Preprints
https://doi.org/10.5194/egusphere-2022-1102
https://doi.org/10.5194/egusphere-2022-1102
28 Oct 2022
 | 28 Oct 2022

Indian Ocean variability changes in the Palaeoclimate Model Intercomparison Project

Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley

Abstract. The Indian Ocean exhibits multiple modes of interannual climate variability, whose future behaviour is uncertain. Recent analysis of glacial climates has uncovered an additional El Niño-like equatorial mode in the Indian Ocean, which could also emerge in future warm states. Here we explore changes in the tropical Indian Ocean simulated by the Palaeoclimate Model Intercomparison Project (PMIP4). These simulations are performed by an ensemble of models contributing to the Coupled Model Intercomparison Project 6, and over four coordinated experiments: three past periods - the mid-Holocene (6000 years5 ago), the last glacial maximum (21,000 years ago), the last interglacial (127,000 years ago) - and an idealised forcing scenario to examine the impact of greenhouse forcing. The two interglacial experiments are used to characterise the role of orbital variations on the seasonal cycle, whilst the other pair focus on responses to large changes in global temperature.

The Indian Ocean Basin Mode (IOBM) is damped in both the mid-Holocene and last interglacial, with the amount related to the damping of the El Niño-Southern Oscillation in the Pacific. No coherent changes in the strength of the IOBM are seen10 with global temperature changes; neither are changes in the Indian Ocean Dipole (IOD) nor the Niño-like mode. Under orbital forcing, the IOD robustly weakens during the mid-Holocene experiment, with only minor reductions in amplitude during the last interglacial. Orbital changes do impact the SST pattern of the Indian Ocean Dipole, with the cold pole reaching up to the Equator and extending along it. Induced changes in the regional seasonality are hypothesised to be important control on changes in the Indian Ocean variability.

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 preprint. The responsibility to include appropriate place names lies with the authors.

Journal article(s) based on this preprint

27 Mar 2023
Indian Ocean variability changes in the Paleoclimate Modelling Intercomparison Project
Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley
Clim. Past, 19, 681–701, https://doi.org/10.5194/cp-19-681-2023,https://doi.org/10.5194/cp-19-681-2023, 2023
Short summary
Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1102', Anonymous Referee #1, 06 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • RC2: 'Comment on egusphere-2022-1102', Anonymous Referee #2, 12 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • RC3: 'Comment on egusphere-2022-1102', Mehdi Pasha Karami, 23 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023

Interactive discussion

Status: closed

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2022-1102', Anonymous Referee #1, 06 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • RC2: 'Comment on egusphere-2022-1102', Anonymous Referee #2, 12 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • RC3: 'Comment on egusphere-2022-1102', Mehdi Pasha Karami, 23 Dec 2022
    • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023
  • AC1: 'Combined response to all reviews', Chris Brierley, 04 Jan 2023

Peer review completion

AR: Author's response | RR: Referee report | ED: Editor decision | EF: Editorial file upload
ED: Publish subject to minor revisions (review by editor) (17 Jan 2023) by Qiuzhen Yin
AR by Chris Brierley on behalf of the Authors (17 Jan 2023)  Author's response   Author's tracked changes   Manuscript 
ED: Publish as is (23 Jan 2023) by Qiuzhen Yin
AR by Chris Brierley on behalf of the Authors (30 Jan 2023)  Author's response   Manuscript 

Post-review adjustments

AA: Author's adjustment | EA: Editor approval
AA by Chris Brierley on behalf of the Authors (23 Feb 2023)   Author's adjustment   Manuscript
EA: Adjustments approved (24 Feb 2023) by Qiuzhen Yin

Journal article(s) based on this preprint

27 Mar 2023
Indian Ocean variability changes in the Paleoclimate Modelling Intercomparison Project
Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley
Clim. Past, 19, 681–701, https://doi.org/10.5194/cp-19-681-2023,https://doi.org/10.5194/cp-19-681-2023, 2023
Short summary
Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley

Model code and software

Indiabn Ocean Variability repository on GitHub Chris Brierley, Kau Thirulamai https://github.com/pmip4/IndianOceanVariability

Chris Brierley, Kaustubh Thirumalai, Edward Grindrod, and Jonathan Barnsley

Viewed

Total article views: 500 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
354 129 17 500 6 6
  • HTML: 354
  • PDF: 129
  • XML: 17
  • Total: 500
  • BibTeX: 6
  • EndNote: 6
Views and downloads (calculated since 28 Oct 2022)
Cumulative views and downloads (calculated since 28 Oct 2022)

Viewed (geographical distribution)

Total article views: 508 (including HTML, PDF, and XML) Thereof 508 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 
Latest update: 02 Sep 2024
Download

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

Short summary
Year-to-year variations in the weather conditions over the Indian Ocean have important consequences for the substantial fraction of the Earth's population that live near it. This work looks at how these variations respond to climate change - both past and future. The models rarely agree, suggesting a weak, uncertain response to climate change.