Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies
In this paper, two new quasi-neutral density variables — generalised patched potential density (GPPD) and thermodynamic neutral density γT — are introduced, which are showed to approximate Jackett and McDougall (1997) empirical neutral density γn significantly better than the quasi-material rational...
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American Meteorological Society
2016
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ftunivreading:oai:centaur.reading.ac.uk:66906 2024-06-23T07:56:56+00:00 Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies Tailleux, Remi 2016-12 text https://centaur.reading.ac.uk/66906/ https://centaur.reading.ac.uk/66906/7/jpo-d-16-0072%252E1.pdf https://centaur.reading.ac.uk/66906/1/new_paradigm_R2.pdf en eng American Meteorological Society https://centaur.reading.ac.uk/66906/7/jpo-d-16-0072%252E1.pdf https://centaur.reading.ac.uk/66906/1/new_paradigm_R2.pdf Tailleux, R. <https://centaur.reading.ac.uk/view/creators/90000948.html> orcid:0000-0001-8998-9107 (2016) Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies. Journal of Physical Oceanography, 46 (12). pp. 3571-3584. ISSN 0022-3670 doi: https://doi.org/10.1175/JPO-D-16-0072.1 <https://doi.org/10.1175/JPO-D-16-0072.1> cc_by_4 Article PeerReviewed 2016 ftunivreading https://doi.org/10.1175/JPO-D-16-0072.1 2024-06-11T15:05:53Z In this paper, two new quasi-neutral density variables — generalised patched potential density (GPPD) and thermodynamic neutral density γT — are introduced, which are showed to approximate Jackett and McDougall (1997) empirical neutral density γn significantly better than the quasi-material rational polynomial approximation γa previously introduced by McDougall and Jackett (2005b). In contrast to γn, γT is easily and efficiently computed for arbitrary climatologies of temperature and salinity, both realistic and idealised, has a clear physical basis rooted in the theory of available potential energy, and does not suffer from non-material effects that makes γn so difficult to use in water masses analysis. In addition, γT is also significantly more neutral than all known quasi-material density variables, such as σ2, while remaining less neutral than γn. Because unlike γn, γT is mathematically explicit, it can be used for theoretical as well as observational studies, as well as a generalised vertical coordinate in isopycnal models of the ocean circulation. On the downside, γT exhibits inversions and degraded neutrality in the polar regions, where Lorenz reference state is the furthest away from the actual state. Therefore, while γT represents progress over previous approaches, further work is still needed to determine whether its polar deficiencies can be corrected, an essential requirement for γT to be useful in Southern Ocean studies for instance. Article in Journal/Newspaper Southern Ocean CentAUR: Central Archive at the University of Reading Southern Ocean Journal of Physical Oceanography 46 12 3571 3584 |
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CentAUR: Central Archive at the University of Reading |
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ftunivreading |
language |
English |
description |
In this paper, two new quasi-neutral density variables — generalised patched potential density (GPPD) and thermodynamic neutral density γT — are introduced, which are showed to approximate Jackett and McDougall (1997) empirical neutral density γn significantly better than the quasi-material rational polynomial approximation γa previously introduced by McDougall and Jackett (2005b). In contrast to γn, γT is easily and efficiently computed for arbitrary climatologies of temperature and salinity, both realistic and idealised, has a clear physical basis rooted in the theory of available potential energy, and does not suffer from non-material effects that makes γn so difficult to use in water masses analysis. In addition, γT is also significantly more neutral than all known quasi-material density variables, such as σ2, while remaining less neutral than γn. Because unlike γn, γT is mathematically explicit, it can be used for theoretical as well as observational studies, as well as a generalised vertical coordinate in isopycnal models of the ocean circulation. On the downside, γT exhibits inversions and degraded neutrality in the polar regions, where Lorenz reference state is the furthest away from the actual state. Therefore, while γT represents progress over previous approaches, further work is still needed to determine whether its polar deficiencies can be corrected, an essential requirement for γT to be useful in Southern Ocean studies for instance. |
format |
Article in Journal/Newspaper |
author |
Tailleux, Remi |
spellingShingle |
Tailleux, Remi Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
author_facet |
Tailleux, Remi |
author_sort |
Tailleux, Remi |
title |
Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
title_short |
Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
title_full |
Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
title_fullStr |
Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
title_full_unstemmed |
Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
title_sort |
generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies |
publisher |
American Meteorological Society |
publishDate |
2016 |
url |
https://centaur.reading.ac.uk/66906/ https://centaur.reading.ac.uk/66906/7/jpo-d-16-0072%252E1.pdf https://centaur.reading.ac.uk/66906/1/new_paradigm_R2.pdf |
geographic |
Southern Ocean |
geographic_facet |
Southern Ocean |
genre |
Southern Ocean |
genre_facet |
Southern Ocean |
op_relation |
https://centaur.reading.ac.uk/66906/7/jpo-d-16-0072%252E1.pdf https://centaur.reading.ac.uk/66906/1/new_paradigm_R2.pdf Tailleux, R. <https://centaur.reading.ac.uk/view/creators/90000948.html> orcid:0000-0001-8998-9107 (2016) Generalised patched potential density and thermodynamic neutral density: two new physically-based quasi-neutral density variables for ocean water masses analyses and circulation studies. Journal of Physical Oceanography, 46 (12). pp. 3571-3584. ISSN 0022-3670 doi: https://doi.org/10.1175/JPO-D-16-0072.1 <https://doi.org/10.1175/JPO-D-16-0072.1> |
op_rights |
cc_by_4 |
op_doi |
https://doi.org/10.1175/JPO-D-16-0072.1 |
container_title |
Journal of Physical Oceanography |
container_volume |
46 |
container_issue |
12 |
container_start_page |
3571 |
op_container_end_page |
3584 |
_version_ |
1802650331973156864 |