Meridional Heat and Salt Transport Across the Subantarctic Front by Cold‐Core Eddies.
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| Title: | Meridional Heat and Salt Transport Across the Subantarctic Front by Cold‐Core Eddies. |
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| Authors: | Patel, Ramkrushnbhai S.1,2 Ramkrushnbhai.Patel@utas.edu.au, Phillips, Helen E.1,3, Strutton, Peter G.1,3, Lenton, Andrew4,5,6, Llort, Joan1,2 |
| Source: | Journal of Geophysical Research. Oceans. Feb2019, Vol. 124 Issue 2, p981-1004. 24p. |
| Subject Terms: | Mesoscale eddies, Heat transfer, Salt content of seawater, Antarctic Circumpolar Current, Heat flux |
| Abstract: | Mesoscale eddies are ubiquitous in the Southern Ocean particularly in regions where the Antarctic Circumpolar Current interacts with topography. Eddies play a critical role in the meridional transport of heat and salt across the Antarctic Circumpolar Current. However, observations of the heat and salt content of eddies are extremely rare. Here we present new observations that characterize the three‐dimensional structure of a cyclonic (cold‐core) eddy generated at the Subantarctic Front south of Tasmania. Automated detection software is used with satellite altimetry to follow the eddy through the Subantarctic Zone. The physical properties at the center of the eddy are substantially modified from those near the formation region, indicating a strong transformation during the eddy's lifetime. The eddy carried heat and salt content anomalies relative to surrounding Subantarctic Zone waters of −0.5 ± 0.1 × 1020 J and −2.1 ± 0.4 × 1012 kg, respectively. Previous studies have not captured the full heat and salt content of eddies due to limited observations and have underestimated their content by a factor of 2 to 3 south of Tasmania. Applying the observed correlation between eddy‐elevated volume and eddy heat and salt content to the history of cyclonic eddies in the satellite altimeter record leads us to propose that about 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by cyclonic eddies entering the Subantarctic Zone. The freshwater contribution to the Subantarctic Zone by long‐lived cold‐core eddies is of the same order of magnitude as the Ekman flux in this region. Plain Language Summary: Eddies are rotating bodies of water with diameters between 10 and 100 km that live from a week to months in the ocean. They are known to carry heat and salt across the Antarctic Circumpolar Current. Because of extremely limited direct observations of these eddies, it is difficult to calculate the actual amount of heat and salt that these eddies carry. Here we present new observations of a cold‐core eddy that we sampled during a voyage in the Southern Ocean south of Tasmania. The eddy was born in the Subantarctic Front and traveled into the Subantarctic Zone where it stayed for 2 months before returning to the Subantarctic Front and disappearing. The observations showed that the amount of heat carried into the Subantarctic Zone is 2.6 times higher than previously reported, and the amount of salt is 2.5 times larger for south of Tasmania. Based on our in situ observations, combined with satellite measurements of sea surface height and an eddy‐tracking software, we propose that 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by long‐lived, cold‐core eddies entering the Subantarctic Zone. Key Points: We characterize for the first time the physical structure of a Subantarctic Front cold‐core eddy, south of Tasmania in the Southern OceanLong‐lived cold‐core eddies transport about 21% of the required meridional heat flux across the Subantarctic FrontPrevious studies have underestimated the total heat and salt content transport by cold‐core eddies due to limited observations [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Geophysical Research. Oceans is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
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| Header | DbId: 8gh DbLabel: GreenFILE An: 135402063 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Meridional Heat and Salt Transport Across the Subantarctic Front by Cold‐Core Eddies. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Patel%2C+Ramkrushnbhai+S%2E%22">Patel, Ramkrushnbhai S.</searchLink><relatesTo>1,2</relatesTo><i> Ramkrushnbhai.Patel@utas.edu.au</i><br /><searchLink fieldCode="AR" term="%22Phillips%2C+Helen+E%2E%22">Phillips, Helen E.</searchLink><relatesTo>1,3</relatesTo><br /><searchLink fieldCode="AR" term="%22Strutton%2C+Peter+G%2E%22">Strutton, Peter G.</searchLink><relatesTo>1,3</relatesTo><br /><searchLink fieldCode="AR" term="%22Lenton%2C+Andrew%22">Lenton, Andrew</searchLink><relatesTo>4,5,6</relatesTo><br /><searchLink fieldCode="AR" term="%22Llort%2C+Joan%22">Llort, Joan</searchLink><relatesTo>1,2</relatesTo> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Geophysical+Research%2E+Oceans%22">Journal of Geophysical Research. Oceans</searchLink>. Feb2019, Vol. 124 Issue 2, p981-1004. 24p. – Name: Subject Label: Subject Terms Group: Su Data: <searchLink fieldCode="DE" term="%22Mesoscale+eddies%22">Mesoscale eddies</searchLink><br /><searchLink fieldCode="DE" term="%22Heat+transfer%22">Heat transfer</searchLink><br /><searchLink fieldCode="DE" term="%22Salt+content+of+seawater%22">Salt content of seawater</searchLink><br /><searchLink fieldCode="DE" term="%22Antarctic+Circumpolar+Current%22">Antarctic Circumpolar Current</searchLink><br /><searchLink fieldCode="DE" term="%22Heat+flux%22">Heat flux</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: Mesoscale eddies are ubiquitous in the Southern Ocean particularly in regions where the Antarctic Circumpolar Current interacts with topography. Eddies play a critical role in the meridional transport of heat and salt across the Antarctic Circumpolar Current. However, observations of the heat and salt content of eddies are extremely rare. Here we present new observations that characterize the three‐dimensional structure of a cyclonic (cold‐core) eddy generated at the Subantarctic Front south of Tasmania. Automated detection software is used with satellite altimetry to follow the eddy through the Subantarctic Zone. The physical properties at the center of the eddy are substantially modified from those near the formation region, indicating a strong transformation during the eddy's lifetime. The eddy carried heat and salt content anomalies relative to surrounding Subantarctic Zone waters of −0.5 ± 0.1 × 1020 J and −2.1 ± 0.4 × 1012 kg, respectively. Previous studies have not captured the full heat and salt content of eddies due to limited observations and have underestimated their content by a factor of 2 to 3 south of Tasmania. Applying the observed correlation between eddy‐elevated volume and eddy heat and salt content to the history of cyclonic eddies in the satellite altimeter record leads us to propose that about 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by cyclonic eddies entering the Subantarctic Zone. The freshwater contribution to the Subantarctic Zone by long‐lived cold‐core eddies is of the same order of magnitude as the Ekman flux in this region. Plain Language Summary: Eddies are rotating bodies of water with diameters between 10 and 100 km that live from a week to months in the ocean. They are known to carry heat and salt across the Antarctic Circumpolar Current. Because of extremely limited direct observations of these eddies, it is difficult to calculate the actual amount of heat and salt that these eddies carry. Here we present new observations of a cold‐core eddy that we sampled during a voyage in the Southern Ocean south of Tasmania. The eddy was born in the Subantarctic Front and traveled into the Subantarctic Zone where it stayed for 2 months before returning to the Subantarctic Front and disappearing. The observations showed that the amount of heat carried into the Subantarctic Zone is 2.6 times higher than previously reported, and the amount of salt is 2.5 times larger for south of Tasmania. Based on our in situ observations, combined with satellite measurements of sea surface height and an eddy‐tracking software, we propose that 21% of the heat carried across the Subantarctic Front south of Tasmania is achieved by long‐lived, cold‐core eddies entering the Subantarctic Zone. Key Points: We characterize for the first time the physical structure of a Subantarctic Front cold‐core eddy, south of Tasmania in the Southern OceanLong‐lived cold‐core eddies transport about 21% of the required meridional heat flux across the Subantarctic FrontPrevious studies have underestimated the total heat and salt content transport by cold‐core eddies due to limited observations [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Geophysical Research. Oceans is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1029/2018JC014655 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 24 StartPage: 981 Subjects: – SubjectFull: Mesoscale eddies Type: general – SubjectFull: Heat transfer Type: general – SubjectFull: Salt content of seawater Type: general – SubjectFull: Antarctic Circumpolar Current Type: general – SubjectFull: Heat flux Type: general Titles: – TitleFull: Meridional Heat and Salt Transport Across the Subantarctic Front by Cold‐Core Eddies. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Patel, Ramkrushnbhai S. – PersonEntity: Name: NameFull: Phillips, Helen E. – PersonEntity: Name: NameFull: Strutton, Peter G. – PersonEntity: Name: NameFull: Lenton, Andrew – PersonEntity: Name: NameFull: Llort, Joan IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2019 Type: published Y: 2019 Identifiers: – Type: issn-print Value: 21699275 Numbering: – Type: volume Value: 124 – Type: issue Value: 2 Titles: – TitleFull: Journal of Geophysical Research. Oceans Type: main |
| ResultId | 1 |
