Interactions of Marine Aerosols and Turbulence Towards Understanding of Fog Formation in the Marine Boundary Layer

Marine fog poses significant challenges for mariners and motorists especially when it moves into nearby land and bay areas, as visibility could reduce to less than one kilometer. Despite its impact, the complex interactions between aerosols and turbulence contribute to the continued challenges in prediction and physical interpretation. This study aims to deepen our understanding of the microphysical processes driving fog formation in the marine atmospheric boundary layer, specifically focusing on the mechanisms that govern aerosol activation. To achieve this, we utilize a large-eddy simulation coupled with a Lagrangian cloud model (LES-LCM) scheme, which resolves the activation and tracking of individual super-droplets. The LES is initialized with thermodynamic conditions measured during the recent FATIMA field campaign at Sable Island, Nova Scotia, Canada. For the aerosols, we prescribe accumulation mode aerosols throughout the computational domain as an initial condition while continuously producing coarse mode marine aerosols on the sea surface based on a source function. As recent studies suggest, most of the activated aerosols are originated within the fog layer height due to supersaturation with very limited evidence of entrainment. By examining key microphysical properties within the fog layer such as activated and non-activated droplet size distribution, liquid water content, visibility, as well as hygroscopic growth, we will be gaining a deeper understanding of the fog life cycle and aerosols activation dynamics through the relationships of these properties.