Posters
Come meet the poster presenters to ask them questions and discuss their work
We would like to invite you to come and see the posters at our upcoming conference. The posters will showcase a diverse range of research topics, and will give delegates an opportunity to engage with the authors and learn more about their work. Whether you are a seasoned researcher or simply curious about the latest developments in your field, we believe that the posters will offer something of interest to everyone. So please join us at the conference and take advantage of this opportunity to learn and engage with your peers in industry and the academic community.
PO133: Scan geometry and pulse length effect on turbulence retrieval using a virtual vertically profiling Doppler Wind Lidar and a turbulence box generator
Clément Toupoint, Research & Application Engineer, Meteorology, Vaisala
Abstract
Reliable turbulence retrieval from Doppler Wind Lidars (DWLs) is critical for wind resource assessment and turbine monitoring. In vertically profiling configurations (DBS/VAD), the measurement volume of DWLs for one altitude is a truncated cone, determined by the zenith angle and pulse length. Two mechanisms dominate turbulence accuracy: along-beam averaging by the pulse, which filters eddies smaller than the pulse length, and the assumption of spatial homogeneity across the sensing volume during wind-field reconstruction. We present a quantitative study of how these factors jointly influence reconstructed turbulence statistics. Using PyConTurb -a synthetic 4D (x, y, z, t) turbulence box generator- coupled to a virtual lidar operating in DBS, we systematically map the influence of zenith angle and pulse length on the ratio of reconstructed to true wind speed variance, σlidar/σtrue. The analysis reveals a clear trade-off: smaller zenith angles reduce the measurement volume (strengthening the homogeneity assumption) but increase projection errors, whereas larger zenith angles reduce projection errors but expand the area over which homogeneity is assumed. Across the tested conditions at 100 m above ground level, the lidar measurement error is minimized near a zenith angle of about 30°, while σlidar/σtrue decreases monotonically with increasing pulse length, indicating stronger underestimation as along-beam averaging increases. The virtual lidar reproduces known DWL behaviors, supporting its use for design optimization, configuration selection, and uncertainty quantification. While demonstrated for horizontally isotropic turbulence over flat terrain, the approach could be extended to more complex flows and scan geometries.
