research is to assess the trends of storm recurrence for the time period from 1979 up to 2020 and to analyze the connection between storminess and large-scale atmospheric circulation indices. This research contains information about the number of storms that occurred in seven Russian Seas, including the Black, Caspian, Barents, Kara, Bering Seas, the Sea of Okhotsk and the Sea of Japan/East Sea. The analysis of wave climate and storm activity is based on the results of wave modeling by WAVEWATCH III with input NCEP/CFSR wind and ice data. The long-term significant wave height (SWH) maximum is 15.5 m in the Sea of Okhotsk and 16.5 m in the Bering Sea. Significant linear basin-wide positive trends in the number of storms were found in the Kara, Caspian, Bering, Okhotsk Seas, and in the Sea of Japan. The weak positive correlation was found only between the number of storms and North Pacific index in the Bering Sea and between the number of storms and Arctic oscillation index in the Barents Sea. For other seas, it is no connections between number of storms and large-scale atmospheric indices, therefore, storm activity in the inner and semi-closed seas is regulated by the local wind and ice conditions, basin orography and bathymetry.

The present study examines the seasonal and decadal changes of the variance of the synoptic (periods from 2 days to 30 days) and mesoscale (periods from 2 h to 2 days) sea level oscillations in the Baltic Sea. Long-term hourly sea level records were used at 12 tide gauges located in different parts of the sea. We used spectral analysis to estimate the variance for different time scales. The spectral density of sea level oscillations in the Baltic Sea has maximum values in winter when the cyclonic activity in the atmosphere is more intensive. The maximum variances of synoptic ${\sigma }_{syn}^2$ and mesoscale ${\sigma }_{mes}^2$sea level oscillations are observed in winter, except for the heads of the Gulf of Finland (Gorny Institute) and Gulf of Riga (Pärnu), where the absolute maximum of ${\sigma }_{syn}^2$ is reached in November. The variances ${\sigma }_{syn}^2$ and ${\sigma }_{mes}^2$from November to February are 2–3 and 5 times higher than in the summer. The values of ${\sigma }_{syn}^2$ and ${\sigma }_{mes}^2$ are characterized by high correlation up to 0.7–0.75 with wind variations and atmospheric indices (NAO, AO, and SCAND) in winter and low correlation in summer. The zonal wind and ${\sigma }_{mes}^2$ in Gorny Institute are characterized by wide areas of high coherence at periods of 0.7–4 years. At Gedser, ${\sigma }_{syn}^2$decreased by 19%, and at Ratan it increased by 17% over 90 years. The values of ${\sigma }_{mes}^2$ over 90 years increased by 32% at Klagshamn, 36% at Ratan, and up to 60% at Kungsholmsfort.

Two powerful earthquakes struck southeastern Turkey on 6 February 2023 with the magnitudes of M_w = 7.8 and M_w = 7.5 in nine hours. In addition, a storm surge caused by the passage of a cyclone over the area coincided with the first earthquake. Field observations showed that the fault planes did not extend to the Mediterranean Sea; however, a weak tsunami was observed on several tide gauges in the northeastern Mediterranean. Historically, there were tsunamis in the Levantine Sea region caused by earthquakes on land within the East Anatolian Fault Zone and the Dead Sea, having a complex cause, i.e., earthquakes and associated landslides. Hence, we studied the origin of the generated waves. We separated and estimated various components of sea level oscillations from 1 to 8 February 2023, using spectral and f-t analyses and sets of narrow-band and high-frequency filters. The earthquake M_w = 7.8 on 6 February 2023 caused a weak tsunami with maximum amplitudes 15‒17 cm in Erdemli and Arsuz. We identified that the increase in sea level oscillations in Arsuz after 7 February was associated with the impact of the cyclone. The maximum amplitude of sea level oscillations, 22 cm, in Arsuz was observed on 7 February and is associated with infragravity waves caused by the influence of storm surge during the passage of the cyclone. In Erdemli, on the contrary, the influence of high-frequency waves of atmospheric origin is significantly lower, i.e., the amplitude of the sea level oscillations after 7 February was less than 10 cm.

On 28 March 2005, a major M_w 8.6 earthquake occurred near Nias and Simeulueislands, in the vicinity of northwestern Sumatra (Indonesia). The earthquake generated a significant tsunami. Although it was not as destructive as the 2004 Sumatra tsunami, the 2005 event was of sufficient strength to be recorded by tide gauges throughout the entire Indian Ocean. We selected 12 records for analysis, most from open-ocean islands but also some from continental stations. The maximum wave heights were measured at Salalah (Oman) (87 cm), Colombo (Sri Lanka), Pointe La Rue (Seychelles) and Rodrigues Island (53–54 cm). The dominant wave periods, estimated from frequency–time (f-t) diagrams, were 60–66 min, 40–48 min, and 20 min, which we assume are associated with the 2005 tsunami source. From the same stations, we calculated the mean ratio of the 2004 to 2005 tsunami heights as 5.11 ± 0.60, with the maximum and minimum heights to the west and south of the source region as 9.0 and 2.49, respectively. We also used these data to estimate the mean energy index, $E_0$ = 65 cm², for the 2005 tsunami, which was 16 times smaller than for the 2004 event. The USGS seismic solution was used to construct a numerical model of the 2005 tsunami and to simulate the tsunami waveforms for all 12 tide gauge stations. The results of the numerical computations were in general agreement with the observations and enabled us to map the spatial wave field of the event. To estimate the influence of location and orientation of the source area on the propagating tsunami waves, we undertook a set of additional numerical experiments and found that this influence is substantial and that these factors explain some of the differences between the physical properties of the 2004 and 2005 events.