Seiches in Petrozavodsk Bay, Lake Onega

Resumo

Data of field measurements of water level variations and current velocities in Petrozavodsk Bay, Lake Onega, made in 2016–2017, are analyzed. Water level variations were carried out with a step of 10 s by two instruments TDR-2050 (RBR Ltd., Canada). Spectral analysis was made by simple Fourier transformation after one-minute averaging of data to reduce instrumental noise. Energy-bearing periods corresponding to the modes of seiches of Petrozavodsk Bay and Lake Onega were identified. Flow velocities were measured by instruments Aquadopp HR-Profiler (Nortek, Norway). A linear approximation of the theory of long waves was used to analyze seiche oscillations in a model bay approximating Petrozavodsk Bay with the Ivanovskie Islands taken into account. An analytical solution was used to evaluate the periods of larger modes of the seiches and the corresponding maximal velocities of wave currents for Petrozavodsk Bay. Theoretical estimates were compared with field data and showed a satisfactory agreement.