Historical storm surges in the German Bight

Elke Meyer1, Ralf Weisse1, Birger Tinz2 and Thomas Möller2, (1)Helmholtz-Zentrum Geesthacht Centre for Materials and Coastal Research, Institute of Coastal Research, Geesthacht, Germany, (2)Deutscher Wetterdienst (DWD), Hamburg, Germany
In the last century several strong storm surges are occurred in the German Bight. Extremely high water levels are caused by the coincidence of high astronomical tides and high surge levels caused by strong winds. Especially in the first decades of the last century, only limited atmospheric data is available. Long-term atmospheric reanalyses enable the simulation of individual storm surges. In addition, historical data from daily weather maps by the Deutscher Wetterdienst (DWD, German Meteorological Service) were digitized, isobaric maps drawn and digitized again. The latter comprise additional data that were so far not available for assimilation in the reanalysis. From the digitized isobaric maps the geostrophic wind as well with a simple boundary-layer parameterization according to Hasse (1974) marine near surface wind speeds were calculated. These wind fields and the wind fields from long-term reanalysis are used as forcing data for the hydrodynamic model TRIM-NP to calculate the water levels for the German Bight. We show examples of historical storm surges, how different methods work and where there is room for improvement.