Ground-Based Measurements of Wind and Turbulence at Bucharest-Magurele: First Results

Doppler wind lidar measurements were used for the first time in Romania to analyse the wind and turbulence statistics for a peri-urban site located at Magurele, southwest of Bucharest. Vertical and scanning measurements between December 2019 and November 2021 were processed using an existing toolbox. The statistics over the two-year period were performed on seasonal and diurnal cycle bases. The analyses showed a diurnal cycle for the horizontal wind speed, with lower values during daytime. In the upper part of the planetary boundary layer (PBL), the wind speed is lowest during the day and highest at night (near surface, the behaviour is reversed). The diurnal cycle has variations during the year (from approximately 500 m during midnight winter to approximately 1250 m during summer noon). The wind direction during autumn shows similarities with the summer season, with prevailing directions from east and northeast. The winter season is characterised by westerly winds. The most variable diurnal wind direction is observed during summer, with nighttime westerly winds and changing directions (from northeast to west) during daytime. The ERA5 reanalysis shows similar patterns for wind speed with Doppler wind lidar (slightly underestimated) and direction. The planetary boundary layer classes over the altitude region analysed shows the predominant convection during daytime and non-turbulent behaviour during nighttime. To a lesser extent, the intermittent turbulent class is observed during the growth and the decay of the mixing layer.

Automated summary

For the first time in Romania, Doppler wind lidar measurements were used to analyze wind and turbulence statistics at a peri-urban site in Magurele, southwest of Bucharest. Vertical and scanning measurements from December 2019 to November 2021 were processed, and statistics were performed based on seasonal and diurnal cycles. The results showed variations in diurnal wind speed and direction, with lower speed during the day and higher at night. The ERA5 reanalysis exhibited similar patterns to the Doppler wind lidar measurements, albeit slightly underestimated in terms of wind speed.