A parameterization for urban areas has been incorporated into the Community Land Model (CLMU) as part of the Community Climate System Model (CCSM), a global climate model housed at the National Center for Atmospheric Research (NCAR). The urban representation is based on the “urban canyon” concept of Oke (1987) in which the canyon geometry is described by building height to width ratio. The canyon system consists of roofs, walls, and canyon floor. Walls are further divided into shaded and sunlit components. The canyon floor is divided into pervious (e.g., residential lawns, parks) and impervious (e.g., roads, parking lots, sidewalks) fractions. The ability of the urban model to represent the energy balance of cities and to reproduce known features of urban climatology (most notably, the urban heat island) has been demonstrated in published research.

The primary purpose of the urban model as coupled to a global climate model is to provide climate and climate-change information (e.g., near-surface air temperature and humidity, surface hydrology, etc.) for urban environments, where the majority of people work and live. Here, we demonstrate the ability of the model to provide this information. Results from global coupled simulations of present-day climate and future climate (2100) will be presented. These simulations make use of global datasets of urban extent, morphology, and radiative and thermal properties of urban materials developed by the University of Kansas. The analysis on present-day climate will focus on contrasting urban and rural near-surface air temperature and humidity and surface hydrology. Analysis of future climate simulation will compare the effects of urbanization-induced climate change and greenhouse gas-induced climate change. Examples of integrating urban datasets (e.g., population density) with urban model output using GIS to evaluate potential impacts of urban systems on human health and wellbeing will also be discussed.