# Urban canyons

From AMS Glossary

## urban canyons

The characteristic geometry formed by a city street and its flanking buildings.

Together with the intervening roofs they provide a first-order repetitive structure to cities with characteristic patterns of sunlight and shade and cross-street vortices. Commonly described by their nondimensional aspect ratio

*H*/*W*, where*H*is the mean height of the buildings and*W*the width of the street.