For this the NOAA/NCEP reanalysis data was used.

In addition the driving forces of the storm in the North East Atlantic needed to be represented. Tidal data was obtained from the MIKE 21 toolbox to allow the flow model to be adequately resolved. The coupled model developed makes use of the Spectral Wave and Hydrodynamic modules of the MIKE by DHI software and uses freely available data sources as inputs.įor this regionally focused modeling study, bathymetry data has been sourced from the GEBCO 08 Grid bathymetry data set which provides a 30 arc-second grid of the entire globe. With this in mind, DHI have developed a demonstration model of this event to show how the Flexible Mesh series of models allows you to take large scale North East Atlantic basin driving forces to understand the impact at a local scale. With increasing emphasis from operating authorities being placed on beach management of such natural defences, it is important to understand the driving conditions in an event such as this to plan effective management. Greenwood (1984) noted that reflective beaches, which are already prone to sub-harmonic edge waves, can interact with longer period swell waves leading to an amplification of wave run up, a mechanism which leads to higher than anticipated overtopping and overwashing of the crest with consequent implications for barrier stability and hinterland flooding. It is important to note that many of the beaches along the south coast are gravel/shingle dominated barriers which are typically considered reflective in morphological classifications (Short 1979). Whilst this is not unusual in itself (beaches along the south coast have historically been subject to similar storms), the combination with high water of these small wave height, long period waves led to a series of flooding “near misses” along the South Coast as swell waves led to damage and overtopping of some defences including natural barrier beaches. In February this year (2011) a large storm in the North Atlantic caused swell waves with periods of 20-25 seconds to propagate into the English Channel. Example MIKE 21 Coupled Model to investigate swell wave propagation in the English Channel

Mike 21 wave model examples