Global Reduction in Ship-tracks from Sulfur Regulations for Shipping Fuel

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2206.05382.pdf (4.92 MB)

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https://arxiv.org/abs/2206.05382

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https://doi.org/10.48550/arXiv.2206.05382
 http://hdl.handle.net/11603/25168

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UMBC Joint Center for Earth Systems Technology (JCET)
UMBC Faculty Collection

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Author/Creator ORCID

https://orcid.org/0000-0002-2187-3017
 https://orcid.org/0000-0001-5136-1322

Date

2022-06-11

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journal articles
preprints
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This work was written as part of one of the author's official duties as an Employee of the United States Government and is therefore a work of the United States Government. In accordance with 17 U.S.C. 105, no copyright protection is available for such works under U.S. Law.
Public Domain Mark 1.0

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Abstract

Ship-tracks are produced by ship-emitted aerosols interacting with marine low clouds. Here we apply deep learning models on satellite data to produce the first multi-year global climatology map of ship-tracks. We show that ship-tracks are at the nexus of cloud physics, maritime shipping, and fuel regulation. Our map captures major shipping lanes while missing others, reflecting the influences of background cloud and aerosol properties. Ship-track frequency is more than 10 times higher than expected from a previous survey. Interannual fluctuations in ship-track frequency reflect variations in cross-ocean trade, shipping activity, and fuel regulations. Fuel regulation can alter both detected ship-track density and pattern of shipping routes due to cost economics. The new fuel regulation, together with the COVID-19 pandemic, reduced ship-track frequency in 2020 to its lowest level in recent decades across the globe and may have ushered in a new era of low ship-track frequency. We estimate the aerosol indirect forcing induced by the fuel regulation to be between 0.02 and 0.22 Wm-2.