Seiches in Petrozavodsk bay of the lake Onego

The analysis of observation data on fluctuations in the level and velocity of currents in the Petrozavodsk Bay of Lake Onega, performed in 2016–2017, was carried out. Level oscillations were measured with a discreteness of 10 s using two TDR-2050 devices (RBR Ltd., Canada). Spectral analysis was performed using the simple Fourier transform method after one-minute data averaging to reduce instrument noise. Energy-carrier periods corresponding to the seiches of Petrozavodsk Bay and the Lake Onega are identified. Current velocities were measured with Aquadopp HR-Profiler (Nortek, Norway). Within the framework of the linear long wave theory, seiche oscillations are considered in a model basin approximating the Petrozavodsk Bay with regard to the Ivanovskiye Islands. Using an analytical solution, estimates for the periods of the higher seiche modes and the corresponding maximum wave flow velocities are obtained for the Petrozavodsk Bay. The comparison of theoretical estimates with the data of field observations, was showed satisfactory agreement.