## 4 Results  
### Correlation of the Reanalysis, Wave Recorder and OBS Data  
Figure 2 shows a comparison of the time dependences of the atmospheric parameters obtained from the reanalysis data, the sea level fluctuations in the frequency band 0.05-0.5 Hz [40], related to the wind-generated gravity sea waves obtained from the wave recorder data, as well as the ground velocity fluctuations obtained from the Typ2 OBS hydrophone and seismometer records. Since the reanalysis data are hourly, the averaging of the wave recorder and seismometer data was also carried out in hourly windows. The curves corresponding to the seismometers' data were also additionally smoothed in a moving average window (30,000 points). The semi-transparent colored numbered rectangles indicate the specific time periods, characterized by a certain pattern. The blue rectangle 1 corresponds to the period of time when the sea was free of ice--this can be seen from the ice concentration curve. During this period of time, the wave recorder, hydrophone and seismometers data curves correlated well with the wind speed curves. The peak positions of the curves are in good agreement with each other. The red rectangle 2 corresponds to the period of time of rapid ice formation, and also a sharp decrease in the amplitudes of sea level fluctuations and the level of seismic noise on all seismic sensors. The yellow rectangles 3-5 indicate the time intervals of a remarkable and rather long increase in the amplitudes of sea level fluctuations and seismic noise level within the period when the sea was covered with ice. These time intervals coincide with the moments of short but sharp wind speed increase above 14 m/s and also with a short but sharp drop in atmospheric pressure. Figure 3 shows the spectrograms of the ambient seismic noise obtained from the records of the OBS seismometers at the St3 and Typ2 sites. Colored arrows indicate the notable spectrogram features. First, the spectrograms also clearly show the differences  
Figure 2: Time histories of atmospheric and ice parameters (atmospheric pressure, wind speed and ice concentration) obtained from the ERA5 [26] and EUMETSAT [27] reanalyses, and their correlation with time histories of the averaged absolute values of the sea level fluctuation obtained by the wave recorder RBR virtuoso\({}^{3}\), the smoothed averaged amplitudes of the hydrophone pressure, and three components of ground velocity obtained by OBS at the Typ2 site. Semi-transparent colored numbered rectangles indicate the specific time periods, described in the text. between the period of time when the sea was ice-free and the period when the sea was covered with ice. The absence of ice is reflected in a pronounced signal amplification in the low-frequency ranges of 0.1-0.2 Hz and 0.3-1.5 Hz. On the spectrograms corresponding to the St3 site, the signal amplification in the frequency range 0.1-0.2 Hz is more pronounced than in the range 0.3-1.5 Hz, while on the spectrograms corresponding to the Typ2 site, the opposite is true. This is explained by the fact that the CME-4311 seismometers at the St3 site are broadband, and the CME-3311 sensors at the Typ2 site are short-period with a fundamental frequency of 1 Hz. Due to the fact that the sensitivity of the CME-3311 sensor at frequencies below 1 Hz does not decrease immediately, signal amplification is still present down to 0.1 Hz. The yellow arrows indicate the boundary between ice-free and ice-covered time periods. Figure 3: The spectrograms of the ambient seismic noise obtained from the records of: (**a**) 1-st horizontal sensor CME-4311 at the St3 site; (**b**) 2-nd horizontal sensor CME-4311 at the St3 site; (**c**) vertical sensor CME-4311 for the St3 site; (**d**) 1-st horizontal sensor CME-3311 for the Typ2 site; (**e**) 2-nd horizontal sensor CME-3311 for the Typ2 site; (**f**) vertical sensor CME-3311 for the Typ2 site. Colored arrows indicate the features of the spectrogram, described in the text.