The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone
Through study of observations and coupled climate simulations, it is argued that the mean position of the Inter-Tropical Convergence Zone (ITCZ) north of the equator is a consequence of a northwards heat transport across the equator by ocean circulation. Observations suggest that the hemispheric net...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | en_US |
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Springer-Verlag
2014
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| Online Access: | http://hdl.handle.net/1721.1/85592 https://orcid.org/0000-0001-9230-3591 |
| _version_ | 1811078070908485632 |
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| author | Donohoe, Aaron Ferreira, David Marshall, John C McGee, William David |
| author2 | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences |
| author_facet | Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Donohoe, Aaron Ferreira, David Marshall, John C McGee, William David |
| author_sort | Donohoe, Aaron |
| collection | MIT |
| description | Through study of observations and coupled climate simulations, it is argued that the mean position of the Inter-Tropical Convergence Zone (ITCZ) north of the equator is a consequence of a northwards heat transport across the equator by ocean circulation. Observations suggest that the hemispheric net radiative forcing of climate at the top of the atmosphere is almost perfectly symmetric about the equator, and so the total (atmosphere plus ocean) heat transport across the equator is small (order 0.2 PW northwards). Due to the Atlantic ocean’s meridional overturning circulation, however, the ocean carries significantly more heat northwards across the equator (order 0.4 PW) than does the coupled system. There are two primary consequences. First, atmospheric heat transport is southwards across the equator to compensate (0.2 PW southwards), resulting in the ITCZ being displaced north of the equator. Second, the atmosphere, and indeed the ocean, is slightly warmer (by perhaps 2 °C) in the northern hemisphere than in the southern hemisphere. This leads to the northern hemisphere emitting slightly more outgoing longwave radiation than the southern hemisphere by virtue of its relative warmth, supporting the small northward heat transport by the coupled system across the equator. To conclude, the coupled nature of the problem is illustrated through study of atmosphere–ocean–ice simulations in the idealized setting of an aquaplanet, resolving the key processes at work. |
| first_indexed | 2024-09-23T10:52:55Z |
| format | Article |
| id | mit-1721.1/85592 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T10:52:55Z |
| publishDate | 2014 |
| publisher | Springer-Verlag |
| record_format | dspace |
| spelling | mit-1721.1/855922024-05-15T02:21:47Z The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone Donohoe, Aaron Ferreira, David Marshall, John C McGee, William David Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences Marshall, John C. Donohoe, Aaron Ferreira, David McGee, David Through study of observations and coupled climate simulations, it is argued that the mean position of the Inter-Tropical Convergence Zone (ITCZ) north of the equator is a consequence of a northwards heat transport across the equator by ocean circulation. Observations suggest that the hemispheric net radiative forcing of climate at the top of the atmosphere is almost perfectly symmetric about the equator, and so the total (atmosphere plus ocean) heat transport across the equator is small (order 0.2 PW northwards). Due to the Atlantic ocean’s meridional overturning circulation, however, the ocean carries significantly more heat northwards across the equator (order 0.4 PW) than does the coupled system. There are two primary consequences. First, atmospheric heat transport is southwards across the equator to compensate (0.2 PW southwards), resulting in the ITCZ being displaced north of the equator. Second, the atmosphere, and indeed the ocean, is slightly warmer (by perhaps 2 °C) in the northern hemisphere than in the southern hemisphere. This leads to the northern hemisphere emitting slightly more outgoing longwave radiation than the southern hemisphere by virtue of its relative warmth, supporting the small northward heat transport by the coupled system across the equator. To conclude, the coupled nature of the problem is illustrated through study of atmosphere–ocean–ice simulations in the idealized setting of an aquaplanet, resolving the key processes at work. United States. National Oceanic and Atmospheric Administration (Postdoctoral Fellowship) United States. National Oceanic and Atmospheric Administration National Science Foundation (U.S.) 2014-03-10T19:23:47Z 2014-03-10T19:23:47Z 2013-05 2012-12 Article http://purl.org/eprint/type/JournalArticle 0930-7575 1432-0894 http://hdl.handle.net/1721.1/85592 Marshall, J., A. Donohoe, D. Ferreira, and D. McGee. “The Ocean’s Role in Setting the Mean Position of the Inter-Tropical Convergence Zone.” Climate Dynamics (May 1, 2013). https://orcid.org/0000-0001-9230-3591 en_US http://dx.doi.org/10.1007/s00382-013-1767-z Climate Dynamics Article is available under a Creative Commons license; see publisher's site for details. http://creativecommons.org/ application/pdf Springer-Verlag Springer |
| spellingShingle | Donohoe, Aaron Ferreira, David Marshall, John C McGee, William David The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title | The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title_full | The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title_fullStr | The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title_full_unstemmed | The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title_short | The ocean’s role in setting the mean position of the Inter-Tropical Convergence Zone |
| title_sort | ocean s role in setting the mean position of the inter tropical convergence zone |
| url | http://hdl.handle.net/1721.1/85592 https://orcid.org/0000-0001-9230-3591 |
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