eTheses Repository - University of Birmingham

4.4 Summary
The results presented in Section 4.3 from the implementation of the BEP urban scheme for
an idealised domain show that:
• The new modelling system of METRAS+BEP reproduces documented aspects of
the air flow over urban areas, such as the circulation patterns over the city, the UHI
and the neutral layer above the city, which are better than those produced by the
original version of METRAS.
• The results of this implementation are also in excellent qualitative agreement with
those presented in Martilli et al. (2002) and in Hamdi (2005), which is an indirect
validation of the fact that the scheme has been correctly implemented and the
results are correct.
• The results of the implementation are also consistent with a range of field
campaigns.
In order to gain a further understanding of how the BEP scheme affects model results under
a variety of different conditions, and to further test model results, a sensitivity study was
undertaken to examine the robustness of the METRAS+BEP modelling system. The
sensitivity study investigated the influence of the city characteristics (e.g. building
morphology, albedo and temperature inside the buildings), that of the rural surroundings (in
particular the different land cover classes in the METRAS model) and synoptic conditions
(e.g. the wind speed) on the local meteorology, UHI and the mesoscale circulation. These
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