The Houston Urban Heat Island Effect: Motivation and Initial Findings from the 2022 TRACER Field Campaign

Cities and other urban areas commonly exhibit the urban heat island (UHI) effect, where air temperatures within the built-up area are higher than the surrounding rural region. Man-made materials common in urban areas like concrete, asphalt, and building materials directly reflect as well as absorb and emit radiation more efficiently than natural materials (e.g., grass, trees, etc.). These changes can have a significant impact on the radiation balance within an urban area. Additionally, urbanization typically results in lower latent heat fluxes. These changes in the radiation and surface energy balance typically cause near-surface air temperatures to rise above rural temperatures within a city. Due to the diurnal cycle of the radiation and surface energy balance, the UHI enhancement, defined as the difference in temperature between an urban and nearby rural area, also varies depending on time of day. In cities near bodies of water, the UHI effects and evolution over time are further complicated due to the additional temperature gradients created by land/water airmass interactions in the boundary layer.

This presentation will take an initial look at the UHI effects present in the greater Houston, TX area during the 2022 TRACER field campaign. The UHI is expected to play an important role in local meteorology in Houston due to the size of the city and geographical features. Houston is the fourth largest city in the United States by population, and sprawls over a large urban and industrial area bordered by the Gulf of Mexico and multiple bays. Near-surface air temperature at stations throughout the greater Houston area are analyzed to determine the spatial extent of the UHI. These findings and future analysis, coupled with boundary layer measurements, will help determine if the UHI and bay/sea/land breezes common in Houston interact significantly with one another.