Evaluation of a wind-farm parametrization in a regional climate model using large eddy simulations
Chatterjee, F.; Allaerts, D.; Blahak, U.; Meyers, J.; van Lipzig, N.P.M. (2016). Evaluation of a wind-farm parametrization in a regional climate model using large eddy simulations. Q. J. R. Meteorol. Soc. 142(701): 3152-3161. https://dx.doi.org/10.1002/qj.2896
In: Quarterly Journal of the Royal Meteorological Society. Royal Meteorological Society: Bracknell, Berks. ISSN 0035-9009; e-ISSN 1477-870X, more
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wind-farm parametrization; ideal simulation; COSMO-CLM; LES; constantthrust wind-farm parametrization; Channel flow; Ekman flow |
| Authors | | Top |
- Chatterjee, F., more
- Allaerts, D., more
- Blahak, U.
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- Meyers, J., more
- van Lipzig, N.P.M.
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| Abstract |
The increasing number of wind farms in the North Sea planned for 2020 is likely to affect the local, regional and perhaps global climate. To this effect, it is crucial to be able to model wind farms adequately on the regional scale. Wind farms have previously been implemented in regional climate models. However, such models have rarely been thoroughly evaluated, due to a lack of observation.In this study, an idealized version of the COSMO-CLM regional climate model is used in order to evaluate a constant thrust version of the Fitch wind-farm parametrization using large eddy simulations (LES). As a benchmark for the COSMO-CLM and LES comparison, a channel flow without wind farms is first evaluated. COSMO-CLM is able to reproduce this channel flow with a root-mean-square error (RMSE) of 0.6 m s–1 (4%) and an Ekman flow with an RMSE of 0.05 m s–1 (2%). Next, the wind-farm parametrization is implemented and evaluated. The wind-farm parametrization yields a RMSE of 4 m s–1(12%) in wind speed for the channel flow and an RMSE of 0.2 m s–1(3%) for the Ekman flow. Based on LES output, a parameter was introduced to correct for the use of the grid-box averaged velocity to calculate the thrust force in the wind-farm parametrization instead of the disc-averaged wind speed. This correction had little impact on the RMSE, showing that the use of the grid-box velocity in the wind-farm parametrization is adequate. |
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