Aerosol Vertical Distributions Shaped by Boundary Layer Dynamics in a Coastal Urban Environment: Insights from the TRACER Campaign

Abstract. Aerosol vertical distributions are a major source of uncertainty in quantifying aerosol–cloud–climate interactions. Using observations collected during the 2022 TRACER campaign in Houston, Texas, we investigate how Atmospheric boundary layer dynamics shape the vertical structure of aerosol populations in a coastal urban environment. Our lidar retrieval combines micropulse lidar backscatter with ground-based aerosol measurements to obtain aerosol concentration profiles. We introduce a new parameterized fitting function that captures the characteristic S-shaped aerosol profiles associated with boundary layer processes. This parameterization is applied to case studies demonstrating how boundary-layer dynamics, including turbulent mixing, capping inversion strength, and sea-breeze circulations, govern aerosol vertical distributions. Finally, we estimate aerosol vertical profiles from boundary layer height and gradients in potential temperature profile using our proposed aerosol profile parameterization function. These findings provide a physically grounded parameterization for inferring aerosol vertical profiles in locations where aerosol sampling is limited to surface measurements.