277
greenings, or accessibility of roof gardens may also be defi ned in the Special
Conditions. Other issues addressed may include taking the necessary steps to enable
tree planting along streets and in public squares, determining the permissible percentage of sealing on a plot of land to reduce the level of soil sealing in park areas
or specifying whether arcades are to be built in the area (Fig. 9.11 ).
9.6.3.3 Modelling Measures and Their Impact with the Example
of Karlsplatz and Surroundings
Three adaptation measures were modelled for assessment of the city centre. The
scenarios include: a base case without measures, (1) tree planting, (2) roof greening
and (3) a combination of tree planting and roof greening. The fi gures below show
the difference in climate conditions between the current building stock and the simulated implementation of individual measures on a reference day. The models were
built by the Department of Building Physics and Building Ecology, Vienna
University of Technology using ENVI-met 4.0 (Mahdavi et al. 2014 ). Clearly visible are the differences in air temperature between the current situation and after the
simulated impact of the measures selected.
Results reveal that adaptation measures have the potential to reduce air temperature in the research areas on hot summer days. As expected different adaptation measures also have different levels of impact. Roof greening in the city centre has no
noticeable effect on air temperature in the open spaces of streets (scenario 2), while
trees do (scenario 1). The combination of the two selected measures proved particularly effective (scenario 3). Looking at the time patterns showed that differences in
air temperature are more distinct in the evening and during the night (see Fig. 9.12 ).
Fig. 9.12 The research area in the ENVI-met model and after implementation of selected adaptation measures, as well as average hourly temperature on a reference day, shown for the current
building stock and for the three adaptation scenarios (Source: Vienna University of
Technology, Mahdavi et al. 2014 )
9 Pilot Action City of Vienna – UHI-STRAT Vienna
greenings, or accessibility of roof gardens may also be defi ned in the Special
Conditions. Other issues addressed may include taking the necessary steps to enable
tree planting along streets and in public squares, determining the permissible percentage of sealing on a plot of land to reduce the level of soil sealing in park areas
or specifying whether arcades are to be built in the area (Fig. 9.11 ).
9.6.3.3 Modelling Measures and Their Impact with the Example
of Karlsplatz and Surroundings
Three adaptation measures were modelled for assessment of the city centre. The
scenarios include: a base case without measures, (1) tree planting, (2) roof greening
and (3) a combination of tree planting and roof greening. The fi gures below show
the difference in climate conditions between the current building stock and the simulated implementation of individual measures on a reference day. The models were
built by the Department of Building Physics and Building Ecology, Vienna
University of Technology using ENVI-met 4.0 (Mahdavi et al. 2014 ). Clearly visible are the differences in air temperature between the current situation and after the
simulated impact of the measures selected.
Results reveal that adaptation measures have the potential to reduce air temperature in the research areas on hot summer days. As expected different adaptation measures also have different levels of impact. Roof greening in the city centre has no
noticeable effect on air temperature in the open spaces of streets (scenario 2), while
trees do (scenario 1). The combination of the two selected measures proved particularly effective (scenario 3). Looking at the time patterns showed that differences in
air temperature are more distinct in the evening and during the night (see Fig. 9.12 ).
Fig. 9.12 The research area in the ENVI-met model and after implementation of selected adaptation measures, as well as average hourly temperature on a reference day, shown for the current
building stock and for the three adaptation scenarios (Source: Vienna University of
Technology, Mahdavi et al. 2014 )
9 Pilot Action City of Vienna – UHI-STRAT Vienna