News 28.3.2022

Windy over Helsinki? Scientist uncovered direction-dependent wind patterns with 3D scanning lidar

Scientists uncovered direction-dependent wind patterns over the coastal urban environment of Helsinki, Finland. They used a novel volume wind processing approach to retrieve the horizontal wind information on a 3D spatial grid from observations of a scanning Doppler wind lidar.
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When comparing the observations by the Doppler wind lidar, Vaisala Windcube 400s, to three operational models at the Finnish Meteorological Insititute (LAPS, LEPS and MEPS), the interesting channelling effect of the wind flow was absent. This stressed out the need of performing high spatial and temporal wind observations over morphologically complex areas.

The Doppler lidar observations showed that the strongest winds, on average, prevail during winter and the weakest winds are during summer. The long-term comparison of the mean profiles of the modelled wind are in good agreement with the observations. The study showed that the selected models exhibit different strengths and weaknesses depending on the atmospheric conditions but no significant diurnal variation in performance was observed.

Accurate wind forecasts in urban areas are essential for predicting the heat island effect (UHI), air pollution, energy demand and safety of drone-related operations. Yet, forecasting the wind in an urban environment can be challenging due to the complexity of the city morphology which varies from street to street altering the wind flow.

Further information

Maria Filioglou, Finnish Meteorological Institute,

Filioglou, M., Preissler, J., Troiville, A., Thobois, L., Vakkari, V., Auvinen, M., Fortelius, C., Gregow, E., Hämäläinen, K., Hellsten, A., Järvi, L., O'Connor, E., Schönach, D., & Hirsikko, A. (2022). Evaluating modelled winds over an urban area using ground-based Doppler lidar observations. Meteorological Applications, 29( 2), e2052.

Scientific article is available on Meteorological Applications.