The Reasons for Increase in the Neva River Flood Frequency in Recent Decades

E. A. Zakharchuk, V. N. Sukhachev, and N. A. Tikhonova

Basing on the statistical analysis of hydrometeorological data, the reasons are studied for the interannual variations of the frequency of dangerous rises in the Baltic Sea level in the east of the Gulf of Finland. The obtained results do not corroborate the hypothesis that the interannual variability of the characteristics of atmospheric cyclones affects increase in the frequency of floods in the Neva River estuary in recent decades. Contrary to the results of the cross-correlation analysis of the number of floods and characteristics of atmospheric cyclones for some areas of the Baltic Sea, significant correlation is observed between the number of dangerous sea level rises in the east of the Gulf of Finland and the variations of its baroclinic conditions. This result is interpreted taking account of the peculiarities of the dynamics of baroclinic topographic waves that exert significant influence on the formation of dangerous sea level rises in the east of the Gulf of Finland.

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