223
A recent study shows how urban microclimate affects the functions of buildings
in terms of thermal performance, proving that urban form has an effect on the UHI
phenomenon (Wong and Chen 2009). Speaking specifically of Italian cities, heat
islands are not caused by the anthropogenic heat produced by human activities, but
rather by the heat stored by urban surfaces (buildings, roads, parking lots) during
the day and then released gradually at night. This effect generates a nocturnal heat
island, insofar as the heat released does not allow the city to cool down as much as
the rural environments external to it.
The complexity of the UHI phenomenon is directly related to the relationship
between city and atmosphere; urban climate and atmospheric climate affect and
influence each other (Oke 2006b).
Usually, the aspects that influence climate, generating an urban microclimate
that is different from the climate of the atmosphere, (Shahmohamadi 2012) are the
following:
– amount of grass, permeable soil, trees, asphalt, and concrete;
– artificial heat released from buildings, air-conditioning systems, cars, and
production areas;
– surface water storage and lamination in favor of underground canals and drains;
– air pollution;
– urban ventilation.
Urban heat islands arise from extensive anthropization, or rather, it could be said
that the fewer the ecological properties of a city, the greater its heat island will be.
It is no coincidence that this effect had already been observed by meteorologist
Luke Howard for the first time in 1818, in London, at the height of that city’s expansion. At the time, it was not identified as a heat island
1 ; the term “island” was coined
when isotherms were used to map the city. When air temperatures are mapped
through isotherms, the city appears like an island compared to the surrounding rural
areas, which are differentiated by lower temperatures. On these bases, we started
our project by studying the different behaviors of the urban heat island of pilot
experiment city Padua vis-à-vis its different urban contexts. We chose this area also
taking into account our purpose of drafting an urban planning manual for the Veneto
Region to be delivered to municipal administrations in order to support their future
strategic choices in terms of mitigating the UHI phenomenon and adapting vulnerable urban areas to climate changes. Therefore, we picked this area for our study
also because it conforms to the urban and spatial characteristics of other cities and
areas of the Veneto region.
To conduct urban heat island effect analyses and surveys, we then went on to
selecting five pilot areas in the municipality of Padua, based on their location with
respect to a survey transect crossing the city along the north-west/south-east axis
1 The term “urban heat island” was coined in 1958 by Gordon Manley in an essay found in the
Quarterly Journal of the Royal Meteorology Society.
8 Mitigation of and Adaptation to UHI Phenomena: The Padua Case Study
A recent study shows how urban microclimate affects the functions of buildings
in terms of thermal performance, proving that urban form has an effect on the UHI
phenomenon (Wong and Chen 2009). Speaking specifically of Italian cities, heat
islands are not caused by the anthropogenic heat produced by human activities, but
rather by the heat stored by urban surfaces (buildings, roads, parking lots) during
the day and then released gradually at night. This effect generates a nocturnal heat
island, insofar as the heat released does not allow the city to cool down as much as
the rural environments external to it.
The complexity of the UHI phenomenon is directly related to the relationship
between city and atmosphere; urban climate and atmospheric climate affect and
influence each other (Oke 2006b).
Usually, the aspects that influence climate, generating an urban microclimate
that is different from the climate of the atmosphere, (Shahmohamadi 2012) are the
following:
– amount of grass, permeable soil, trees, asphalt, and concrete;
– artificial heat released from buildings, air-conditioning systems, cars, and
production areas;
– surface water storage and lamination in favor of underground canals and drains;
– air pollution;
– urban ventilation.
Urban heat islands arise from extensive anthropization, or rather, it could be said
that the fewer the ecological properties of a city, the greater its heat island will be.
It is no coincidence that this effect had already been observed by meteorologist
Luke Howard for the first time in 1818, in London, at the height of that city’s expansion. At the time, it was not identified as a heat island
1 ; the term “island” was coined
when isotherms were used to map the city. When air temperatures are mapped
through isotherms, the city appears like an island compared to the surrounding rural
areas, which are differentiated by lower temperatures. On these bases, we started
our project by studying the different behaviors of the urban heat island of pilot
experiment city Padua vis-à-vis its different urban contexts. We chose this area also
taking into account our purpose of drafting an urban planning manual for the Veneto
Region to be delivered to municipal administrations in order to support their future
strategic choices in terms of mitigating the UHI phenomenon and adapting vulnerable urban areas to climate changes. Therefore, we picked this area for our study
also because it conforms to the urban and spatial characteristics of other cities and
areas of the Veneto region.
To conduct urban heat island effect analyses and surveys, we then went on to
selecting five pilot areas in the municipality of Padua, based on their location with
respect to a survey transect crossing the city along the north-west/south-east axis
1 The term “urban heat island” was coined in 1958 by Gordon Manley in an essay found in the
Quarterly Journal of the Royal Meteorology Society.
8 Mitigation of and Adaptation to UHI Phenomena: The Padua Case Study