Estimating oceanic heat content change using isotherms
This paper presents a new analysis of ocean heat content changes over the last 50 yr using isotherms by calculating the mean temperature above the 14°C isotherm and the depth of the 14°C isotherm as separate variables. A new quantity called the "relative heat content" ("RHC") is...
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Online Access: | https://hdl.handle.net/1983/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://research-information.bris.ac.uk/en/publications/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://doi.org/10.1175/2009JCLI2823.1 http://www.scopus.com/inward/record.url?scp=72149115882&partnerID=8YFLogxK |
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ftubristolcris:oai:research-information.bris.ac.uk:publications/aaa517a8-36f0-4cf3-9f26-1b10105ed84d 2024-02-04T10:02:29+01:00 Estimating oceanic heat content change using isotherms Palmer, Matthew D. Haines, Keith 2009-10 https://hdl.handle.net/1983/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://research-information.bris.ac.uk/en/publications/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://doi.org/10.1175/2009JCLI2823.1 http://www.scopus.com/inward/record.url?scp=72149115882&partnerID=8YFLogxK eng eng info:eu-repo/semantics/openAccess Palmer , M D & Haines , K 2009 , ' Estimating oceanic heat content change using isotherms ' , Journal of Climate , vol. 22 , no. 19 , pp. 4953-4969 . https://doi.org/10.1175/2009JCLI2823.1 article 2009 ftubristolcris https://doi.org/10.1175/2009JCLI2823.1 2024-01-11T23:49:12Z This paper presents a new analysis of ocean heat content changes over the last 50 yr using isotherms by calculating the mean temperature above the 14°C isotherm and the depth of the 14°C isotherm as separate variables. A new quantity called the "relative heat content" ("RHC") is introduced, which represents the minimum local heat content change over time, relative to a fixed isotherm. It is shown how mean temperature and isotherm depth changes make separable and additive contributions to changes in RHC. Maps of RHC change between 1970 and 2000 show similar spatial patterns to a traditional fixed-depth ocean heat content change to 220 m. However, the separate contributions to RHC suggest a more spatially uniform contribution from warming above the isotherm, while isotherm depth changes show wind-driven signals, of which some are identifiable as being related to the North Atlantic Oscillation. The time series show that the warming contribution to RHC dominates the global trend, while the depth contribution only dominates on the basin scale in the North Atlantic. The RHC shows minima associated with the major volcanic eruptions (particularly in the Indian Ocean), and these are entirely contributed by mean temperature changes rather than isotherm depth changes. The depth change contributions to RHC are strongly affected by the recently reported XBT fall-rate bias, whereas the mean temperature contributions are not. Therefore, only the isotherm depth change contributions toRHCwill need to be reassessed as fall-rate-corrected data become available. Article in Journal/Newspaper North Atlantic North Atlantic oscillation University of Bristol: Bristol Research Indian Journal of Climate 22 19 4953 4969 |
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Open Polar |
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University of Bristol: Bristol Research |
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ftubristolcris |
language |
English |
description |
This paper presents a new analysis of ocean heat content changes over the last 50 yr using isotherms by calculating the mean temperature above the 14°C isotherm and the depth of the 14°C isotherm as separate variables. A new quantity called the "relative heat content" ("RHC") is introduced, which represents the minimum local heat content change over time, relative to a fixed isotherm. It is shown how mean temperature and isotherm depth changes make separable and additive contributions to changes in RHC. Maps of RHC change between 1970 and 2000 show similar spatial patterns to a traditional fixed-depth ocean heat content change to 220 m. However, the separate contributions to RHC suggest a more spatially uniform contribution from warming above the isotherm, while isotherm depth changes show wind-driven signals, of which some are identifiable as being related to the North Atlantic Oscillation. The time series show that the warming contribution to RHC dominates the global trend, while the depth contribution only dominates on the basin scale in the North Atlantic. The RHC shows minima associated with the major volcanic eruptions (particularly in the Indian Ocean), and these are entirely contributed by mean temperature changes rather than isotherm depth changes. The depth change contributions to RHC are strongly affected by the recently reported XBT fall-rate bias, whereas the mean temperature contributions are not. Therefore, only the isotherm depth change contributions toRHCwill need to be reassessed as fall-rate-corrected data become available. |
format |
Article in Journal/Newspaper |
author |
Palmer, Matthew D. Haines, Keith |
spellingShingle |
Palmer, Matthew D. Haines, Keith Estimating oceanic heat content change using isotherms |
author_facet |
Palmer, Matthew D. Haines, Keith |
author_sort |
Palmer, Matthew D. |
title |
Estimating oceanic heat content change using isotherms |
title_short |
Estimating oceanic heat content change using isotherms |
title_full |
Estimating oceanic heat content change using isotherms |
title_fullStr |
Estimating oceanic heat content change using isotherms |
title_full_unstemmed |
Estimating oceanic heat content change using isotherms |
title_sort |
estimating oceanic heat content change using isotherms |
publishDate |
2009 |
url |
https://hdl.handle.net/1983/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://research-information.bris.ac.uk/en/publications/aaa517a8-36f0-4cf3-9f26-1b10105ed84d https://doi.org/10.1175/2009JCLI2823.1 http://www.scopus.com/inward/record.url?scp=72149115882&partnerID=8YFLogxK |
geographic |
Indian |
geographic_facet |
Indian |
genre |
North Atlantic North Atlantic oscillation |
genre_facet |
North Atlantic North Atlantic oscillation |
op_source |
Palmer , M D & Haines , K 2009 , ' Estimating oceanic heat content change using isotherms ' , Journal of Climate , vol. 22 , no. 19 , pp. 4953-4969 . https://doi.org/10.1175/2009JCLI2823.1 |
op_rights |
info:eu-repo/semantics/openAccess |
op_doi |
https://doi.org/10.1175/2009JCLI2823.1 |
container_title |
Journal of Climate |
container_volume |
22 |
container_issue |
19 |
container_start_page |
4953 |
op_container_end_page |
4969 |
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1789969177157566464 |