Cristin-resultat-ID: 1095262
Sist endret: 19. november 2015, 14:47
Resultat
Poster
2013

Coupled atmosphere - ocean wave modelling for wind power applications

Bidragsytere:
  • Alastair David Jenkins
  • Idar Barstad
  • Torge Lorenz
  • Alok Kumar Gupta og
  • Angus Graham

Presentasjon

Navn på arrangementet: EWEA Offshore 2013
Sted: Frankfurt
Dato fra: 19. november 2013
Dato til: 21. november 2013

Arrangør:

Arrangørnavn: European Wind Energy Association

Om resultatet

Poster
Publiseringsår: 2013

Beskrivelse Beskrivelse

Tittel

Coupled atmosphere - ocean wave modelling for wind power applications

Sammendrag

COUPLED ATMOSPHERE - OCEAN WAVE MODELLING FOR WIND POWER APPLICATIONS ---Introduction--- Marine wind power production facilities are subjected to the effects of ocean waves, directly as well as indirectly. Waves act as roughness elements, acting on the wind speed and turbulence profile. Waves also affect offshore structures directly, and via their influence on ocean currents and sediment transport. The effect of waves on the atmospheric boundary layer may be important for wind resource assessment, and we should be able to estimate this effect using a coupled atmosphere - ocean wave model system. ---Approach--- Our approach involves coupling together two numerical models: a mesoscale atmosphere model - the Weather Research and Forecasting Model (WRF), and a spectral wave model (WAM) which employs radiative transfer equations on wave spectral components of different wave frequencies and directions. The two models are coupled together using the Model Coupling Environmental Library (MCEL), which allows for exchange of dynamical variables and their interpolation from and to differing spatial model grids and time-stepping schemes. ------ The atmosphere model WRF is run on a polar stereographic domain of 9 km grid spacing, using a Mellor-Yamada-Janjic turbulent planetary boundary layer scheme, and the wave model is run on a 0.08 degree latitude x 0.16 degree longitude geographical grid. Each model domain has approximately 500 x 500 grid cells. The models are run simultaneously, and exchange of dynamical variables via MCEL is performed every 60 model minutes. The wave model WAM is driven by the computed wind speed at 10 metres height, and computes the wave-induced component of the air-sea momentum flux, as a fraction of the total air-sea momentum flux, which is then fed back to the atmosphere model. The surface boundary-layer scheme in WRF has been modified to compute the consequent modification of the surface roughness length (or the change in the Charnock parameter relating the roughness length to the friction velocity). Comparision of the results of a 4-week model run with radiosonde wind observations in the lowest 1000 metres of the amosphere, and with QuikSCAT satellite radar observations of sea surface winds, indicate that the coupled model system may reduce the model bias and root-mean square error, particularly over the North Sea, when compared with model results from a mesoscale atmospheric model simulation alone. ---Conclusion--- The results of the coupled atmosphere-wave model simulations are promising, and may improve wind speed estimates in the boundary layer, at least in the North Sea. It is possible to use different model domains and grid spacings for the two models. Ongoing work involves refining the model system by nesting down to 1-2 km grid resolution, and extending the model run period to at least 12 months to encompass seasonal variations.

Bidragsytere

Alastair D. Jenkins

Bidragsyterens navn vises på dette resultatet som Alastair David Jenkins
  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS

Idar Barstad

  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS

Torge Lorenz

  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS

Alok Kumar Gupta

  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS

Angus Graham

  • Tilknyttet:
    Forfatter
    ved NORCE Energi og teknologi ved NORCE Norwegian Research Centre AS
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