The Bioaerosols and Convective Storms (BACS) Field Campaigns: Variability in Cold Pool Characteristics and Aerosol Responses

Bioaerosols have important impacts on human health and potentially on weather and climate through aerosol–cloud interactions. Reciprocally, weather systems can have a large impact on bioaerosols both indirectly through ecosystem-level influences and by playing a more direct role in bioaerosol emission, deposition, and transport. In this work, we discuss the design and initial findings of the Bioaerosols and Convective Storms (BACS) field campaigns, a project targeting the interplay of these two effects. Two BACS field campaigns were conducted in the springs of 2022 and 2023, examining the dynamics of speciated and cloud-relevant aerosol and, especially, bioaerosol observations surrounding precipitation events and cold pool outflows from convective storms. A multifaceted deployment strategy was used, leveraging a combination of online and offline measurements of aerosol and bioaerosol distributions, cloud-relevant properties, and chemical tracers in the context of atmospheric state measurements. The observational strategy included measurements at ground level, a 9-m flux tower, and simultaneous stacked column and profiling multirotor drone measurements and radiosonde launches. Aerosol and bioaerosol responses to precipitation and cold pool events are examined within this manuscript through several case studies highlighting that similar events can produce very different aerosol responses. Reasons for this variability are hypothesized and discussed in the context of our campaign data, and targets for future investigations are suggested. Significance Statement This work is motivated by understanding a phenomenon with direct human impacts; storm lofting and transport of bioaerosols are known to cause health impacts such as “thunderstorm asthma,” while the same sources of bioaerosols may additionally impact storm evolution. This work describes an extensive campaign dataset, showcasing two cases to highlight how the dataset can be used to probe these questions and raising some of the crucial scientific questions requiring further investigation.