Scanning Doppler lidar at Cabauw: study of the convective boundary layer in the summer of 2022

A scanning Doppler lidar, the  Windcube200S (Vaisala/Leosphere), has been operating at our research site Cabauw since April 2021, to provide detailed measurements of the wind field, aerosols and clouds, in the framework of Ruisdael Observatory [1]. First measurements mainly focused on operational wind profiling (based on DBS scans). The phenomenon of the triplet storm in February 2022 (Dudley, Eunice, Franklin) was nicely captured by the Doppler lidar. Synergy with a Doppler cloud radar was demonstrated, providing wind profiles up and within clouds [2]. Doppler lidar wind profiles can also be combined with the in situ wind measurements in the tall mast up to 200m, for instance for low-level jet studies and climatology.

In this presentation we focus on a measurement campaign we performed in the summer of 2022 (June 21 to August 21), which was aimed to study the convective boundary layer. For this the Doppler lidar continuously performed vertical stare scans with an accumulation time of 1 s, interrupted each hour with 10 minutes of wind profiling (DBS scans) and a low-elevation azimuth scan (PPI) of 3 minutes. The vertical stare data nicely show the up- and downdrafts, together with the formation and presence of (shallow cumulus) clouds. We show a direct comparison between the vertical velocity data and high resolution large eddy simulations and numerical weather prediction model simulations, and discuss the possibilities in model development and validation. 

From the vertical stare data also turbulence characteristics, such as the variance and dissipation rate, can be extracted. From the variance the mixing height can be derived. We will apply a retrieval method of the vertical wind speed variance and dissipation rate including the effect of probe volume of the Doppler lidar [3], which we will validate by sonic measurements in the tall mast.

[1] https://ruisdael-observatory.nl/

[2] José Dias Neto, Louise Nuijens, Christine Unal, and Steven Knoop, Combined wind lidar and cloud radar for high-resolution wind profiling, Earth Syst. Sci. Data 15, 769, 2023, https://doi.org/10.5194/essd-15-769-2023

[3] Banakh, Smalikho, Falits, Sherstobitov, Estimating the Parameters of Wind Turbulence from Spectra of Radial Velocity Measured by a Pulsed Doppler Lidar, Remote Sens. 13, 2071, 2021, https://doi.org/10.3390/rs13112071