ABSTRACT
A well-defined linear space such as an urban street or pedestrian pathway is a special case in terms of urban microclimate. This type of three-dimensional arrangement, as discussed in Chapter 1, may be described as an urban canyon – which is defined geometrically by the direction of its long axis and its characteristic height-to-width (H/W), or aspect, ratio. As a model, the urban canyon has a number of distinguishing features that are of interest when thinking about climate-responsive urban design:
The urban canyon has been the focus of numerous urban climate studies, both as a framework for describing urban canopy-layer conditions at the micro-scale, and as a building block for describing the larger urban surface at the meso-scale (see Chapter 1 for a description of these scale levels).
Compared to more inclusive descriptions of open space, the urban canyon model makes it possible to simplify geometric relationships by reducing the description of the space to an essentially two-dimensional cross-section (assuming a semi-infinite length along which the ratio of average building height to street width is constant).
Using simplified geometry, it is possible to clarify and highlight climatic effects that are related to fundamental issues such as urban density.
