Analysis of the Turbulence Intensity at Skipheia Measurement Station
Abstract
Two years of data from the coastal measurement station at Skipheia in Norway have been analysed to characterise the atmospheric turbulence intensity (TI) in the wind. In addition to consider all data at 70 meters in one, two direction sectors have been chosen to represent onshore and offshore conditions. The turbulence intensity has been investigated in terms of atmospheric stability, seasonal variations, diurnal patterns and measurement height. Additionally, the results are compared to predictions for TI given by the International Electrotechnical Commission (IEC) through the Normal Turbulence Model (NTM). Previous work has found NTM to be incompatible with coastal and offshore measurements, and this is also the case in the current study. For Skipheia, TI in the offshore sector was observed to be slightly less than in the onshore sector, and the diurnal TI pattern more pronounced in the latter. In addition, differences in TI between the two sectors are more distinct in summer than in winter. This work is hoped to contribute to a better understanding of coastal and offshore wind regimes, and for further research of the conditions at Skipheia.