Urban modifications in a Mesoscale Meteorological Model and the effects on near-surface variables in an arid metropolitan region

The single urban category in the existing 24-category U.S. Geological Survey land cover classification used in MM5 was divided into three classes to account for heterogeneity of urban land cover.

Updated land cover data were derived from 1998 Landsat Thematic Mapper satellite images. The composition of the urban land use classes in terms of typical fractions of vegetation and anthropogenic surfaces was determined from ground-truth information, allowing a variety of moisture availability for evaporation by land cover class. Bulk approaches for characteristics of the urban surface energy budget, such as heat storage, the production of anthropogenic heat, and radiation trapping, were introduced in MM5's Medium Range Forecast boundary layer scheme and slab land surface model.