Investigating the Effects of the Urban Heat Island on PBL Thermodynamics Relevant to Deep Convection using Uncrewed Aircraft Systems

The expansion of urbanization necessitates research into the effects of changing land use/land cover (LULC) on regional weather and climate. One of these effects is the impact of the Urban Heat Island (UHI) on deep convection. The Micro Small UAS for Atmospheric Low Level Environment Sampling (MicroSCALES) project intends to use uncrewed aircraft systems (UAS) distributed across Tulsa, OK, to further our understanding of urban-impacted environments. We will use these data to investigate the impacts of urban-rural differences on the thermodynamics of the planetary boundary layer (PBL) relevant to deep convection.
The physical properties of the urban surface have impacted the environmental energy budget by re-emitting more energy and changing the moisture composition. These changes manifest themselves as variations in sensible and latent heat, both of which are important for deep convection. This relationship between urban modifications of the environment and deep convection is not entirely understood. Since urbanization affects multiple environmental factors, it is important to study the tradeoffs between these changes and recognize their impacts on PBL thermodynamics.
We hypothesize that the differences in LULC associated with urban environments will affect the thermodynamics of the PBL to enhance convective potential. We believe that there may be areas of increased CAPE created by higher sensible heat within the UHI, but also by the layering of the UHI plume and surrounding rural PBL. To test this hypothesis, the Small UAS for Atmospheric Low Level Environmental Samling (SCALES) project will collect data in Tulsa, OK 9-13 September 2024. The MicroSCALES component of SCALES will use a network of 13 UAS distributed across sites that are upstream, within, and downstream of Tulsa. The UAS teams will fly simultaneously, collecting vertical profiles up to 1000 m over a period of six hours. In addition to that, multiple radiosondes will be launched at a site upstream of the city and at a site five kilometers downstream of Tulsa. The flight periods will alternate between morning and evening to capture the spatial and temporal evolution of the UHI and its corresponding effect on PBL thermodynamics.
Analysis will include modifying upstream radiosondes launches with urban UAS profiles. This will allow us to evaluate how low-level urban modifications impact full-tropospheric thermodynamics throughout the urban area. Additional analysis will aim to characterize the extent and magnitude of the urban plume and its diurnal evolution. The SCALES project will allow us to improve our understanding of urban environments, improve urban forecasting, as well as gain a better understanding of the mechanism behind urban-impacted deep convection.