Wessels’ wind measurement corrections : applied to rigs on the North Sea

Ministry of Infrastructure and Water Management, Royal Netherlands Meteorological Institute, T.H. Joosten and A. Stepek
De Bilt : KNMI
2019

In this report, wind measurements of the platform AWG1 are analyzed and compared to good measurement sites (MMIJ, OWEZ). The measurements of AWG1 initially do not comply with WMO/ICAO accuracy requirements. Correction formulae derived by Wessels are applied to the measurements. [7] They take into account the presence of a vent stack which supports the wind measuring devices. Furthermore, optimal schemes to combine the different measurement sets into one set are analyzed. The aim of all of the above was to improve the measurements. Before correcting, the wind direction dependent biases of the AWG1 2012 and 2013 measurements w.r.t. KNW-atlas data are smaller than 1.8 m/s and 21 degrees. The corrected values for the wind speed all have a bias smaller than 1.3 m/s. For the wind direction, a bias of at most 13 degrees is found when the wake cause by the vent stack comes close to the wind vane. While the biases of the measurements are reduced significantly by applying Wessels’ corrections and the introduced schemes, they still do not comply with WMO/ICAO standards.

39 p.
Fig., tab.
(Internal report ; 2019-02)
With ref.
KNMIAUT2019