Articles | Volume 23, issue 19
ACP Letters
 | Highlight paper
09 Oct 2023
ACP Letters | Highlight paper |  | 09 Oct 2023

Rapid saturation of cloud water adjustments to shipping emissions

Peter Manshausen, Duncan Watson-Parris, Matthew W. Christensen, Jukka-Pekka Jalkanen, and Philip Stier


Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-813', Anonymous Referee #1, 29 May 2023
  • RC2: 'Comment on egusphere-2023-813', Anonymous Referee #2, 16 Jun 2023
  • AC1: 'Comment on egusphere-2023-813', Peter Manshausen, 19 Jul 2023

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Peter Manshausen on behalf of the Authors (19 Jul 2023)  Author's response   Manuscript 
EF by Lorena Grabowski (20 Jul 2023)  Author's tracked changes 
ED: Referee Nomination & Report Request started (28 Jul 2023) by Martina Krämer
RR by Anonymous Referee #1 (29 Jul 2023)
RR by Anonymous Referee #2 (31 Jul 2023)
ED: Publish subject to technical corrections (15 Aug 2023) by Martina Krämer
ED: Publish as is (18 Aug 2023) by Timothy Garrett (Executive editor)
AR by Peter Manshausen on behalf of the Authors (01 Sep 2023)  Manuscript 
Executive editor
Ship tracks are enhanced regions of cloud brightness that trail behind ships that are known to be created by their effluent. They are widely used as observational test beds to deepen understanding of how pollution might affect cloud microphysical processes and climate at larger regional and global scales.  This study uses satellite observations of cloud properties and records of ship position and their effluent to assess perturbations from ship emissions on cloud droplet number and liquid water path. The study found that, as expected, the droplet number perturbation in shiptracks scales with ship emission rates of aerosol particles. Surprisingly, however, the liquid water path in drizzling clouds increased by an amount that was nearly fixed. The observation points to novel non-linear threshold behaviours of relevance to representations of aerosol indirect effects in climate models.
Short summary
Aerosol from burning fuel changes cloud properties, e.g., the number of droplets and the content of water. Here, we study how clouds respond to different amounts of shipping aerosol. Droplet numbers increase linearly with increasing aerosol over a broad range until they stop increasing, while the amount of liquid water always increases, independently of emission amount. These changes in cloud properties can make them reflect more or less sunlight, which is important for the earth's climate.
Final-revised paper