The Impact of Offshore Wind Farms on Sea State Demonstrated by Airborne LiDAR Measurements

The increasing number of wind farms installed in the North Sea has an impact on the downstream wind speed. This has been hypothesized as well for sea state properties. Wave effects can be expected in particular in fetch-limited conditions with offshore wind directions. With systematic flights deploying an airborne laser scanner, these impacts are shown directly for the first time. The flights were conducted perpendicular to the main wind direction upstream and downstream of the cluster of the offshore wind parks Amrumbank West, Nordsee Ost, and Meerwind Sud/Ost. The flight legs covered the area potentially influenced by the wind parks and the undisturbed area next to the wind parks. The analysis of the spectral energy distribution shows a re-distribution of the wave energy in the downstream area with enhanced energy at smaller wavelengths. The effect is still clearly visible at a distance of 55 km. As the sea surface constitutes the link between the atmosphere and the ocean, it is very likely that wind parks modify the properties of the water column as well.

Automated summary

The installation of wind farms in the North Sea has been shown to affect downstream wind speed and wave properties. Using airborne laser scanner flights, it was demonstrated that wind parks redistribute wave energy in the downstream area, enhancing energy at smaller wavelengths. This suggests that wind parks may modify the properties of the water column as well, as the sea surface serves as a link between the atmosphere and the ocean.