The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater

As seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. These cha...

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Main Authors: R. Pawlowicz, D. G. Wright, F. J. Millero
Format: Article
Language:English
Published: Copernicus Publications 2011-06-01
Series:Ocean Science
Online Access:http://www.ocean-sci.net/7/363/2011/os-7-363-2011.pdf
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spelling doaj-b1f9c7f9a5c5407c928de466648c7ed32020-11-25T01:01:33ZengCopernicus PublicationsOcean Science1812-07841812-07922011-06-017336338710.5194/os-7-363-2011The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawaterR. PawlowiczD. G. WrightF. J. MilleroAs seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. These changes are investigated here by analysis of laboratory experiments in which salts are added to seawater, by analysis of oceanic observations of density and composition anomalies, and by mathematical investigation using a model relating composition, conductivity, and density of arbitrary seawaters. Mathematical analysis shows that understanding and describing the effect of changes in relative composition on operational estimates of salinity using the Practical Salinity Scale 1978 and on density using an equation of state for Standard Seawater require the use of a number of different salinity variables and a family of haline contraction coefficients. These salinity variables include an absolute Salinity <i>S</i><sub>A</sub><sup>soln</sup>, a density salinity <i>S</i><sub>A</sub><sup>dens</sup>, the reference salinity <i>S</i><sub>R</sub>, and an added-mass salinity <i>S</i><sub>A</sub><sup>add</sup>. In addition, a new salinity variable <i>S</i><sub>∗</sub> is defined, which represents the preformed salinity of a Standard Seawater component of real seawater to which biogeochemical processes add material. In spite of this complexity, observed correlations between different ocean biogeochemical processes allow the creation of simple formulas that can be used to convert between the different salinity and density measures, allowing for the operational reduction of routine oceanographic observations.http://www.ocean-sci.net/7/363/2011/os-7-363-2011.pdf
collection DOAJ
language English
format Article
sources DOAJ
author R. Pawlowicz
D. G. Wright
F. J. Millero
spellingShingle R. Pawlowicz
D. G. Wright
F. J. Millero
The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
Ocean Science
author_facet R. Pawlowicz
D. G. Wright
F. J. Millero
author_sort R. Pawlowicz
title The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
title_short The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
title_full The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
title_fullStr The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
title_full_unstemmed The effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
title_sort effects of biogeochemical processes on oceanic conductivity/salinity/density relationships and the characterization of real seawater
publisher Copernicus Publications
series Ocean Science
issn 1812-0784
1812-0792
publishDate 2011-06-01
description As seawater circulates through the global ocean, its relative composition undergoes small variations. This results in changes to the conductivity/salinity/density relationship, which is currently well-defined only for Standard Seawater obtained from a particular area in the North Atlantic. These changes are investigated here by analysis of laboratory experiments in which salts are added to seawater, by analysis of oceanic observations of density and composition anomalies, and by mathematical investigation using a model relating composition, conductivity, and density of arbitrary seawaters. Mathematical analysis shows that understanding and describing the effect of changes in relative composition on operational estimates of salinity using the Practical Salinity Scale 1978 and on density using an equation of state for Standard Seawater require the use of a number of different salinity variables and a family of haline contraction coefficients. These salinity variables include an absolute Salinity <i>S</i><sub>A</sub><sup>soln</sup>, a density salinity <i>S</i><sub>A</sub><sup>dens</sup>, the reference salinity <i>S</i><sub>R</sub>, and an added-mass salinity <i>S</i><sub>A</sub><sup>add</sup>. In addition, a new salinity variable <i>S</i><sub>∗</sub> is defined, which represents the preformed salinity of a Standard Seawater component of real seawater to which biogeochemical processes add material. In spite of this complexity, observed correlations between different ocean biogeochemical processes allow the creation of simple formulas that can be used to convert between the different salinity and density measures, allowing for the operational reduction of routine oceanographic observations.
url http://www.ocean-sci.net/7/363/2011/os-7-363-2011.pdf
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