Journal cover Journal topic
Annales Geophysicae An open-access journal of the European Geosciences Union
Ann. Geophys., 28, 1043-1052, 2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.
03 May 2010
The influence of humidity fluxes on offshore wind speed profiles
R. J. Barthelmie1,2, A. M. Sempreviva2,3, and S. C. Pryor1,2 1Atmospheric Science Program, College of Arts and Sciences, Indiana University, Bloomington, IN 47405, USA
2Wind Energy Division, Risø DTU National Laboratory for Sustainable Energy, 4000 Roskilde, Denmark
3Institute of Atmospheric Sciences and Climate, Institute of Atmospheric Sciences and Climate, CNR, I 88046 Lamezia Terme, Italy
Abstract. Wind energy developments offshore focus on larger turbines to keep the relative cost of the foundation per MW of installed capacity low. Hence typical wind turbine hub-heights are extending to 100 m and potentially beyond. However, measurements to these heights are not usually available, requiring extrapolation from lower measurements. With humid conditions and low mechanical turbulence offshore, deviations from the traditional logarithmic wind speed profile become significant and stability corrections are required. This research focuses on quantifying the effect of humidity fluxes on stability corrected wind speed profiles. The effect on wind speed profiles is found to be important in stable conditions where including humidity fluxes forces conditions towards neutral. Our results show that excluding humidity fluxes leads to average predicted wind speeds at 150 m from 10 m which are up to 4% higher than if humidity fluxes are included, and the results are not very sensitive to the method selected to estimate humidity fluxes.

Citation: Barthelmie, R. J., Sempreviva, A. M., and Pryor, S. C.: The influence of humidity fluxes on offshore wind speed profiles, Ann. Geophys., 28, 1043-1052, doi:10.5194/angeo-28-1043-2010, 2010.
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