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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2015
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Online Access: | https://escholarship.org/uc/item/4hw76818 https://escholarship.org/content/qt4hw76818/qt4hw76818.pdf https://doi.org/10.1016/j.ocemod.2015.03.005 |
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ftcdlib:oai:escholarship.org:ark:/13030/qt4hw76818 2024-09-15T17:40:22+00:00 The Neutral Density Temporal Residual Mean overturning circulation Stewart, AL Thompson, AF 2015-06-01 application/pdf https://escholarship.org/uc/item/4hw76818 https://escholarship.org/content/qt4hw76818/qt4hw76818.pdf https://doi.org/10.1016/j.ocemod.2015.03.005 unknown eScholarship, University of California qt4hw76818 https://escholarship.org/uc/item/4hw76818 https://escholarship.org/content/qt4hw76818/qt4hw76818.pdf doi:10.1016/j.ocemod.2015.03.005 public Life Below Water Transformed residual mean Neutral density Ocean overturning Antarctic circulation Oceanography Maritime Engineering article 2015 ftcdlib https://doi.org/10.1016/j.ocemod.2015.03.005 2024-06-28T06:28:19Z 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. Article in Journal/Newspaper Antarc* Antarctic University of California: eScholarship Ocean Modelling 90 44 56 |
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Open Polar |
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University of California: eScholarship |
op_collection_id |
ftcdlib |
language |
unknown |
topic |
Life Below Water Transformed residual mean Neutral density Ocean overturning Antarctic circulation Oceanography Maritime Engineering |
spellingShingle |
Life Below Water Transformed residual mean Neutral density Ocean overturning Antarctic circulation Oceanography Maritime Engineering Stewart, AL Thompson, AF The Neutral Density Temporal Residual Mean overturning circulation |
topic_facet |
Life Below Water Transformed residual mean Neutral density Ocean overturning Antarctic circulation Oceanography Maritime Engineering |
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. |
format |
Article in Journal/Newspaper |
author |
Stewart, AL Thompson, AF |
author_facet |
Stewart, AL Thompson, AF |
author_sort |
Stewart, AL |
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 |
eScholarship, University of California |
publishDate |
2015 |
url |
https://escholarship.org/uc/item/4hw76818 https://escholarship.org/content/qt4hw76818/qt4hw76818.pdf https://doi.org/10.1016/j.ocemod.2015.03.005 |
genre |
Antarc* Antarctic |
genre_facet |
Antarc* Antarctic |
op_relation |
qt4hw76818 https://escholarship.org/uc/item/4hw76818 https://escholarship.org/content/qt4hw76818/qt4hw76818.pdf doi:10.1016/j.ocemod.2015.03.005 |
op_rights |
public |
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 |
_version_ |
1810486397517168640 |