Understanding the Impacts of Convective Storms on Bioaerosols in a Grassland Environment
TERESA FELDMAN, Janeshta Fernando, Chamari Mampage, Claudia Mignani, Marina Nieto-Caballero, Thomas C. J. Hill, Brian Heffernan, Drew Juergensen, Christine Neumaier, Tyler Barbero, Charles Davis, Lexi Sherman, Ben Ascher, Jacob Escobedo, Nick Falk, Sean Freeman, Gabrielle Leung, Allie Mazurek, Daniel Veloso-Aguila, Leah Grant, Susan van den Heever, Russell Perkins, Paul DeMott, Sonia Kreidenweis, Elizabeth Stone, University of Iowa
Abstract Number: 558
Working Group: Bioaerosols
Abstract
Bioaerosol can be transported, emitted, and transformed in thunderstorms, and may alter cloud microphysics as cloud condensation and ice nuclei. To investigate dynamics between bioaerosol and convective storms, bioaerosol were characterized in a grassland environment in the BioAerosol and Convective Storms (BACS) field campaigns in 2022 and 2023. Storms were evaluated in Northern Colorado using drones and radiosondes, fluorescent particles were measured by single particle fluorescence spectroscopy as a proxy for bioaerosols, and aerosol samples were collected for offline analysis. Precipitation events typically increased concentrations of fluorescent particles by at least 2x. Cold pools, which consist of denser, cooler, and sometimes more humid air than its environment, and form and expand under thunderstorms, triggered varying bioaerosol responses. On June 8, 2023, two cold pools and rainfall occurred over three hours, with peak fluorescent particle number concentrations relative to background increasing by 5x during the first cold pool, 15x during precipitation, and 5x during the second cold pool. The cold pools increased sub- and supermicron fluorescent particles associated with bacteria and fungal spores, while rainfall increased supermicron fluorescence types associated with fungal spores. Offline aerosol measurements of a fungal spore tracer (mannitol) concurrently increased. On June 2, 2023, three cold pools occurred over seven hours with no rainfall, with concentrations increasing by 2x during the first cold pool, decreasing by 1.5x for the second, and decreasing by 5x for the third. The first cold pool increased submicron types associated with bacteria, while the second and third primarily decreased supermicron fluorescent particles associated with fungal spores. Differences in fluorescent particle responses seem to be meteorologically driven, with increased concentrations during cold pools often being associated with stronger wind gusts and temperature perturbations. Future analysis will examine the role of these bioaerosols as ice nucleating particles and their potential feedbacks on thunderstorms.