CALIBRATION & SIMULATION OF 2013 XAVER STORM SURGE IN THE UK WITH TELEMAC-2D NUMERICAL MODEL

Abstract

Safety is the overriding priority for EDF group and it is of utmost importance to characterize the natural hazards and extreme events that are a risk for nuclear power plants. After the Fukushima Daiichi Nuclear Disaster in 2011, EDF group continuously develop methodology and knowledge on natural hazards like inundation caused by extreme weather conditions. In Great Britain, 7 Nuclear Power Stations of EDF Energy are located near the coast, since the country has a long history of severe coastal flooding caused by storm surge, the threat is obvious. This study aims to establish a methodology based on public datasets to represent the mesoscale global storm tide activities in Great Britain caused by extreme winter storms or extratropical cyclones passing through the North Sea with a numerical approach. The reference event in this case is the Storm “Xaver” (5 – 6 December 2013) which is characterized by a west-to-east path from the North Atlantic to Scandinavia and coincided with large astronomic tides. This study follows the progress of previous works on the open source numerical hydrodynamic solver system TELEMAC-2D to simulate storm surge in Great Britain. It provides an optimized mesh surrounding Great Britain, calibration of initial & boundary conditions (tide and weathers) as well as calculation settings by conducting various sensitivity tests. Tide conditions are provided by TPXO, sea level pressure and 10-meter wind field are built using Weather Research and Forecasting model (WRF) validated against ERA5 allowing a 10 km x 10 km and a 15 minutes input weather resolution. The final results of the model are greatly improved in term of both values and tendencies with an RMSE of about 15 to 20 cm along the Great Britain tide gauges. However, in order to present more accurate results, more work should be made in term of validation case of other extreme events in the Great Britain and models with smaller scales could also be established for obtaining better result for specific stations.