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- Green space influence on thermal comfort contrasting approaches in the assessment of conditions in Bragança (Portugal)Publication . Gonçalves, Artur; Ribeiro, A.C.; Nunes, Luís; Maia, Filipe; Feliciano, ManuelGreen Spaces are regarded as elements that can help to provide thermal comfort inside cities. To evaluate this influence both climate and personal variables must be investigated and evaluated taking into account different spatial layouts. Trying to address this complex reality, two different approaches were developed, using green spaces at the city of Bragança (Portugal) as case studies: green spaces surveys, addressing users, and structured experiments, controlling both individual and climatic variables. Field surveys proven to identify a narrow range of thermal sensations, thus limiting the analysis. Data from a structured experiment, conducted in early fall conditions, show the influence of different green space locations on both meteorological variables and thermal sensations. Amongst the evaluated variables, global radiation proves to be the most relevant variable influencing the perceived thermal sensations.
- Influence of green spaces on outdoors thermal comfort-structured experiment in a Mediterranean climatePublication . Gonçalves, Artur; Ribeiro, A.C.; Maia, Filipe; Nunes, Luís; Feliciano, ManuelAs a growing part of the global population lives in cities, green spaces are an essential asset for improving quality of life. This study aims to address the role of green spaces in providing favorable thermal comfort conditions for the use of outdoor spaces. The research methodology consisted of a structured experiment where a defined set of individuals from different age groups was exposed to differentiated microclimate conditions. Four nearby locations were considered, ranging from a stone-paved surface without shade to high tree canopy coverage over grass. This experiment took place in three different days in summer and early autumn conditions, with a total of 432 questionnaires. Results show a wide range of thermal sensations found during this experiment, while more favorable thermal sensations were found in shaded locations. To investigate the role of prevailing meteorological and personal conditions on thermal sensations, multinomial logistic regression analysis was applied. Results show the influence of air temperature, global radiation, wind speed, and interviewees’ gender. As meteorological variables were influenced by the diverse contexts found within a close distance inside the studied green space, results from this structured experiment suggest the need for micrometeorological diversity in the local context as a means to promote greater adaptive opportunities for green spaces users.
- Green space influence on thermal comfort: contrasting approaches in the assessment of conditions in Bragança (Portugal)Publication . Gonçalves, Artur; Ribeiro, A.C.; Nunes, Luís; Maia, Filipe; Feliciano, ManuelUrban greening has been widely recognised as a key factor to mitigate the adverse effects of urbanisation in a sustainable manner [1]. Green spaces characteristics include trees, soft surfaces and wind shelters that can influence thermal sensations by inducing changes in such variables as solar radiation, temperatures of surrounding surfaces, air temperature, humidity and wind speed [2,3]. As part of the ongoing research entitled GreenUrbe (PPCDT/AMB/59174/2004), both users surveys and structured experiments are being developed, trying to establish relation between green spaces characteristics and thermal comfort. The city of Bragança is located in north-eastern Portugal. Local climate is characterised by a cold rainy winter and relatively short (June to September) hot and dry summer.
- Urban climate studies: addressing the role of urban green spacesPublication . Gonçalves, Artur; Ribeiro, A.C.; Maia, Filipe; Pinto, M.V.; Feliciano, ManuelCities present a wide range of climate transformations resulting from changes induced by buildings and other artificial structures, including such effects as the urban heat island (UHI) and the changes in the ventilation patterns. Under these conditions, urban climate analysis is increasingly considered as a necessary activity that should be part of the urban planning practice. Although there has been a wide development of climate studies across different countries, further improvement is needed to address a wider diversity of geographic locations and conditions (Ren et al., 2010). Stewart and Oke (2012) defined a set of Local Climate Zones (LCZ) as a way to address such a complex reality, including both urban and periurban locations. As part of the European funded project BIOURB, a study is taking place in Bragança (Portugal) aiming at studying local urban climate, while establishing a basic methodology that can be used as a reference for cities located in the regions of the North of Portugal and Castilla-León (Spain). The methodology can be described as consisting on the integration of urban climate monitoring with the interpretation of major factors influencing local climate (topography, land use and artificial structures), allowing for the interpretation of major climate transformations, with the ultimate goal of providing urban design strategies. Urban climate monitoring is being carried out with a combination of twenty three temperature and relative humidity sensors, five wind anemometers and three weather stations. The location of these equipment addresses different LCZs and the potential rural to urban gradient, including several green spaces within the urban limits. Results from a full year campaign, show that while addressing a small, though complex, urban reality and despite the proximity to rural surroundings, the Urban Heat Island effect reaches intensity values over 5oC during the hot summer nights, thus showing the contrast between the higher temperatures resulting from the effects of artificial surfaces, anthropogenic heat and heat retention by buildings, and the lower temperatures observed in green spaces both within and outside the town. As urban climate study is still being carried out, preliminary results suggest green spaces are relevant assets in climate intervention by both diminishing thermal load, relevant under warm summer conditions and to potentially being associated to topographic dynamic processes such cold air drainage (valleys), wind reduction (woodlands) or wind enhancing (grasslands).