Urban microclimate

This paper presents a logistic proposal for the research project related to thermal comfort in Rio de Janeiro’s open spaces. Part of the investigation consists of collecting weather data and applying a thermal sensation survey to pedestrians in Rio de Janeiro city’s centre. The weather station used is a Davis-Pro2, composed by a cylindrical module body moulded on plastic and sustained by a central tube attached to a tripod, both in galvanized iron.

Since 2007, more than half of world population lives in urban areas and its activity leads to an increase of building energy demand notably in summer. The temperature rise of densely built areas is mainly due to landscaping and anthropogenic heat fluxes such as air conditioning systems. Acting on urban landscaping, building density, surface albedo or green area can mitigate the urban heat island with direct and indirect improvement of building energy performances.  

This research studies the possibility of introducing combinations of specific mitigation techniques for the urban heat island effect (UHI) in Athens, Greece. A variety of factors, such as surface cover, dense traffic, anthropogenic heat release and urban characteristics including geographic features and climate conditions interact with one another to create UHI, which is becoming increasingly evident also due to the changing climate, which in this region is expected to increase the duration of hot spells and the frequency of heat waves.

An urban heat island results in higher urban temperatures than the surrounding area and is considered as the most documented phenomenon of climate change. This increase in urban temperature has a serious impact on the energy consumption for cooling and also contributes to higher urban pollution levels. Athens suffers from high summer temperatures that affect the quality of life of citizens. In response to the problem, a major rehabilitation plan was designed and applied, based on the use of advanced mitigation techniques.

Meteorological measurements required for the development of a design scheme that responds to the local environment are generally recorded by the weather service in stations that are assumed to be representative of the surrounding region. However, no account is taken of the changes in conditions caused by urban development, even though differences between meteorological conditions within cities compared with adjacent rural areas (the heat island effect) may be substantial.