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Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.

Wang Y, Bakker F, de Groot R, Wörtche H, Leemans R - Environ Monit Assess (2015)

Bottom Line: The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions.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.

View Article: PubMed Central - PubMed

Affiliation: Environmental System Analysis group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands. feifeinetherland@hotmail.com.

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.

No MeSH data available.


Related in: MedlinePlus

The location of the observation sites in the city of Assen, The Netherlands. Source: Google Earth (left) and screenshot of OpenStreetMap (OSM; right)
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Fig1: The location of the observation sites in the city of Assen, The Netherlands. Source: Google Earth (left) and screenshot of OpenStreetMap (OSM; right)

Mentions: Assen, the capital of the Drenthe Province, is located in the north-western part of The Netherlands. It mainly enjoys a typical oceanic climate with mild winters and cool summers. May and June (spring) are the sunniest months of the year, and July and August (summer) are the warmest months. In the autumn, the weather becomes cooler, cloudy, and rainy, with frequent winds, while the sunshine time is only around 2 h each day. During this period, microclimate regulation by UGI is less important with less shade and evapotranspiration and does not play an essential role in human thermal comfort. Therefore, our study was targeting on spring and summer, and the measurements were carried out during the growing seasons, which were from leafless season (April and May) to full leaf season (June to August). We have conducted field measurements at five sites in a small urban area (approximately 3600 m2, latitude of 53° 0′ 0″ N, longitude of 6° 55′ 00″ E) in Assen (Fig. 1). The microclimatic data obtained from the study site’s open space (site A) supplied the reference data to compare with the other observation sites. This particular site was selected because of its best sunlight exposure, which minimized the influence from the surroundings. Different types of UGI were included in the study area: site B was surrounded by a group of trees (situated in a grove), site C was beneath a single deciduous tree, site D was located at the street side to observe the impact of street trees, and site E was placed adjacent to the building to determine the effect of the building’s façade on ambient microclimate.Fig. 1


Effects of urban green infrastructure (UGI) on local outdoor microclimate during the growing season.

Wang Y, Bakker F, de Groot R, Wörtche H, Leemans R - Environ Monit Assess (2015)

The location of the observation sites in the city of Assen, The Netherlands. Source: Google Earth (left) and screenshot of OpenStreetMap (OSM; right)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4636989&req=5

Fig1: The location of the observation sites in the city of Assen, The Netherlands. Source: Google Earth (left) and screenshot of OpenStreetMap (OSM; right)
Mentions: Assen, the capital of the Drenthe Province, is located in the north-western part of The Netherlands. It mainly enjoys a typical oceanic climate with mild winters and cool summers. May and June (spring) are the sunniest months of the year, and July and August (summer) are the warmest months. In the autumn, the weather becomes cooler, cloudy, and rainy, with frequent winds, while the sunshine time is only around 2 h each day. During this period, microclimate regulation by UGI is less important with less shade and evapotranspiration and does not play an essential role in human thermal comfort. Therefore, our study was targeting on spring and summer, and the measurements were carried out during the growing seasons, which were from leafless season (April and May) to full leaf season (June to August). We have conducted field measurements at five sites in a small urban area (approximately 3600 m2, latitude of 53° 0′ 0″ N, longitude of 6° 55′ 00″ E) in Assen (Fig. 1). The microclimatic data obtained from the study site’s open space (site A) supplied the reference data to compare with the other observation sites. This particular site was selected because of its best sunlight exposure, which minimized the influence from the surroundings. Different types of UGI were included in the study area: site B was surrounded by a group of trees (situated in a grove), site C was beneath a single deciduous tree, site D was located at the street side to observe the impact of street trees, and site E was placed adjacent to the building to determine the effect of the building’s façade on ambient microclimate.Fig. 1

Bottom Line: The results showed that groves with high tree density (site B) have the strongest effect on microclimate conditions.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.

View Article: PubMed Central - PubMed

Affiliation: Environmental System Analysis group, Wageningen University, P.O. Box 47, 6700 AA, Wageningen, The Netherlands. feifeinetherland@hotmail.com.

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.

No MeSH data available.


Related in: MedlinePlus