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M. Vuckovic, K. Kiesel, A. Mahdavi:
"The sources and impliactions of urban climate variance in Vienna";
Talk: Third International Conference on Countermeasures to Urban Heat Island, Venedig, Italien; 2014-10-13 - 2014-10-15; in: "Proceedings of the Third International Conference on Countermeasures to Urban Heat Island", H. Akbari et al. (ed.); (2014), 8 pages.

The urban microclimate and its spatio-temporal variance play a crucial role in
architectural and urban design. Specifically, all assertions pertaining to the future energy
performance of buildings and their indoor climate depend on the assumptions regarding microclimatic
boundary conditions. Currently, predictive models of the thermal performance of
building designs are typically based on computational methods that use heat balance models of
different level of complexity. The representation of microclimatic boundary conditions in these
computational applications is based on standardized data (so-called reference weather files).
However, such standardized dynamic weather files are limited in a critical sense: They are,
strictly speaking, representative only for the location of the associated source of data, e.g. the
weather station location.
In the present paper, we specifically present long-term data that document the finestructure
of microclimatic variance in the city of Vienna, Austria. Thereby, long-term highresolution
and dynamic data streams across six key locations are obtained, structured, and
analyzed. The results of this analysis reveal significant variations that could not be ignored while
assessing thermal performance of buildings without the risk of erroneous conclusions.
Furthermore, to explore the explanatory potential of a number of variables that are hypothesized
to contribute to the urban microclimate variance (e.g. topographic and morphological factors,
semantic properties of urban surfaces), their respective values were computed for specific urban
areas associated with each of the weather stations. The results of this exploration point to the
existence of district aggregate morphological and physical attributes that could support the
understanding and prediction of local differences in the urban climate.

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