296
Referring to Table 10.1 , a changing of the albedo of wall and roof surfaces has
the strongest effect on temperature, causing a decrease of the UHI intensity by
nearly 2 °C.
Both vegetation scenarios show a decrease of about 1–1.3 °C. With 1.2 temperature
reduction, the effect is similar for the ‘Density’ case.
Because of insuffi cient observation data in the rural surrounding, it is diffi cult to
retrieve the UHI intensity from measurements. The difference between air temperatures observed at ‘Stuttgart Schwabenzentrum’ (37.4 °C) and at Stuttgart Hohenheim
in the near surrounding (33.1 °C) accounts for 4.3 °C, for August 13 18:00
UTC. Assuming a height dependent temperature decrease of 1 °C per 100 m between
urban (250 m NN) and rural (400 m NN) location, the adapted observed UHI
amounts to 3 °C. The second parameter in Table 10.1 describes the mean temperature
for the whole modelling period for one single urban grid cell in the centre of the city,
whereas all other parameters treat aerial statistics for one temporal snap-shot.
The above fi ndings describe the climatological and meteorological background
for the forthcoming mitigation and adaptation actions to reduce the urban heat
islands and its impacts. Besides the modeling results it is now of great importance
to fi nd the best urban planning strategy for the specifi c urban area of interest, considering
a mixture of different mitigation strategies. However, due to the coarse resolution it
is diffi cult to directly apply the measures proposed by that study. Rather, these kinds
of modelling studies can be used as a decision support and provide meteorological
boundary conditions for high resolution street scale models.
10.3 Transfering the Findings of the Pilot Action Study
to Urban Planning Process in Stuttgart
The fi ndings of the studies within the pilot action Stuttgart, have shown, that several
measure can be effectively reduce the UHI intensity and the impacts on urban living
and human health. However, reducing UHI intensity in a city, which is growing over
the centuries, requires deep changes in the city and building structure. Changing a
city to improve the urban climate is a hard and challenging transaction, which needs
a sustainable future-oriented urban planning. Most of the measures for reducing
UHI in a city are only effective by large-scale implementation, but changing a city
due to urban planning are mostly concentrated on single buildings or small areas
like existing brownfi elds. Additional diffi culties are a low awareness for the problems
caused by UHI by the public and political boards, existing national and internation
strategies for the future development of urban areas, which potential forces the UHI
intensity (for example the European sustainable development strategy, which
supports the development of more compact and more densed cities), a low number
of free available areas to set up measures like parks, contrary interests of public,
industry and economy and the ownership structure. Also, in Germany a legal basis
for the consideration of UHI related aspects in the urban planning process is
currently not available.
R. Rinke et al.
Referring to Table 10.1 , a changing of the albedo of wall and roof surfaces has
the strongest effect on temperature, causing a decrease of the UHI intensity by
nearly 2 °C.
Both vegetation scenarios show a decrease of about 1–1.3 °C. With 1.2 temperature
reduction, the effect is similar for the ‘Density’ case.
Because of insuffi cient observation data in the rural surrounding, it is diffi cult to
retrieve the UHI intensity from measurements. The difference between air temperatures observed at ‘Stuttgart Schwabenzentrum’ (37.4 °C) and at Stuttgart Hohenheim
in the near surrounding (33.1 °C) accounts for 4.3 °C, for August 13 18:00
UTC. Assuming a height dependent temperature decrease of 1 °C per 100 m between
urban (250 m NN) and rural (400 m NN) location, the adapted observed UHI
amounts to 3 °C. The second parameter in Table 10.1 describes the mean temperature
for the whole modelling period for one single urban grid cell in the centre of the city,
whereas all other parameters treat aerial statistics for one temporal snap-shot.
The above fi ndings describe the climatological and meteorological background
for the forthcoming mitigation and adaptation actions to reduce the urban heat
islands and its impacts. Besides the modeling results it is now of great importance
to fi nd the best urban planning strategy for the specifi c urban area of interest, considering
a mixture of different mitigation strategies. However, due to the coarse resolution it
is diffi cult to directly apply the measures proposed by that study. Rather, these kinds
of modelling studies can be used as a decision support and provide meteorological
boundary conditions for high resolution street scale models.
10.3 Transfering the Findings of the Pilot Action Study
to Urban Planning Process in Stuttgart
The fi ndings of the studies within the pilot action Stuttgart, have shown, that several
measure can be effectively reduce the UHI intensity and the impacts on urban living
and human health. However, reducing UHI intensity in a city, which is growing over
the centuries, requires deep changes in the city and building structure. Changing a
city to improve the urban climate is a hard and challenging transaction, which needs
a sustainable future-oriented urban planning. Most of the measures for reducing
UHI in a city are only effective by large-scale implementation, but changing a city
due to urban planning are mostly concentrated on single buildings or small areas
like existing brownfi elds. Additional diffi culties are a low awareness for the problems
caused by UHI by the public and political boards, existing national and internation
strategies for the future development of urban areas, which potential forces the UHI
intensity (for example the European sustainable development strategy, which
supports the development of more compact and more densed cities), a low number
of free available areas to set up measures like parks, contrary interests of public,
industry and economy and the ownership structure. Also, in Germany a legal basis
for the consideration of UHI related aspects in the urban planning process is
currently not available.
R. Rinke et al.