20 On the Urban Canopy Effects in Regional Climate Simulations …
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compare the effects of different urban paramterizations in two atmospheric models,
regional climate model RegCM and WRF.
20.2 Experiments Setup
The regional climate model RegCM4.2 [4] was used with its BATS land surface
scheme [3] extended by Huszar et al. [9], following Chen et al. [2], with the Singlelayer Urban Canopy Model (SLUCM) that accounts for the most relevant processes
specific to the urban environment including the anthropogenic heat release. In newer
version RegCM4.5 used with CLM4.5 scheme, internal option of urban parameterization is included in terms of SLUCM by Oleson et al. [14]. In addition, model WRF
in the adaptation for regional climate simulations was tested with all the options
of urban parameterizations available, i.e. bulk version, where actually there is are
no urban proceses included, except the land use parameters and properties are set
with proper values adequate the artificial surfaces in the urban environment. Similar implementation of SLUCM [2] is another option in WRF, as well as the more
complex multi-layer scheme BEP-BEM including energetics of buildings as well,
following Martilli et al. [11]. The simulations for the central European region have
been performed for the years of 2001–2010 in 10 km resolution, with all the settings.
The comparison of urban effects in the individual simulations is presented against
the “control” simulations when urban land use was replaced by typical land use of
the urban vicinity.
20.3 Results and Conclusions
In Fig. 20.1 we present the comparison of simulations with selected urban parameterizations against the experiment with no-urban”control” setting. It is clearly seen
that the effects of UHI differ significantly depending on the parameterization choice
and model implementation, however, common features of UHI behavior are reproduced reasonably well. In summer night, as expected, under specific conditions of
heat waves, the intensity of UHI can achieve for mid-size cities like Prague quite
high values of about 5 °C, which is in accordance with observations. For larger cities,
or with higher urbanization due to more heavy population, like e.g. Budapest, the
simulations can reach up to 10 °C intensity which is value reffered to in literature.
The models performance in terms of daily course of temperature for all the simulations and selected urban area of Prague has been improved and urban effects
due to urban parameterization are clearly identified. Even in WRF cases the bulk
parameterization can reasonably reproduce the temperature effect, except for winter,
where anthropogenic heat release dominates, which is best reproduced by BEP-BEM
parameterization. However, the results for surface wind and mixing height clearly
121
compare the effects of different urban paramterizations in two atmospheric models,
regional climate model RegCM and WRF.
20.2 Experiments Setup
The regional climate model RegCM4.2 [4] was used with its BATS land surface
scheme [3] extended by Huszar et al. [9], following Chen et al. [2], with the Singlelayer Urban Canopy Model (SLUCM) that accounts for the most relevant processes
specific to the urban environment including the anthropogenic heat release. In newer
version RegCM4.5 used with CLM4.5 scheme, internal option of urban parameterization is included in terms of SLUCM by Oleson et al. [14]. In addition, model WRF
in the adaptation for regional climate simulations was tested with all the options
of urban parameterizations available, i.e. bulk version, where actually there is are
no urban proceses included, except the land use parameters and properties are set
with proper values adequate the artificial surfaces in the urban environment. Similar implementation of SLUCM [2] is another option in WRF, as well as the more
complex multi-layer scheme BEP-BEM including energetics of buildings as well,
following Martilli et al. [11]. The simulations for the central European region have
been performed for the years of 2001–2010 in 10 km resolution, with all the settings.
The comparison of urban effects in the individual simulations is presented against
the “control” simulations when urban land use was replaced by typical land use of
the urban vicinity.
20.3 Results and Conclusions
In Fig. 20.1 we present the comparison of simulations with selected urban parameterizations against the experiment with no-urban”control” setting. It is clearly seen
that the effects of UHI differ significantly depending on the parameterization choice
and model implementation, however, common features of UHI behavior are reproduced reasonably well. In summer night, as expected, under specific conditions of
heat waves, the intensity of UHI can achieve for mid-size cities like Prague quite
high values of about 5 °C, which is in accordance with observations. For larger cities,
or with higher urbanization due to more heavy population, like e.g. Budapest, the
simulations can reach up to 10 °C intensity which is value reffered to in literature.
The models performance in terms of daily course of temperature for all the simulations and selected urban area of Prague has been improved and urban effects
due to urban parameterization are clearly identified. Even in WRF cases the bulk
parameterization can reasonably reproduce the temperature effect, except for winter,
where anthropogenic heat release dominates, which is best reproduced by BEP-BEM
parameterization. However, the results for surface wind and mixing height clearly