The Neutral Density Temporal Residual Mean overturning circulation
Diagnosis of the ocean's overturning circulation is essential to closing global budgets of heat, salt and biogeochemical tracers. This diagnosis is sensitive to the choice of density variable used to distinguish water masses and identify transformations between them. The oceanographic community...
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Online Access: | https://doi.org/10.1016/j.ocemod.2015.03.005 |
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ftcaltechauth:oai:authors.library.caltech.edu:br26q-jrg74 2024-10-13T14:02:37+00:00 The Neutral Density Temporal Residual Mean overturning circulation Stewart, A. L. Thompson, A. F. 2015-06 https://doi.org/10.1016/j.ocemod.2015.03.005 unknown Elsevier https://doi.org/10.1016/j.ocemod.2015.03.005 eprintid:58344 info:eu-repo/semantics/closedAccess Other Ocean Modelling, 90, 44-56, (2015-06) Transformed residual mean Neutral density Ocean overturning Antarctic circulation info:eu-repo/semantics/article 2015 ftcaltechauth https://doi.org/10.1016/j.ocemod.2015.03.005 2024-09-25T18:46:42Z Diagnosis of the ocean's overturning circulation is essential to closing global budgets of heat, salt and biogeochemical tracers. This diagnosis is sensitive to the choice of density variable used to distinguish water masses and identify transformations between them. The oceanographic community has adopted neutral density for this purpose because its isopycnal slopes are approximately aligned with neutral slopes, along which ocean flows tend to be confined. At high latitudes there are often no tenable alternatives because potential density varies non-monotonically with depth, regardless of the reference pressure. However, in many applications the use of isoneutral fluxes is impractical due to the high computational cost of calculating neutral density. Consequently neutral density-related diagnostics are typically not available as output from ocean models. In this article the authors derive a modified Temporal Residual Mean (TRM) approximation to the isoneutral mass fluxes, referred to as the Neutral Density Temporal Residual Mean (NDTRM). The NDTRM may be calculated using quantities that are routinely offered as diagnostic output from ocean models, making it several orders of magnitude faster than explicitly computing isoneutral mass fluxes. The NDTRM is assessed using a process model of the Antarctic continental shelf and slope. The onshore transport of warm Circumpolar Deep Water in the model ocean interior approximately doubles when diagnosed using neutral density, rather than potential density. The NDTRM closely approximates these explicitly-computed isoneutral mass fluxes. The NDTRM also exhibits a much smaller error than the traditional TRM in regions of large isoneutral temperature and salinity gradients, where nonlinearities in the equation of state diabatically modify the neutral density. © 2015 Elsevier Ltd. Received 19 September 2014; Revised 23 March 2015; Accepted 25 March 2015; Available online 02 April 2015. A.L.S.'s and A.F.T.'s work was carried out at the California Institute of Technology ... Article in Journal/Newspaper Antarc* Antarctic Caltech Authors (California Institute of Technology) Antarctic The Antarctic Ocean Modelling 90 44 56 |
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Caltech Authors (California Institute of Technology) |
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topic |
Transformed residual mean Neutral density Ocean overturning Antarctic circulation |
spellingShingle |
Transformed residual mean Neutral density Ocean overturning Antarctic circulation Stewart, A. L. Thompson, A. F. The Neutral Density Temporal Residual Mean overturning circulation |
topic_facet |
Transformed residual mean Neutral density Ocean overturning Antarctic circulation |
description |
Diagnosis of the ocean's overturning circulation is essential to closing global budgets of heat, salt and biogeochemical tracers. This diagnosis is sensitive to the choice of density variable used to distinguish water masses and identify transformations between them. The oceanographic community has adopted neutral density for this purpose because its isopycnal slopes are approximately aligned with neutral slopes, along which ocean flows tend to be confined. At high latitudes there are often no tenable alternatives because potential density varies non-monotonically with depth, regardless of the reference pressure. However, in many applications the use of isoneutral fluxes is impractical due to the high computational cost of calculating neutral density. Consequently neutral density-related diagnostics are typically not available as output from ocean models. In this article the authors derive a modified Temporal Residual Mean (TRM) approximation to the isoneutral mass fluxes, referred to as the Neutral Density Temporal Residual Mean (NDTRM). The NDTRM may be calculated using quantities that are routinely offered as diagnostic output from ocean models, making it several orders of magnitude faster than explicitly computing isoneutral mass fluxes. The NDTRM is assessed using a process model of the Antarctic continental shelf and slope. The onshore transport of warm Circumpolar Deep Water in the model ocean interior approximately doubles when diagnosed using neutral density, rather than potential density. The NDTRM closely approximates these explicitly-computed isoneutral mass fluxes. The NDTRM also exhibits a much smaller error than the traditional TRM in regions of large isoneutral temperature and salinity gradients, where nonlinearities in the equation of state diabatically modify the neutral density. © 2015 Elsevier Ltd. Received 19 September 2014; Revised 23 March 2015; Accepted 25 March 2015; Available online 02 April 2015. A.L.S.'s and A.F.T.'s work was carried out at the California Institute of Technology ... |
format |
Article in Journal/Newspaper |
author |
Stewart, A. L. Thompson, A. F. |
author_facet |
Stewart, A. L. Thompson, A. F. |
author_sort |
Stewart, A. L. |
title |
The Neutral Density Temporal Residual Mean overturning circulation |
title_short |
The Neutral Density Temporal Residual Mean overturning circulation |
title_full |
The Neutral Density Temporal Residual Mean overturning circulation |
title_fullStr |
The Neutral Density Temporal Residual Mean overturning circulation |
title_full_unstemmed |
The Neutral Density Temporal Residual Mean overturning circulation |
title_sort |
neutral density temporal residual mean overturning circulation |
publisher |
Elsevier |
publishDate |
2015 |
url |
https://doi.org/10.1016/j.ocemod.2015.03.005 |
geographic |
Antarctic The Antarctic |
geographic_facet |
Antarctic The Antarctic |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_source |
Ocean Modelling, 90, 44-56, (2015-06) |
op_relation |
https://doi.org/10.1016/j.ocemod.2015.03.005 eprintid:58344 |
op_rights |
info:eu-repo/semantics/closedAccess Other |
op_doi |
https://doi.org/10.1016/j.ocemod.2015.03.005 |
container_title |
Ocean Modelling |
container_volume |
90 |
container_start_page |
44 |
op_container_end_page |
56 |
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1812818733117210624 |