Fog can be predicted only a few hours in advance, if at all, because it's not well understood what causes it
A major scientific field study of marine fog off the east coast of Canada is about to start.
The research is funded by the U.S. Department of Defense and hopes to better predict one of the most unpredictable weather phenomena: fog.
Fog can quickly ruin visibility everywhere from harbours to highways to airports, and can interfere with weapons systems. But how it's created is not deeply understood, which is one reason fog can be predicted only a few hours in advance, if at all.
"Prediction is critical because every year in Canada approximately 50 to 60 people die because of the visibility for fog-related issues," said Ismail Gultepe, a research scientist from the Department of Environment and Climate Change Canada who is involved in the project.
Researchers chose to study the greater Grand Banks area in the North Atlantic as it's one of the foggiest places in summertime, along with the Yellow Sea off China. In 2023, the research study will move to the Yellow Sea.
"I would say this is the largest fog project ever undertaken so far," said Joe Fernando, of Notre Dame University in Indiana who is leading the study.
He spoke from inside a hangar at Halifax Stanfield Airport, where more than four tonnes of atmospheric measuring equipment was being flown to Sable Island, 300 kilometres southeast of Halifax.
Instruments will also be deployed from the Irving-owned offshore supply ship Atlantic Condor, which has been chartered for a month-long mission in July. The ship will cruise from Sable Island to the Grand Banks.
"The overall project goal is to improve the predictability of marine fog to the extent possible. It is very difficult to predict, one of the least predictable in marine meteorology," said Fernando.
The mystery of fog
Fog is created when water droplets form around particles but interaction of all the atmospheric processes involved is not well understood.
"Fog is rapidly changing and that is the difficulty. It is rapidly coming, rapidly going, and we don't know how long it'll stay," said Fernando.
The U.S. Office of Naval Research commissioned the $7.5 million study. The data gathered is not classified.
Fernando said an important element of the study includes "directed energy laser beam propagation through the atmosphere so that the targets coming in can be nullified by the laser beam."
Dozens of scientists are involved, including Canadian researchers from the Department of Environment and Climate Change Canada, York University, the Department of Fisheries and Oceans, the Marine Environmental Observation, Prediction and Response Network and Dalhousie University in Halifax.
The Atlantic Condor will be carrying instruments from the lab of Rachel Chang.
The aerosol scientist at Dalhousie will measure the size and number of particles in the atmosphere and how they affect fog visibility and duration.
She's also studying droplets that form around a salt particle and those that form around industrial emissions blown into the area.
"That's actually the heart of what I'm really interested in, is whether the source of the particles — whether they're coming from the ocean or coming from emissions — and whether that really affects visibility or not."
Ismail Gultepe at the Department of Environment and Climate Change Canada is also investigating the impact of climate change on the creation and disappearance of fog. The more water vapour created in the open ocean, the more fog, he said.
"That's why we like to find out how the fog survives and changes in climatic conditions," Gultepte said, adding an important outcome will be improved modelling to predict fog.
The project is known as FATIMA, for Fog and Turbulence Interactions in the Marine Atmosphere.
The study will measure wind turbulence, fog micro-physics and chemistry, cloud height, water vapours and other conditions. It will use weather balloons, radar and lidar.
The Atlantic Condor will also deploy a remotely piloted small vessel and glider that will make upper ocean and lower atmospheric measurements.
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