Momentum flux measurements are important for describing the wind profile in the atmospheric boundary layer, modeling the atmospheric flow over water, the accounting of exchange processes between air and sea, etc. It is also directly related to the friction velocity, which is a velocity scale required for wind engineering. Estimations of friction velocity over the sea can be performed by combining wind speed measurements, a sea roughness length formulation and the surface-layer wind profile, i.e. a bulk-derived method. This method was tested in Peña et al. (2008) by comparison with direct turbulence measurements from a sonic anemometer, showing high agreement. In this study, a conical scanning lidar is used to derive the momentum flux, which compares well to the estimations from the bulk-derived method, but it also shows a filtering effect due to the large spatial-averaging volume of the lidar. The spectral model by Mann (1994) is then used to numerically estimate the filtering effect of the lidar and the predictions have a good agreement with the observations for near-neutral conditions over the North Sea at the Horns Rev wind farm.
|Publication status||Published - 2009|
|Event||European Offshore Wind 2009 - Stockholm, Sweden|
Duration: 14 Sep 2009 → 16 Sep 2009
|Conference||European Offshore Wind 2009|
|Period||14/09/2009 → 16/09/2009|
- Wind energy