Modulation of Urban Heat Island and Heat Waves under Current and Future Climate

Urban heat islands (UHI) are urban and city areas that are hotter than the surrounding rural areas. UHIs have have been studied extensively in the past, and have recently received greater attention due to implications for the environmental, health and energy sectors. A recent study found heat waves not only increase ambient air temperatures, but also intensify the difference between urban and rural temperatures. Adaptation and mitigation strategies suggest that cities should be redesigned with green/cool roof technology and urban areas should have additional surface moisture (e.g., artificial lakes). In the present study, we use the enhanced version of the single layer urban canopy model (SLUCM) with parameterized urban hydrological processes to analyze the 2006 North American heat wave. SLUCM was released with WRFV3.7, and enhancements include the ability to model anthropogenic latent heat, urban irrigation, evaporation from water holding engineered pavements, urban oasis effects and a multilayer green roof system. Our present course of investigation seeks to answer how green roof technology may have mitigated the 2006 heat wave, and how present mitigation procedures might perform under a climate-warming scenario. We use the SLUCM both with and without the multilayer green roof system to explore the influence of green roof technology during the 2006 heat wave. We then apply a climate signal perturbation to investigate the impact of a warming climate on the 2006 heat wave with and without green roof technology. The climate signal perturbation is obtained from the difference of 21 years of mean data in a future climate (2070-2090) and in the current climate (1985-2005) using the Community Climate System Model with representative concentration pathways (RCP8.5).