The Secondary Sea Level Maximum during Floods in Saint Petersburg and Its Simulation with Numerical Models

The study considered two- and three-dimensional models used to compute the Baltic Sea level. It is demonstrated for three floods that the BALT-P three-dimensional hydrodynamic model and the INMOM three-dimensional hydrothermodynamics model successfully simulate extreme sea level fluctuations during the floods in Saint Petersburg. To simulate extreme sea level fluctuations in the Baltic Sea, it is appropriate to use the BALT-P model which requires less input information. The analysis of simulation data for the considered cases reveals that the reason for the occurrence of the second flood maximum is the excitation of the wind-induced fundamental single-node seiche of the Baltic Sea.