Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks
Low-resolution, complex general circulation models (GCMs) are valuable tools for studying the Earth system on multi-millennial timescales. However, slowly evolving salinity drifts can cause large shifts in climatic and oceanic regimes over thousands of years. We test two different schemes for neutra...
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ftunivreading:oai:centaur.reading.ac.uk:81239 2024-05-19T07:44:54+00:00 Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks Dentith, Jennifer E. Ivanovic, Ruza F. Gregoire, Lauren J. Tindall, Julia C. Smith, Robin 2019-02 text https://centaur.reading.ac.uk/81239/ https://centaur.reading.ac.uk/81239/1/Dentith2018_Article_OceanCirculationDriftsInMulti-.pdf en eng Springer https://centaur.reading.ac.uk/81239/1/Dentith2018_Article_OceanCirculationDriftsInMulti-.pdf Dentith, J. E., Ivanovic, R. F., Gregoire, L. J., Tindall, J. C. and Smith, R. <https://centaur.reading.ac.uk/view/creators/90000556.html> orcid:0000-0001-7479-7778 (2019) Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks. Climate Dynamics, 52 (3-4). pp. 1761-1781. ISSN 0930-7575 doi: https://doi.org/10.1007/s00382-018-4243-y <https://doi.org/10.1007/s00382-018-4243-y> cc_by_4 Article PeerReviewed 2019 ftunivreading https://doi.org/10.1007/s00382-018-4243-y 2024-05-01T00:18:57Z Low-resolution, complex general circulation models (GCMs) are valuable tools for studying the Earth system on multi-millennial timescales. However, slowly evolving salinity drifts can cause large shifts in climatic and oceanic regimes over thousands of years. We test two different schemes for neutralising unforced salinity drifts in the FAMOUS GCM: surface flux correction and volumetric flux correction. Although both methods successfully maintain a steady global mean salinity, local drifts and subsequent feedbacks promote cooling (≈ 4 °C over 6000 years) and freshening (≈ 2 psu over 6000 years) in the North Atlantic Ocean, and gradual warming (≈ 0.2 °C per millennium) and salinification (≈ 0.15 psu per millennium) in the North Pacific Ocean. Changes in the surface density in these regions affect the meridional overturning circulation (MOC), such that, after several millennia, the Atlantic MOC (AMOC) is in a collapsed state, and there is a strong, deep Pacific MOC (PMOC). Furthermore, the AMOC exhibits a period of metastability, which is only identifiable with run lengths in excess of 1500 years. We also compare simulations with two different land surface schemes, demonstrating that small biases in the surface climate may cause regional salinity drifts and significant shifts in the MOC (weakening of the AMOC and the initiation then invigoration of PMOC), even when the global hydrological cycle has been forcibly closed. Although there is no specific precursor to the simulated AMOC collapse, the northwest North Pacific and northeast North Atlantic are important areas that should be closely monitored for trends arising from such biases. Article in Journal/Newspaper North Atlantic CentAUR: Central Archive at the University of Reading Climate Dynamics 52 3-4 1761 1781 |
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Open Polar |
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CentAUR: Central Archive at the University of Reading |
op_collection_id |
ftunivreading |
language |
English |
description |
Low-resolution, complex general circulation models (GCMs) are valuable tools for studying the Earth system on multi-millennial timescales. However, slowly evolving salinity drifts can cause large shifts in climatic and oceanic regimes over thousands of years. We test two different schemes for neutralising unforced salinity drifts in the FAMOUS GCM: surface flux correction and volumetric flux correction. Although both methods successfully maintain a steady global mean salinity, local drifts and subsequent feedbacks promote cooling (≈ 4 °C over 6000 years) and freshening (≈ 2 psu over 6000 years) in the North Atlantic Ocean, and gradual warming (≈ 0.2 °C per millennium) and salinification (≈ 0.15 psu per millennium) in the North Pacific Ocean. Changes in the surface density in these regions affect the meridional overturning circulation (MOC), such that, after several millennia, the Atlantic MOC (AMOC) is in a collapsed state, and there is a strong, deep Pacific MOC (PMOC). Furthermore, the AMOC exhibits a period of metastability, which is only identifiable with run lengths in excess of 1500 years. We also compare simulations with two different land surface schemes, demonstrating that small biases in the surface climate may cause regional salinity drifts and significant shifts in the MOC (weakening of the AMOC and the initiation then invigoration of PMOC), even when the global hydrological cycle has been forcibly closed. Although there is no specific precursor to the simulated AMOC collapse, the northwest North Pacific and northeast North Atlantic are important areas that should be closely monitored for trends arising from such biases. |
format |
Article in Journal/Newspaper |
author |
Dentith, Jennifer E. Ivanovic, Ruza F. Gregoire, Lauren J. Tindall, Julia C. Smith, Robin |
spellingShingle |
Dentith, Jennifer E. Ivanovic, Ruza F. Gregoire, Lauren J. Tindall, Julia C. Smith, Robin Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
author_facet |
Dentith, Jennifer E. Ivanovic, Ruza F. Gregoire, Lauren J. Tindall, Julia C. Smith, Robin |
author_sort |
Dentith, Jennifer E. |
title |
Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
title_short |
Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
title_full |
Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
title_fullStr |
Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
title_full_unstemmed |
Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
title_sort |
ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks |
publisher |
Springer |
publishDate |
2019 |
url |
https://centaur.reading.ac.uk/81239/ https://centaur.reading.ac.uk/81239/1/Dentith2018_Article_OceanCirculationDriftsInMulti-.pdf |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://centaur.reading.ac.uk/81239/1/Dentith2018_Article_OceanCirculationDriftsInMulti-.pdf Dentith, J. E., Ivanovic, R. F., Gregoire, L. J., Tindall, J. C. and Smith, R. <https://centaur.reading.ac.uk/view/creators/90000556.html> orcid:0000-0001-7479-7778 (2019) Ocean circulation drifts in multi-millennial climate simulations: the role of salinity corrections and climate feedbacks. Climate Dynamics, 52 (3-4). pp. 1761-1781. ISSN 0930-7575 doi: https://doi.org/10.1007/s00382-018-4243-y <https://doi.org/10.1007/s00382-018-4243-y> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1007/s00382-018-4243-y |
container_title |
Climate Dynamics |
container_volume |
52 |
container_issue |
3-4 |
container_start_page |
1761 |
op_container_end_page |
1781 |
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1799484789906997248 |