Defining the Spatial and Average Intensity of the Louisville Urban Heat Island

A quantitative assessment of the urban heat island (UHI) in Louisville, Kentucky was conducted through climatological analysis of five observation stations over a 5-year period from 2009–2013. Results indicate the presence of a large UHI extending beyond 40 km, with an average intensity of 4.84°C between the most rural station and the urban control. By investigating temperature differences between all stations based on time and meteorological conditions, it was found that the UHI is especially amplified during the nighttime hours of 2300-0700 LST and in the presence of weak winds (< 3.0 ms-1), little to no cloud cover, and no precipitation. The heat island was negligible during the midday hours. This study indicated the necessity of a mesonet in this region, given the poor spatial resolution of the existing network.