Exploring Turbulence and Fog Characteristics in FATIMA

Fog is commonly defined as a reduction in horizontal visibility (<1 km) due to suspended water droplets with high relative humidity (>90%), which adversely affects light propagation and optical communication, critical for naval and commercial operations. Here, we examine the characteristics of turbulence and fog in maritime environments, using measurements from the Fog and Turbulence in the Marine Atmosphere (FATIMA) project aimed at increasing the understanding of the physics in the life cycle of a fog events. This study utilized turbulence fluxes from eddy-covariance calculations and vertical profiles from radiosonde and remote sensing instruments from two distinct geographic locations: the Grand Banks of Newfoundland, and the Yellow Sea where the data was collected during the intensive field campaigns in 2022 and 2023. This presentation will focus on how the maritime fog affects turbulence statistics in both regions. The results revealed that 23% of the soundings from the Yellow Sea and 38% on Sable Island contained fog layers at 15 meters or lower, with the average top of these layers being 285 m and 275 m, respectively. The findings highlighted the general stable stratification of the surface layer in the presence of fog, the unstable thermal stratification during periods of clear conditions, and the role of turbulence in fog microphysics and in near-surface visibility. This study contributes to a better understanding of fog dynamics and their impact on maritime navigation and meteorological predictions, ultimately providing new knowledge to improve model forecasts of fog.