A geo-referenced database for surface roughness parameters over Greater Manchester

In this presentation information on urban morphology available for Greater Manchester in northwest England is analysed, and an approach to derive the roughness parameters needed to model the surface sensible heat flux is described. A surface morphologic database for Greater Manchester, developed from analysis of digitised geo-referenced data of the surface elements height (Cities Revealed Building Heights Data and Environment Agency data), aerial photography, maps and field surveys, is described. Initially, data of a sample area of Greater Manchester are analysed. Land-use categories are established for Greater Manchester, and reference morphologic parameters are attributed to each land-use category. The fraction of urbanised area and model surface morphologic parameters, such as the surface elements height (zH) and frontal area index (λF), are estimated and mapped over a rectangular grid of 1km x 1km resolution, for the Greater Manchester study area. Using these values it was possible to obtain model estimates of the zero-plan displacement height (zD) and roughness height for momentum (z0M) for each domain cell.