Recent water mass changes reveal mechanisms of ocean warming
Over 90% of the buildup of additional heat in the Earth system over recent decades is contained in the ocean. Since 2006, new observational programs have revealed heterogeneous patterns of ocean heat content change. It is unclear how much of this heterogeneity is due to heat being added to and mixed...
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ftunswworks:oai:unsworks.library.unsw.edu.au:1959.4/unsworks_75574 2024-05-12T08:08:13+00:00 Recent water mass changes reveal mechanisms of ocean warming Zika, JD Gregory, JM McDonagh, EL Marzocchi, A Clément, L 2021-03-01 http://hdl.handle.net/1959.4/unsworks_75574 https://doi.org/10.1175/jcli-d-20-0355.1 unknown American Meteorological Society http://purl.org/au-research/grants/arc/DP190101173 http://hdl.handle.net/1959.4/unsworks_75574 https://doi.org/10.1175/jcli-d-20-0355.1 metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ urn:ISSN:0894-8755 urn:ISSN:1520-0442 Journal of Climate, 34, 9, 3461-3479 13 Climate Action anzsrc-for: 0401 Atmospheric Sciences anzsrc-for: 0405 Oceanography anzsrc-for: 0909 Geomatic Engineering journal article http://purl.org/coar/resource_type/c_6501 2021 ftunswworks https://doi.org/10.1175/jcli-d-20-0355.1 2024-04-17T15:02:21Z Over 90% of the buildup of additional heat in the Earth system over recent decades is contained in the ocean. Since 2006, new observational programs have revealed heterogeneous patterns of ocean heat content change. It is unclear how much of this heterogeneity is due to heat being added to and mixed within the ocean leading to material changes in water mass properties or is due to changes in circulation that redistribute existing water masses. Here we present a novel diagnosis of the ''material'' and ''redistributed'' contributions to regional heat content change between 2006 and 2017 that is based on a new ''minimum transformation method'' informed by both water mass transformation and optimal transportation theory. We show that material warming has large spatial coherence. The material change tends to be smaller than the redistributed change at any geographical location; however, it sums globally to the net warming of the ocean, whereas the redistributed component sums, by design, to zero. Material warming is robust over the time period of this analysis, whereas the redistributed signal only emerges from the variability in a few regions. In the North Atlantic Ocean, water mass changes indicate substantial material warming while redistribution cools the subpolar region as a result of a slowdown in the meridional overturning circulation. Warming in the Southern Ocean is explained by material warming and by anomalous southward heat transport of 118 6 50 TW through redistribution. Our results suggest that near-term projections of ocean heat content change and therefore sea level change will hinge on understanding and predicting changes in ocean redistribution. Article in Journal/Newspaper North Atlantic Southern Ocean UNSW Sydney (The University of New South Wales): UNSWorks Southern Ocean Journal of Climate 34 9 3461 3479 |
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UNSW Sydney (The University of New South Wales): UNSWorks |
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language |
unknown |
topic |
13 Climate Action anzsrc-for: 0401 Atmospheric Sciences anzsrc-for: 0405 Oceanography anzsrc-for: 0909 Geomatic Engineering |
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13 Climate Action anzsrc-for: 0401 Atmospheric Sciences anzsrc-for: 0405 Oceanography anzsrc-for: 0909 Geomatic Engineering Zika, JD Gregory, JM McDonagh, EL Marzocchi, A Clément, L Recent water mass changes reveal mechanisms of ocean warming |
topic_facet |
13 Climate Action anzsrc-for: 0401 Atmospheric Sciences anzsrc-for: 0405 Oceanography anzsrc-for: 0909 Geomatic Engineering |
description |
Over 90% of the buildup of additional heat in the Earth system over recent decades is contained in the ocean. Since 2006, new observational programs have revealed heterogeneous patterns of ocean heat content change. It is unclear how much of this heterogeneity is due to heat being added to and mixed within the ocean leading to material changes in water mass properties or is due to changes in circulation that redistribute existing water masses. Here we present a novel diagnosis of the ''material'' and ''redistributed'' contributions to regional heat content change between 2006 and 2017 that is based on a new ''minimum transformation method'' informed by both water mass transformation and optimal transportation theory. We show that material warming has large spatial coherence. The material change tends to be smaller than the redistributed change at any geographical location; however, it sums globally to the net warming of the ocean, whereas the redistributed component sums, by design, to zero. Material warming is robust over the time period of this analysis, whereas the redistributed signal only emerges from the variability in a few regions. In the North Atlantic Ocean, water mass changes indicate substantial material warming while redistribution cools the subpolar region as a result of a slowdown in the meridional overturning circulation. Warming in the Southern Ocean is explained by material warming and by anomalous southward heat transport of 118 6 50 TW through redistribution. Our results suggest that near-term projections of ocean heat content change and therefore sea level change will hinge on understanding and predicting changes in ocean redistribution. |
format |
Article in Journal/Newspaper |
author |
Zika, JD Gregory, JM McDonagh, EL Marzocchi, A Clément, L |
author_facet |
Zika, JD Gregory, JM McDonagh, EL Marzocchi, A Clément, L |
author_sort |
Zika, JD |
title |
Recent water mass changes reveal mechanisms of ocean warming |
title_short |
Recent water mass changes reveal mechanisms of ocean warming |
title_full |
Recent water mass changes reveal mechanisms of ocean warming |
title_fullStr |
Recent water mass changes reveal mechanisms of ocean warming |
title_full_unstemmed |
Recent water mass changes reveal mechanisms of ocean warming |
title_sort |
recent water mass changes reveal mechanisms of ocean warming |
publisher |
American Meteorological Society |
publishDate |
2021 |
url |
http://hdl.handle.net/1959.4/unsworks_75574 https://doi.org/10.1175/jcli-d-20-0355.1 |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
North Atlantic Southern Ocean |
genre_facet |
North Atlantic Southern Ocean |
op_source |
urn:ISSN:0894-8755 urn:ISSN:1520-0442 Journal of Climate, 34, 9, 3461-3479 |
op_relation |
http://purl.org/au-research/grants/arc/DP190101173 http://hdl.handle.net/1959.4/unsworks_75574 https://doi.org/10.1175/jcli-d-20-0355.1 |
op_rights |
metadata only access http://purl.org/coar/access_right/c_14cb CC-BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/ |
op_doi |
https://doi.org/10.1175/jcli-d-20-0355.1 |
container_title |
Journal of Climate |
container_volume |
34 |
container_issue |
9 |
container_start_page |
3461 |
op_container_end_page |
3479 |
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1798851151692562432 |