Abstract
Fog constitutes a thick, opaque blanket of air hugging the Earth’s surface, laden with small water droplets or ice crystals. Fog disrupts transportation, poses security threats, disorients human perception and impacts communications and ecosystems. Collusion of atmospheric, terrestrial and hydrologic processes produces fog droplets that pullulate over hygroscopic aerosols that act as condensation nuclei. Marine fog is particularly complex, since underlying dynamic, thermodynamic and (bio)physicochemical processes span fifteen decades of spatial scales, from megameter-sized synoptic weather systems to nanometer-scale bioaerosols. This paper overviews the first international field campaign (Fatima-GB) of the project dubbed Fatima (Fog and turbulence interactions in the marine atmosphere) conducted during 01-31 July, 2022 in the Grand Banks region of North Atlantic. Therein, weather systems and commingling cold and warm oceanic waters provide entrée for fog genesis. Measurement platforms included an islet southwest of Nova Scotia (Sable Island), a research vessel (Atlantic Condor), an offshore Oil Platform and autonomous surface vehicles. The instrument array comprised of extant remote and in-situ sensors augmented by novel sensing systems prototyped and deployed in marine fog to penetrate the smallest scales of turbulence, examine aerosols, and quantify radiation budget. The comprehensive data set so gathered, together with satellite and reanalysis products, mesoscale-model and large-eddy simulations demonstrated that the long-held hypotheses of marine fog formation by warm air advection over colder water and in areas of enhanced (shelf) turbulence need to be revisited. The study also elicited new phenomena, for example, the Fog Shadow (clearings of fog downstream of islands).
© 2025 American Meteorological Society. This is an Author Accepted Manuscript distributed under the terms of the default AMS reuse license. For information regarding reuse and general copyright information, consult the AMS Copyright Policy (www.ametsoc.org/PUBSReuseLicenses).
