Analysis of the complex role of trees in street canyons using a large‐eddy simulation model

作者：Hynek Řezníček, Jan Geletič, Michal Belda, Luděk Beneš, Martin Bureš, Kryštof Eben, Vladimír Fuka, Pavel Krč, Petr Michálek, William R. Patiño, Jelena Radović, Matthias Sühring, Ondřej Vlček, Jaroslav Resler · 发表于：Quarterly Journal of the Royal Meteorological Society · 年份：2025 · DOI：10.1002/qj.4954 · 被引用次数：3 · 研究领域：Wind and Air Flow Studies、Urban Heat Island Mitigation、Plant Water Relations and Carbon Dynamics

Abstract While the positive effect of trees on thermal comfort is well‐established, particularly in urban street canyons, their impact on air quality remains questionable, especially in the case of pollutants emitted by heavy traffic at the pedestrian level. Complex microscale models of an urban boundary layer with a high spatial resolution (down to 1 m) enable a deeper understanding of most processes at street‐level scale and can simulate selected variables related to air quality and bio‐meteorology with high precision and fidelity. In this study, scenarios with different percentages of tree coverage of two streets were simulated under different atmospheric stratifications to investigate the problem. Real geography and quasi‐real meteorology were used as a background. Results of the Parallelized Large‐eddy Simulation Model (PALM) model simulations, which utilised a large‐eddy simulation (LES) core, showed the spatio‐temporal variability of the thermal comfort and dust concentration at the pedestrian level. The findings indicate that the effect of trees on the local microclimate is crucial and complex and cannot be omitted during the planning of urban mitigation measures. The study demonstrates a notable improvement in thermal comfort, with a significant decrease in the thermal index in shaded areas beneath trees during the hottest part of the day, as well as a cooling effect of urban greenery just after sunset. However, the analysis also revealed a significant downside: in n...