Preprints
https://doi.org/10.5194/egusphere-2024-3229
https://doi.org/10.5194/egusphere-2024-3229
04 Nov 2024
 | 04 Nov 2024

Adjustments to an abrupt solar forcing in the CMIP6 abrupt-solm4p experiment

Charlotte Lange and Johannes Quaas

Abstract. The concept of "radiative" or "rapid" adjustments refers to the response of the climate system to an instantaneous radiative forcing, independent of surface temperature changes. These adjustments can occur over time scales from hours (e.g. aerosol-cloud-interactions) to months (e.g. stratospheric temperature changes) or even longer, making it challenging to distinguish adjustments from feedbacks over longer time scales. Despite variations in definitions, understanding these processes is essential for advancing climate modeling.

Strong volcanic eruptions, which produce scattering aerosol layers in the stratosphere, offer natural experiments to study short-term adjustments. However, the gradual spread of aerosols over the globe over months complicates analysis, requiring more controlled experiments. The abrupt-solm4p experiment within the Cloud Feedback Model Intercomparison Project (CFMIP) as part of the 6th Coupled Model Intercomparison Project (CMIP6) simulates an instantaneous 4 % reduction in the solar constant, starting from a pre-industrial run on 1 January 1850. This study analyzed changes in climate variables, cloud properties, and radiative fluxes over different time scales (hours, days, months and up to 150 years) to understand adjustment processes.

Four models were evaluated, showing initial rapid cooling, particularly over Antarctica and the southern hemisphere, slowing down the polar night jet, disrupting the polar vortex and increasing Arctic cloud cover. During the first month, the troposphere cools down faster than the ocean surface, decreasing vertical stability and increasing cloud cover over ocean, while the opposite effect happens in the tropics over land. This in turn affects land-sea-circulation. On longer time scales we find robust changes of cloudiness.

Competing interests: Johannes Quaas is a member of the editorial board of Atmospheric Chemistry and Physics

Publisher's note: Copernicus Publications remains neutral with regard to jurisdictional claims made in the text, published maps, institutional affiliations, or any other geographical representation in this paper. While Copernicus Publications makes every effort to include appropriate place names, the final responsibility lies with the authors. Views expressed in the text are those of the authors and do not necessarily reflect the views of the publisher.
Share

Journal article(s) based on this preprint

11 Sep 2025
Adjustments to an abrupt solar forcing in the CMIP6 abrupt-solm4p experiment
Charlotte Lange and Johannes Quaas
Atmos. Chem. Phys., 25, 10337–10359, https://doi.org/10.5194/acp-25-10337-2025,https://doi.org/10.5194/acp-25-10337-2025, 2025
Short summary
Charlotte Lange and Johannes Quaas

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-3229', Anonymous Referee #1, 25 Nov 2024
    • AC1: 'Reply on RC1', Charlotte Lange, 06 Mar 2025
  • RC2: 'Comment on egusphere-2024-3229', Anonymous Referee #2, 26 Jan 2025
    • AC2: 'Reply on RC2', Charlotte Lange, 06 Mar 2025

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2024-3229', Anonymous Referee #1, 25 Nov 2024
    • AC1: 'Reply on RC1', Charlotte Lange, 06 Mar 2025
  • RC2: 'Comment on egusphere-2024-3229', Anonymous Referee #2, 26 Jan 2025
    • AC2: 'Reply on RC2', Charlotte Lange, 06 Mar 2025

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
AR by Charlotte Lange on behalf of the Authors (19 Mar 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Referee Nomination & Report Request started (09 Apr 2025) by Aurélien Podglajen
RR by Anonymous Referee #3 (25 Apr 2025)
RR by Anonymous Referee #4 (06 May 2025)
ED: Reconsider after major revisions (06 May 2025) by Aurélien Podglajen
AR by Charlotte Lange on behalf of the Authors (17 Jun 2025)  Author's response   Author's tracked changes   Manuscript 
ED: Publish subject to technical corrections (18 Jun 2025) by Aurélien Podglajen
AR by Charlotte Lange on behalf of the Authors (20 Jun 2025)  Author's response   Manuscript 

Journal article(s) based on this preprint

11 Sep 2025
Adjustments to an abrupt solar forcing in the CMIP6 abrupt-solm4p experiment
Charlotte Lange and Johannes Quaas
Atmos. Chem. Phys., 25, 10337–10359, https://doi.org/10.5194/acp-25-10337-2025,https://doi.org/10.5194/acp-25-10337-2025, 2025
Short summary
Charlotte Lange and Johannes Quaas
Charlotte Lange and Johannes Quaas

Viewed

Total article views: 968 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
710 131 127 968 34 44
  • HTML: 710
  • PDF: 131
  • XML: 127
  • Total: 968
  • BibTeX: 34
  • EndNote: 44
Views and downloads (calculated since 04 Nov 2024)
Cumulative views and downloads (calculated since 04 Nov 2024)

Viewed (geographical distribution)

Total article views: 960 (including HTML, PDF, and XML) Thereof 960 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 11 Sep 2025
Download

The requested preprint has a corresponding peer-reviewed final revised paper. You are encouraged to refer to the final revised version.

Short summary
We studied how the Earth’s climate system adjusts to sudden changes in the energy budget, by analyzing data of four climate models, which simulated a 4 % reduction of incoming solar energy. We found rapid cooling of the atmosphere and shifts in cloud cover and atmospheric circulation patterns like land-sea-circulation. Our research helps to better understand cloud adjustments, which are a main source of uncertainty in climate models. This can improve future climate predictions.
Share