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| Titel |
Sea state modelling from the global ocean to the beach and coupling with coastal circulations |
| VerfasserIn |
Fabrice Ardhuin, Aron Roland, Jean-François Filipot, Fabien Leckler |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250049459
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| Zusammenfassung |
| Today’s numerical wave models are least accurate in swell-dominated contitions and in
coastal environments, in particular in enclosed basins. Recent development have brought
considerable improvements in swell-dominated conditions thanks to a better understanding of
swell energy dissipation (Ardhuin et al. Geophys. Res. Lett. 2009) and work is ongoing to
also correct biases on the spatial distribution of swell fields (Delpey et al., J. Geophys. Res.
2010). The coastal areas present several challenges in terms of forcing fields (winds and
currents), numerical constraints (high resolution needed at the shoreline) and still poorly
represented physical processes (wave breaking, bottom friction). We present here ongoing
work based on unstructured grid modelling of coastal environments on the French coasts
using the future version (4.xx) of the WAVEWATCH III code to be released in 2011 or
2012 by NCEP, and jointly developed at Ifremer and T.U. Darmstadt as particular
as part of a large U.S. National Ocean Partnership Program and E.U. FP7-ERC
project "IOWAGA" (http://wwz.ifremer.fr/iowaga). The model results are particularly
investigated in terms of important variables for wave-current coupling. These include the
surface Stokes drift which is found to be very sensitive on the shape of the wave
spectrum at high frequencies (Ardhuin et al., J. Phys. Oceanogr. 2009), and which can
be estimated from wave spectra measured by ocean buoys. We also investigate in
details the quality of modelled wave spectra in intermediate water depths such as the
English Channel, Southern North Sea and U.S. East Coast where details of both
bottom friction and wave breaking paramaterizations can have a strong influence
on the model solutions. It is found that a movable-bed bottom friction that uses
known sediment characteristics can provide accurate results when combined with
physically-based parameterizations of wave breaking. Other parameters needed for
wave-current coupling are still uncertain, such as the underwater roughness length (e.g.
Gemmrich et al., J. Phys. Oceanogr. 2009; Rascle and Ardhuin J. Geophys. Res. 2009)
which points to future investigations of processes at the air-sea and water-sediment
interfaces. |
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