On the mechanisms of the Neva floods formation
The comparative contribution of sea level oscillations of different time scales (interannual, seasonal, synoptical and mesoscale) in the formation of Neva floods is estimated. It is established that conventional identification of Neva flood waves as long gravity waves is not valid. Comparison of estimated characteristics of Neva floods with theoretical dispersion relations of various types of long waves is carried out. This comparison and also the results of analysis of meteorological information as well as earlier numerical experiments with the Baltic Sea hydrodynamic model shows that Neva flood waves may be identified as forced baroclinic topographic waves generated as the result of resonance between anemobarical forces in atmospheric cyclones and eigenmodes of Open Baltic Sea - Gulf of Finland system.