title: Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.
abstract: This study analyzed how the variations of plant area index (PAI) and weather conditions alter the influence of urban green infrastructure (UGI) on microclimate. To observe how diverse UGIs affect the ambient microclimate through the seasons, microclimatic data were measured during the growing season at five sites in a local urban area in The Netherlands. Site A was located in an open space; sites B, C, and D were covered by different types and configurations of green infrastructure (grove, a single deciduous tree, and street trees, respectively); and site E was adjacent to buildings to study the effects of their façades on microclimate. Hemispherical photography and globe thermometers were used to quantify PAI and thermal comfort at both shaded and unshaded locations. The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions. Monthly variations in the differences of mean radiant temperature (∆Tmrt) between shaded and unshaded areas followed the same pattern as the PAI. Linear regression showed a significant positive correlation between PAI and ∆Tmrt. The difference of daily average air temperature (∆T a ) between shaded and unshaded areas was also positively correlated to PAI, but with a slope coefficient below the measurement accuracy (±0.5 °C). This study showed that weather conditions can significantly impact the effectiveness of UGI in regulating microclimate. The results of this study can support the development of appropriate UGI measures to enhance thermal comfort in urban areas.
authors.affiliation: Environmental System Analysis group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands. feifeinetherland@hotmail.com.|INCAS³, P.O. Box 797, 9400 AT, Assen, The Netherlands. feifeinetherland@hotmail.com.
authors.forename: Yafei
authors.initials: Y
authors.lastname: Wang
authors.affiliation: INCAS³, P.O. Box 797, 9400 AT, Assen, The Netherlands.
authors.forename: Frank
authors.initials: F
authors.lastname: Bakker
authors.affiliation: Environmental System Analysis group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
authors.forename: Rudolf
authors.initials: R
authors.lastname: de Groot
authors.affiliation: INCAS³, P.O. Box 797, 9400 AT, Assen, The Netherlands.
authors.forename: Heinrich
authors.initials: H
authors.lastname: Wörtche
authors.affiliation: Environmental System Analysis group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands.
authors.forename: Rik
authors.initials: R
authors.lastname: Leemans
mesh_terms: D000383:Agriculture; D002947:Cities; D004784:Environmental Monitoring; D008834:Microclimate; D009426:Netherlands; D010944:Plants; D012621:Seasons; D013696:Temperature; D014197:Trees; D014887:Weather
keywords: Field measurements; Green infrastructure; Outdoor thermal comfort; Plant area index; Urban microclimate