Numerical simulations to quantify the diurnal contrast in local climate trend induced by desert urbanization

The effect of urbanization on local climate is quantified by numerical simulations for five desert cities that represent a wide range of urban size, climate zone, and composition of land cover. Land-use land cover maps generated from Landsat data for 1985 and 2010, chosen as the start and end of a period of rapid urbanization, are used to constrain the surface boundary conditions for the numerical model. In this manner, this study focuses on the particular aspect of the effect of land-use changes on local climate. Within this scope, the results reveal a pattern of the climatic effect of desert urbanization with nighttime warming and weaker, but significant daytime cooling. This effect is confined to the urban area and is not sensitive to the size of the city or the detailed land cover types in the surrounding areas. The pattern is identified in both winter and summer. Exceptions to this pattern are found in a small number of cases when the noisiness of local circulation, specifically monsoon and land–sea breeze, overwhelms the climatic signal induced by land-use changes. The inter-cities’ differences in the temperature response to land-use change are also discussed.