Preprints
https://doi.org/10.5194/egusphere-2023-971
https://doi.org/10.5194/egusphere-2023-971
22 May 2023
 | 22 May 2023
Status: this preprint is open for discussion and under review for Atmospheric Chemistry and Physics (ACP).

Detection of large-scale cloud microphysical changes and evidence for decreasing cloud brightness within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations

Michael Steven Diamond

Abstract. New regulations from the International Maritime Organization (IMO) limiting sulfur emissions from the shipping industry are expected to have large benefits in terms of public health but come with an undesired side effect: an acceleration of global warming as the climate-cooling effects of ship pollution on marine clouds is diminished. Previous work has found a substantial decrease in the detection of ship tracks in clouds after the IMO 2020 regulations went into effect but changes in large-scale cloud properties have been more equivocal. Using a statistical technique that estimates counterfactual fields of what large-scale cloud and radiative properties within an isolated shipping corridor in the southeastern Atlantic would have been in the absence of shipping, we confidently detect a reduction in the magnitude of cloud droplet effective radius decreases within the shipping corridor and find evidence for a reduction in the magnitude of cloud brightening as well. The instantaneous radiative forcing due to aerosol–cloud interactions from the IMO 2020 regulations is estimated as O(1 W m-2) within the shipping corridor, lending credence to global estimates of O(0.1 W m-2). In addition to their geophysical significance, our results also provide independent evidence for general compliance with the IMO 2020 regulations.

Michael Steven Diamond

Status: open (until 21 Jun 2023)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse

Michael Steven Diamond

Data sets

Data for "Detection of large-scale cloud microphysical changes and evidence for decreasing cloud brightness within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations" Michael S. Diamond https://doi.org/10.5281/zenodo.7864530

Model code and software

Code for "Detection of large-scale cloud microphysical changes and evidence for decreasing cloud brightness within a major shipping corridor after implementation of the International Maritime Organization 2020 fuel sulfur regulations" Michael S. Diamond https://github.com/michael-s-diamond/IMO2020

Michael Steven Diamond

Viewed

Total article views: 330 (including HTML, PDF, and XML)
HTML PDF XML Total Supplement BibTeX EndNote
241 81 8 330 20 3 3
  • HTML: 241
  • PDF: 81
  • XML: 8
  • Total: 330
  • Supplement: 20
  • BibTeX: 3
  • EndNote: 3
Views and downloads (calculated since 22 May 2023)
Cumulative views and downloads (calculated since 22 May 2023)

Viewed (geographical distribution)

Total article views: 366 (including HTML, PDF, and XML) Thereof 366 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 04 Jun 2023
Download
Short summary
Fuel sulfur regulations were implemented for ships in 2020 to improve air quality but may also accelerate global warming. We use spatial statistics and satellite retrievals to detect changes in the size of cloud droplets and find evidence for a resulting decrease in cloud brightness within a major shipping corridor after the sulfur limits went into effect. Our results confirm both that the regulations are being followed and that they are having a warming influence via their effect on clouds.