Changes to the tropical circulation in the mid-Pliocene and their implications for future climate
The two components of the tropical overturning circulation, the meridional Hadley circulation (HC) and the zonal Walker circulation (WC), are key to the re-distribution of moisture, heat and mass in the atmosphere. The mid-Pliocene Warm Period (mPWP; ∼ 3.3–3 Ma) is considered a very rough analogue o...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
| Published: |
Copernicus Publications
2017-02-01
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| Series: | Climate of the Past |
| Online Access: | http://www.clim-past.net/13/135/2017/cp-13-135-2017.pdf |
| _version_ | 1811219599477178368 |
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| author | S. Corvec C. G. Fletcher |
| author_facet | S. Corvec C. G. Fletcher |
| author_sort | S. Corvec |
| collection | DOAJ |
| description | The two components of the tropical overturning circulation, the meridional
Hadley circulation (HC) and the zonal Walker circulation (WC), are key to the
re-distribution of moisture, heat and mass in the atmosphere. The
mid-Pliocene Warm Period (mPWP; ∼ 3.3–3 Ma) is considered a very
rough analogue of near-term future climate change, yet changes to the
tropical overturning circulations in the mPWP are poorly understood. Here,
climate model simulations from the Pliocene Model Intercomparison Project
(PlioMIP) are analyzed to show that the tropical overturning circulations in
the mPWP were weaker than preindustrial circulations, just as they are projected to be in
future climate change. The weakening HC response is consistent with future
projections, and its strength is strongly related to the meridional gradient
of sea surface warming between the tropical and subtropical oceans. The
weakening of the WC is less robust in PlioMIP than in future projections,
largely due to inter-model variations in simulated warming of the tropical
Indian Ocean (TIO). When the TIO warms faster (slower) than the tropical
mean, local upper tropospheric divergence increases (decreases) and the WC
weakens less (more). These results provide strong evidence that changes to
the tropical overturning circulation in the mPWP and future climate are
primarily controlled by zonal (WC) and meridional (HC) gradients in
tropical–subtropical sea surface temperatures. |
| first_indexed | 2024-04-12T07:29:28Z |
| format | Article |
| id | doaj.art-a37e708ece964cb19979f8db2ee125e7 |
| institution | Directory Open Access Journal |
| issn | 1814-9324 1814-9332 |
| language | English |
| last_indexed | 2024-04-12T07:29:28Z |
| publishDate | 2017-02-01 |
| publisher | Copernicus Publications |
| record_format | Article |
| series | Climate of the Past |
| spelling | doaj.art-a37e708ece964cb19979f8db2ee125e72022-12-22T03:42:06ZengCopernicus PublicationsClimate of the Past1814-93241814-93322017-02-0113213514710.5194/cp-13-135-2017Changes to the tropical circulation in the mid-Pliocene and their implications for future climateS. Corvec0C. G. Fletcher1Department of Applied Mathematics, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, CanadaDepartment of Geography and Environmental Management, University of Waterloo, 200 University Ave W, Waterloo, Ontario, N2L 3G1, CanadaThe two components of the tropical overturning circulation, the meridional Hadley circulation (HC) and the zonal Walker circulation (WC), are key to the re-distribution of moisture, heat and mass in the atmosphere. The mid-Pliocene Warm Period (mPWP; ∼ 3.3–3 Ma) is considered a very rough analogue of near-term future climate change, yet changes to the tropical overturning circulations in the mPWP are poorly understood. Here, climate model simulations from the Pliocene Model Intercomparison Project (PlioMIP) are analyzed to show that the tropical overturning circulations in the mPWP were weaker than preindustrial circulations, just as they are projected to be in future climate change. The weakening HC response is consistent with future projections, and its strength is strongly related to the meridional gradient of sea surface warming between the tropical and subtropical oceans. The weakening of the WC is less robust in PlioMIP than in future projections, largely due to inter-model variations in simulated warming of the tropical Indian Ocean (TIO). When the TIO warms faster (slower) than the tropical mean, local upper tropospheric divergence increases (decreases) and the WC weakens less (more). These results provide strong evidence that changes to the tropical overturning circulation in the mPWP and future climate are primarily controlled by zonal (WC) and meridional (HC) gradients in tropical–subtropical sea surface temperatures.http://www.clim-past.net/13/135/2017/cp-13-135-2017.pdf |
| spellingShingle | S. Corvec C. G. Fletcher Changes to the tropical circulation in the mid-Pliocene and their implications for future climate Climate of the Past |
| title | Changes to the tropical circulation in the mid-Pliocene and their implications for future climate |
| title_full | Changes to the tropical circulation in the mid-Pliocene and their implications for future climate |
| title_fullStr | Changes to the tropical circulation in the mid-Pliocene and their implications for future climate |
| title_full_unstemmed | Changes to the tropical circulation in the mid-Pliocene and their implications for future climate |
| title_short | Changes to the tropical circulation in the mid-Pliocene and their implications for future climate |
| title_sort | changes to the tropical circulation in the mid pliocene and their implications for future climate |
| url | http://www.clim-past.net/13/135/2017/cp-13-135-2017.pdf |
| work_keys_str_mv | AT scorvec changestothetropicalcirculationinthemidplioceneandtheirimplicationsforfutureclimate AT cgfletcher changestothetropicalcirculationinthemidplioceneandtheirimplicationsforfutureclimate |