Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Climate sensitivity and meridional overturning circulation in the late Eocene using GFDL CM2.1
Stockholm University, Faculty of Science, Department of Geological Sciences.ORCID iD: 0000-0001-9385-4782
Stockholm University, Faculty of Science, Department of Geological Sciences.
Stockholm University, Faculty of Science, Department of Geological Sciences.
Stockholm University, Faculty of Science, Department of Meteorology .ORCID iD: 0000-0002-5507-9209
Show others and affiliations
Number of Authors: 62018 (English)In: Climate of the Past, ISSN 1814-9324, E-ISSN 1814-9332, Vol. 14, no 6, p. 789-810Article in journal (Refereed) Published
Abstract [en]

The Eocene-Oligocene transition (EOT), which took place approximately 34 Ma ago, is an interval of great interest in Earth's climate history, due to the inception of the Antarctic ice sheet and major global cooling. Climate simulations of the transition are needed to help interpret proxy data, test mechanistic hypotheses for the transition and determine the climate sensitivity at the time. However, model studies of the EOT thus far typically employ control states designed for a different time period, or ocean resolution on the order of 3 degrees. Here we developed a new higher resolution palaeoclimate model configuration based on the GFDL CM2.1 climate model adapted to a late Eocene (38 Ma) palaeogeography reconstruction. The ocean and atmosphere horizontal resolutions are 1 degrees similar to 1.5 degrees and 3 degrees 3.75 ffi respectively. This represents a significant step forward in resolving the ocean geography, gateways and circulation in a coupled climate model of this period. We run the model under three different levels of atmospheric CO2: 400, 800 and 1600 ppm. The model exhibits relatively high sensitivity to CO2 compared with other recent model studies, and thus can capture the expected Eocene high latitude warmth within observed estimates of atmospheric CO2. However, the model does not capture the low meridional temperature gradient seen in proxies. Equatorial sea surface temperatures are too high in the model (3037 degrees C) compared with observations (max 32 degrees C), although observations are lacking in the warmest regions of the western Pacific. The model exhibits bipolar sinking in the North Pacific and Southern Ocean, which persists under all levels of CO2. North Atlantic surface salinities are too fresh to permit sinking (25-30 psu), due to surface transport from the very fresh Arctic (similar to 20 psu), where surface salinities approximately agree with Eocene proxy estimates. North Atlantic salinity increases by 1-2 psu when CO2 is halved, and similarly freshens when CO2 is doubled, due to changes in the hydrological cycle.

Place, publisher, year, edition, pages
2018. Vol. 14, no 6, p. 789-810
National Category
Earth and Related Environmental Sciences
Identifiers
URN: urn:nbn:se:su:diva-158265DOI: 10.5194/cp-14-789-2018ISI: 000435187700001OAI: oai:DiVA.org:su-158265DiVA, id: diva2:1236633
Available from: 2018-08-03 Created: 2018-08-03 Last updated: 2018-08-03Bibliographically approved

Open Access in DiVA

No full text in DiVA

Other links

Publisher's full text

Search in DiVA

By author/editor
Hutchinson, David K.de Boer, Agatha M.Coxall, Helen K.Caballero, RodrigoNilsson, Johan
By organisation
Department of Geological SciencesDepartment of Meteorology
In the same journal
Climate of the Past
Earth and Related Environmental Sciences

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 11 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf