Atmospheric stability and wind profile climatology over the North Sea: Case study at Egmond aan Zee

The statistics of atmospheric stability and non-dimensional wind profiles are studied using the standard surface-layer theory at Egmond aan Zee in the North Sea. Measurements at 21, 70 and 116 m are used to validate the theoretical profiles. Charnock’s relation is used to estimate the sea surface roughness. Bulk Richardson number is used to estimate the Obukhov length. The measured sea water temperature has a positive bias of 0.82?C resulting in the dominance of unstable conditions and a poor agreement of the theoretical wind profiles with the measurements. The conditions at Egmond aan Zee are dominated by unstable and neutral stabilities. The theoretical wind profiles agree very well with the measurements in the unstable and neutral conditions. In stable conditions, the wind profiles are over-predicted significantly as the height increases. The scaling of the wind profile with respect to the boundary layer height is necessary under stable conditions and the addition of another length scale parameter is preferred.
Aerodynamics, Wind Energy & Propulsion
Aerospace Engineering