| Popis: |
As part of the Dutch Offshore Wind Atlas (DOWA) project, analyses were performed on offshore wind measurements to provide enhanced characterisation of the North Sea wind climate. Of particular interest was the spatiotemporal behaviour of the offshore low-level jet (LLJ) – an anomalous wind event that can significantly impact both wind turbine power performance and loading. LLJs are characterised by a maximum in the vertical wind speed profile relatively close to the surface. LLJ frequency, vertical wind profile characteristics, and onset mechanisms have been extensively studied onshore. However, accurate measurement of the offshore wind environment at high altitudes (i.e. above typical mast heights [~100 m]) has historically been limited. Therefore, less is known regarding the behaviour of the offshore LLJ. Recent emphasis on offshore wind measurement by the Dutch Ministry of Economic Affairs has prompted the installation of high-quality anemometry on platforms distributed throughout the North Sea. Including both meteorological masts and light detection and ranging (lidar) units, these measurement systems enable accurate measurement of atmospheric boundary layer (ABL) winds at high altitudes, thereby increasing researcher ability to study anomalous wind behaviour offshore. Within this study, wind data from seven different North Sea measurement platforms – including several located within wind farm zones – were analysed to investigate North Sea LLJ behaviour |
