Winter Storm Surge Event Long-Term Variability in the North Atlantic

Abstract

Changes in storm surge events are investigated using the Event CHARacterization method, which identifies and quantifies the various dynamical structures of a typical storm surge event. This method was applied yearly, using a 20 year sliding window, to a set of 41 long-term tide gauges in the North Atlantic. Storm surge events were investigated on the basis of four key parameters: the amplitude and duration of two structures related to atmospheric pressure (Gaussian structure) and wind stress (Laplace structure). The analysis reveals large changes in 71% of the tide gauges, located in the eastern North Sea, the Baltic Sea, and in specific regions of North America. Changes are more important for the duration $\left(\pm 16\%\right)$ of the events than for the amplitude $\left(\pm 7\%\right)$. In Europe, the pressure-induced structure (Gaussian) is more affected by changes than the wind-stress-induced structure (Laplace). In addition, the changes in North America show patterns with significant linear trends that lacked discernible geographical coherence, while in Europe, the changes exhibit cyclic patterns with more obvious geographical coherence.