A simple energy balance model is created for use in developing mitigation strategies for the urban heat island effect. The model is initially applied to the city of Phoenix, Arizona. There are six primary contributions to the overall energy balance: incident solar radiation, anthropogenic heat input, conduction heat loss, outgoing evapotranspiration, outgoing convection, and outgoing emitted radiation. Meteorological data are input to the model, which then computes an urban characteristic temperature at a calculated time step for a specified time range. The model temperature is shown to have the same periodic behavior as the experimentally measured air temperatures. Predicted temperature changes, caused by increasing the average urban albedo, agree within 0.18C with comparable maximum surface temperature predictions from the fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model (MM5). The present model, while maintaining valid energy-balance physics, allows users to quickly and easily predict the relative effects of urban heat island mitigation measures. Representative mitigation strategies, namely changes in average albedo and long-wavelength emissivity are presented here. Increasing the albedo leads to the greater reduction in daytime maximum temperatures; increasing the emissivity leads to a greater reduction in nighttime minimum temperatures.

A zero-dimensional energy balance model was previously developed to serve as a user-friendly mitigation tool for practitioners seeking to study the urban heat island (UHI) effect. Accordingly, this established model is applied here to show the relative effects of four common mitigation strategies: increasing the overall (1) emissivity, (2) percentage of vegetated area, (3) thermal conductivity, and (4) albedo of the urban environment in a series of percentage increases by 5, 10, 15, and 20% from baseline values. In addition to modeling mitigation strategies, we present how the model can be utilized to evaluate human health vulnerability from excessive heat-related events, based on heat-related emergency service data from 2002 to 2006. The 24-h average heat index is shown to have the greatest correlation to heat-related emergency calls in the Phoenix (Arizona, USA) metropolitan region. The four modeled UHI mitigation strategies, taken in combination, would lead to a 48% reduction in annual heat-related emergency service calls, where increasing the albedo is the single most effective UHI mitigation strategy.