Variability of the Urban Heat Island in Raleigh, NC

As cities continue to grow, increasing areas covered by buildings and paved surfaces are yielding larger urban heat islands. Within an urban heat island, local differences such as land cover, tree cover, irrigation, and proximity to tall buildings create spatial variability in air temperature. These small-scale temperature variations can affect human comfort as well as increase the energy required to cool nearby buildings. For this study, five temperature loggers were deployed for several months across sites on the campus of North Carolina State University and in Raleigh, NC. Sites include two parking lots, two forested areas, and a built-up area near downtown Raleigh. All sensors were placed in bushes to minimize the impacts of direct solar radiation. We compare the temperature time series among sites and analyze differences across the diurnal cycle. With this information, we are able to examine how variations in ground cover and proximity to buildings and trees contribute to differences among microclimates within urban areas. We also examine changes to the diurnal cycle of temperature among our sites during the passage of Hurricane Florence in September 2018.