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Clouds Could be Used to Monitor Sulfur Cap Compliance

Satellite images of the ship tracks near Cornwall, in southwest England. Credit: Edward Gryspeerdt, with data from NASA
Satellite images of the ship tracks near Cornwall, in southwest England. Credit: Edward Gryspeerdt, with data from NASA

By The Maritime Executive 2019-11-06 19:43:25

A study has shown that ships burning low sulfur fuels have less impact on cloud formation, something that could be used to monitor compliance with Sulfur Cap and Emission Control Area limits.

Emissions from ships contain several chemicals, including sulfate aerosols. The aerosols can act as seeds around which water droplets accumulate, causing ship “tracks” that are visible to satellites. 

Satellite tracking undertaken by the researchers demonstrated that the impact of ships on clouds largely disappeared in restricted areas. They studied over 17,000 ship tracks from satellite observations and matched them to the movements of individual ships using their onboard GPS. The study period covered the introduction of emission control areas around the coast of North America, the North Sea, the Baltic Sea and the English Channel.

“Currently, it is hard for regulators to know what ships are doing in the middle of the ocean,” said co-author Tristan Smith from UCL Energy Institute. “The potential for undetected non-compliance with the 2020 sulfur regulations is a real risk for shipping companies because it can create commercial advantage to those companies who do not comply. This study shows that science and technology are producing significant advancements in the transparency of shipping and helping to reduce risks and unfairness for responsible operators.”

The paper “The impact of ship emission controls recorded by cloud properties” has been published in Geophysical Research Letters. It was published by researchers from Imperial College London, together with University College London (UCL) and the University of Oxford: Edward Gryspeerdt, Tristan Smith, Eoin O’Keeffe, Matthew Christensen and Fraser Goldsworth.