Investigating Changes of Summer Urban Heat Island in Kansas City from 2000-2023 with Remote Sensing

Rising temperatures are increasingly affecting human health and finances, particularly in urban areas where the landscape materials absorb more shortwave solar radiation and re-emit more longwave radiation, intensifying the heat effects. This phenomenon, known as the urban heat island (UHI) effect, has been observed through thermal imagery collected by satellites such as the MODIS and the Landsat. The availability of reliable satellite data spans only the past several decades, with high-quality thermal imagery accessible for approximately thirty years. Consequently, there has been limited analysis of the UHI stress in various cities over time. This study investigates the UHI effect in the Kansas City Metropolitan Area (KCMA) using MODIS and Landsat datasets, focusing on the changes observed during the boreal summer seasons from 2000 through 2023. By employing two different methods to calculate the UHI intensity, we find that UHI intensity in the KCMA has increased in areas with consistently dense urban development where urban materials present have had little to no change during the period examined. However, current UHI calculation methods may have limitations, particularly during heatwave events. While urban surface temperatures rise during heatwaves, surrounding rural areas also experience elevated temperatures beyond the urban surface gains, which reduces the calculated UHI intensity. This suggests a weakening of the UHI effect during heatwave events, despite higher urban temperatures. Our study highlights that the rising atmospheric temperatures, coupled with urban topography and urban airflow dynamics, are slowing the release of surface heat, further intensifying the UHI effect. Even without accounting for the amplifying effects of heatwaves, our findings indicate that the UHI values have been steadily increasing in the well-established urbanized areas and are likely to continue rising in the future.