Geoscience Reference
In-Depth Information
The aim of this text was not to describe different types of models, but to
illustrate several procedures based on Lisbon study cases both at the mesoscale and
at the microscale. In the study of the urban mesoclimatic patterns of Lisbon, the
empirical (statistical) model has made use of a great number of spatialized
geographic variables within a 250 m side grid. The multiple regression technique is
easy to apply and allows us to separate the influence of urban and other local
geographical factors (independent variables) in the observed urban climate features.
Several of these were easy to quantify (altitude, latitude, distance to the river); other
variables have required the use and/or processing of satellite data, detailed
cartography, and sometimes field surveys (NDVI, percentage of built-up area, mean
building height). The modeling of PET has been carried out at the microscale based
on a similar procedure. The geometry of the city district had to be thoroughly
represented in order i) to construct indices (such as SVF) susceptible of “explaining”
spatial variation of meteorological parameter or thermal indices; ii) to use the
numerical models of microclimatic simulations, such as the
ENVI-met
and the
radiation and bioclimate model such as
RayMan
. Numerous physical representations
of the geographical areas studied and at different scales were used (Lisbon and the
city-district of Telheiras) for wind modeling at the mesoscale and at the microscale:
digital terrain models, land cover, canyon geometry, built density, building height.
For the city district study, a scale model with all the details of the geographic
features had to be constructed (buildings, trees, etc).
Once the researchers have carried out accurate urban climatologic studies
(including monitoring, constructing models, validating models), then it will it be
possible to proceed to Oke's last three “research modes” (see above) [OKE 06a].
This will allow climatologic issues to be useful to society either in planning and
design purposes (mode 6), or impact assessment, including the cost of urban climate
and the “cost of inaction” when facing global and local warming in cities, assessing
space cooling needs and costs, as well as energy consumption (mode 7). Finally
urban climatologists may act in policies development and application (mode 8).
5.10. Acknowledgements
I am indebted to Henrique Andrade and António Lopes, first PhD students and
now colleagues, for their valuable contribution to the research in bio- and urban
climatology, for the frequent discussions and exchange of views over these issues,
all of which have greatly contributed to the development and dissemination of the
above topics, for their attentive and critical review of parts of this text and for the
use of some original images. I am grateful to João Vasconcelos for the use of Figure
5.11 and for the recent bibliography on Lisbon breezes, to Teresa Vaz for her
valuable help with the bibliography and figures and to Teresa Sutcliffe for English
proofreading of this text. Part of this research has been carried out in the frame of
the UrbKlim Project (POCI/GEO/61148/2004), financed by FCT and FEDER
(Operational Programme for Science and Innovation 2010) and of the project
“Climatic Guidelines for Planning in Lisbon”, financed by the Municipality of
Lisbon. Last but not least, Andreas Matzarakis, consultant of the Urbklim project,
must be warmly thanked for his helpful comments on two versions of this chapter.
