A global algorithm for estimating Absolute Salinity

McDougall, Trevor J.; Jackett, David R.; Millero, Frank J.; Pawlowicz, Rich; Barker, Paul M.

doi:10.5194/os-8-1123-2012

Cited by 128 publications

(94 citation statements)

References 18 publications

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“…But the practical way used to determine δS A is based on using density measurements [10]. As described by McDougall et al in 2012 [11] from a method suggested by Millero et al [3], δS A can be calculated with the equation:…”

Section: Introductionmentioning

confidence: 99%

Effect of Sediment Suspensions on Seawater Salinity Assessments

Menn¹

2017

WROS

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Abstract:The absolute salinity of seawater can be assessed by conductivity measurements and the calculation of a practical salinity, or by density measurements. The effect of low concentrations of suspended particulate matter on these measurements has never been documented, but the theories developed to explain and predict the conductivity of sediments show clearly that, under an electrical field, they interact with the ionic composition of seawater. Moreover, it can be easily shown that adding any quantity of particles has an effect on the measured density of a seawater sample. This publication describes a measurement method settled to measure the effect of sediment particles on seawater conductivity and proposes relations for explaining and predicting the observed phenomena. It also describes the effects of particles on density measurements. The results obtained show that the errors on the measured conductivities (and practical salinities) caused by sand in suspensions, are less than 0.001 mS cm -1 (on average) with concentrations encountered in oceans fields, but that these cannot be neglected in some coastal areas. The amplitude of the measurement noise leaded by particles circulation in the conductivity cell exceeds 0.002 in salinity beyond 200 mg l

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Section: Introductionmentioning

confidence: 99%

Effect of Sediment Suspensions on Seawater Salinity Assessments

Menn¹

2017

WROS

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“…However, salinities determined alternatively from both conductivity and chlorinity measurements somewhere in the world ocean may produce mutually inconsistent results. This happens especially if the chemical composition of seawater deviates from that of SSW, such as in the Baltic Sea (Wirth, 1940;Kwiecinski, 1965;Rohde, 1966;Millero and Kremling, 1976;Feistel et al, 2010c) or regionally in the global ocean Tsunogai et al, 1979;Millero, 2000a;Wright et al, 2011;Uchida et al, 2011;McDougall et al, 2012;Woosley et al, 2014). In cases when Eqs.…”

Section: Salinity Scalesmentioning

confidence: 99%

Thermodynamic properties of seawater, ice and humid air: TEOS-10, before and beyond

Feistel

2018

Ocean Sci.

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Abstract. In the terrestrial climate system, water is a key player in the form of its different ambient phases of ice, liquid and vapour, admixed with sea salt in the ocean and with dry air in the atmosphere. For proper balances of climatic energy and entropy fluxes in models and observations, a highly accurate, consistent and comprehensive thermodynamic standard framework is requisite in geophysics and climate research. The new Thermodynamic Equation of Seawater -2010 (TEOS-10) constitutes such a standard for properties of water in its various manifestations in the hydrological cycle.

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“…We came across one problem related to the TEOS-10 thermodynamic framework when applied to isolated eddies. Because the eddies transfer properties nearly unaltered over large distances the application of a regional (observing location) correction for the determination of the S A (McDougall et al, 2012) seems questionable. In the case of the surveyed eddy the impact was tested by applying the ion composition correction from 17 • W (eddy origin) and compared with the correction at the observational position, more than 700 km to the west, and a salinity difference of a little less than 0.001 g kg −1 was found.…”

Section: Glider Sensor Calibrationsmentioning

confidence: 99%

Upwelling and isolation in oxygen-depleted anticyclonic modewater eddies and implications for nitrate cycling

et al. 2017

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Abstract. The temporal evolution of the physical and biogeochemical structure of an oxygen-depleted anticyclonic modewater eddy is investigated over a 2-month period using high-resolution glider and ship data. A weakly stratified eddy core (squared buoyancy frequency N 2 ∼ 0.1 × 10 −4 s −2 ) at shallow depth is identified with a horizontal extent of about 70 km and bounded by maxima in N 2 . The upper N 2 maximum (3-5 × 10 −4 s −2 ) coincides with the mixed layer base and the lower N 2 maximum (0.4 × 10 −4 s −2 ) is found at about 200 m depth in the eddy centre. The eddy core shows a constant slope in temperature/salinity (T /S) characteristic over the 2 months, but an erosion of the core progressively narrows down the T /S range. The eddy minimal oxygen concentrations decreased by about 5 µmol kg −1 in 2 months, confirming earlier estimates of oxygen consumption rates in these eddies.Separating the mesoscale and perturbation flow components reveals oscillating velocity finestructure (∼ 0.1 m s −1 ) underneath the eddy and at its flanks. The velocity finestructure is organized in layers that align with layers in properties (salinity, temperature) but mostly cross through surfaces of constant density. The largest magnitude in velocity finestructure is seen between the surface and 140 m just outside the maximum mesoscale flow but also in a layer underneath the eddy centre, between 250 and 450 m. For both regions a cyclonic rotation of the velocity finestructure with depth suggests the vertical propagation of near-inertial wave (NIW) energy. Modification of the planetary vorticity by anticyclonic (eddy core) and cyclonic (eddy periphery) relative vorticity is most likely impacting the NIW energy propagation. Below the low oxygen core salt-finger type double diffusive layers are found that align with the velocity finestructure.Apparent oxygen utilization (AOU) versus dissolved inorganic nitrate (NO − 3 ) ratios are about twice as high (16) in the eddy core compared to surrounding waters (8.1). A large NO − 3 deficit of 4 to 6 µmol kg −1 is determined, rendering denitrification an unlikely explanation. Here it is hypothesized that the differences in local recycling of nitrogen and oxygen, as a result of the eddy dynamics, cause the shift in the AOU : NO − 3 ratio. High NO − 3 and low oxygen waters are eroded by mixing from the eddy core and entrain into the mixed layer. The nitrogen is reintroduced into the core by gravitational settling of particulate matter out of the euphotic zone. The low oxygen water equilibrates in the mixed layer by air-sea gas exchange and does not participate in the gravitational sinking. Finally we propose a mesoscalesubmesoscale interaction concept where wind energy, mediated via NIWs, drives nutrient supply to the euphotic zone and drives extraordinary blooms in anticyclonic mode-water eddies.

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A global algorithm for estimating Absolute Salinity

Cited by 128 publications

References 18 publications

Effect of Sediment Suspensions on Seawater Salinity Assessments

Effect of Sediment Suspensions on Seawater Salinity Assessments

Thermodynamic properties of seawater, ice and humid air: TEOS-10, before and beyond

Upwelling and isolation in oxygen-depleted anticyclonic modewater eddies and implications for nitrate cycling

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