A Doppler Wind-LiDAR (WindCube WLS8-8 (Toch, 2013) from the manufacturer Leosphere, France) was installed at the island Heligoland (54° 10' 38,12"N,7° 53'30,90" E installed almost at sea level ) in the German Bight, North Sea, and operated continuously for a period of an entire year. For system specifications please refer to Toch (2013). The Wind-LiDAR was installed on the site of the Alfred-Wegener-Institute near the port of Heligoland. The terrain is flat for winds from south, south-west and south-east without obstacles that could affect the wind profile above 40 m. However, for north-west and north directions a plateau level of about 50 m exists, which could influence the wind at the lowest measuring heights. The Wind-LiDAR provided the vertical profiles of the wind speed components, measured by means of the Doppler Beam Swinging technique. Four lines of sight are sequentially scanned by a 1.54 µm pulsed fiber laser to perform the geometrical computation of the 3D wind vector components. From the raw data, the average horizontal wind speed and wind direction is calculated routinely for intervals of 10 min. The Wind-LiDAR was in operation from 24 March2017to 10 April2018 and continuously collected profiles of wind speed and wind direction at 25 altitudes (40 m to 500 m, with a vertical resolution of 10 m up to 100 m, 20 m up to 400 m, and 50 m up to 500 m). The data availability ranged from 95.3% at 40m to 70.4% at 500m for the entire measurement campaign. Data gaps are mainly caused by low clouds and fog, which cannot be penetrated by the laser pulses. During the measurements, the system was oriented with a heading offset of -17° in relation to geographical North. Thus, all direction values in the dataset must be corrected by -17° in order to obtain wind directions in a North-oriented coordinate system.

Acknowledgements: The LiDAR observations have been funded by the projects WIPAFF and AVATAR, German Federal Ministry for Economic Affairs and Energy, grant numbers 0325783B / 20Y1501F. The installation and remote supervision of the wind lidar have been performed by Christian Krüger of UL International. The authors would like to thank Heino Peters, Andreas Schmidt, Helgo Denker, Eva-Maria Brodte and Karen Wiltshire for the opportunity to install the Wind-LiDAR at the site of the Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research.