Journal cover Journal topic
Earth System Dynamics An interactive open-access journal of the European Geosciences Union
Journal topic

Journal metrics

Journal metrics

  • IF value: 3.866 IF 3.866
  • IF 5-year value: 4.135 IF 5-year
    4.135
  • CiteScore value: 7.0 CiteScore
    7.0
  • SNIP value: 1.182 SNIP 1.182
  • IPP value: 3.86 IPP 3.86
  • SJR value: 1.883 SJR 1.883
  • Scimago H <br class='hide-on-tablet hide-on-mobile'>index value: 33 Scimago H
    index 33
  • h5-index value: 30 h5-index 30
Preprints
https://doi.org/10.5194/esd-2020-30
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.
https://doi.org/10.5194/esd-2020-30
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Submitted as: research article 29 Jun 2020

Submitted as: research article | 29 Jun 2020

Review status
This preprint is currently under review for the journal ESD.

Effect of changing ocean circulation on deep ocean temperature in the last millennium

Jeemijn Scheen1,2 and Thomas F. Stocker1,2 Jeemijn Scheen and Thomas F. Stocker
  • 1Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland
  • 2Oeschger Centre for Climate Change Research, University of Bern, Bern, Switzerland

Abstract. Paleoreconstructions and modern observations provide us with anomalies of surface temperature over the past millennium. The history of deep ocean temperatures is much less well-known and was simulated in a recent study for the past 2000 years under forced surface temperature anomalies. In this study, we simulate the past 800 years with an illustrative forcing scenario in the Bern3D ocean model, which enables us to assess the role of changes in ocean circulation on deep ocean temperature. We quantify the effect of changing ocean circulation by comparing transient simulations (where the ocean dynamically adjusts to anomalies in surface temperature – hence density) to simulations with fixed ocean circulation. We decompose temperature, ocean heat content and meridional heat transport into the contributions from changing ocean circulation and changing sea surface temperature (SST). In the deep ocean, the contribution from changing ocean circulation is found to be as important as the changing SST signal itself. Firstly, the small changes in ocean circulation amplify the Little Ice Age signal around 3 km depth by at least a factor of two, depending on the basin. Secondly, they fasten the arrival of this atmospheric signal in the Pacific and Southern Ocean at all depths, whereas they delay the arrival in the Atlantic between about 2.5 and 3.5 km by two centuries. This delay is explained by an initial competition between the Little Ice Age cooling and a warming due to an increase in relatively warmer North Atlantic Deep Water at the cost of Antarctic Bottom Water. Under the consecutive AMOC slowdown, this shift in water masses is inverted and aging of the water causes a late additional cooling. Our results suggest that small changes in ocean circulation can have a large impact on the amplitude and timing of ocean temperature anomalies below 2 km depth.

Jeemijn Scheen and Thomas F. Stocker

Interactive discussion

Status: open (until 10 Aug 2020)
Status: open (until 10 Aug 2020)
AC: Author comment | RC: Referee comment | SC: Short comment | EC: Editor comment
[Subscribe to comment alert] Printer-friendly Version - Printer-friendly version Supplement - Supplement

Jeemijn Scheen and Thomas F. Stocker

Data sets

Effect of changing ocean circulation on deep ocean temperature in the last millennium: simulation output data J. Scheen and T. F. Stocker https://doi.org/10.5281/zenodo.3878835

Model code and software

Effect of changing ocean circulation on deep ocean temperature in the last millennium: code J. Scheen https://doi.org/10.5281/zenodo.3909580

Jeemijn Scheen and Thomas F. Stocker

Viewed

Total article views: 35 (including HTML, PDF, and XML)
HTML PDF XML Total BibTeX EndNote
15 18 2 35 2 2
  • HTML: 15
  • PDF: 18
  • XML: 2
  • Total: 35
  • BibTeX: 2
  • EndNote: 2
Views and downloads (calculated since 29 Jun 2020)
Cumulative views and downloads (calculated since 29 Jun 2020)

Viewed (geographical distribution)

Total article views: 49 (including HTML, PDF, and XML) Thereof 49 with geography defined and 0 with unknown origin.
Country # Views %
  • 1
1
 
 
 
 

Cited

Saved

No saved metrics found.

Discussed

No discussed metrics found.
Latest update: 08 Jul 2020
Publications Copernicus
Download
Short summary
Variability of sea surface temperatures (SST) from 1200 to 2000 CE is quite well-known, but the history of deep ocean temperatures is not. Forcing an ocean model with these SSTs, we simulate temperatures in the ocean interior. The circulation changes alter amplitude and timing of deep ocean temperature fluctuations below 2 km depth, e.g., delay the atmospheric signal by ~ 200 yr in the deep Atlantic. Therefore, ocean circulation changes are shown to be as important as SST changes at these depths.
Variability of sea surface temperatures (SST) from 1200 to 2000 CE is quite well-known, but the...
Citation