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| Titel |
Metrological traceability of oceanographic salinity measurement results |
| VerfasserIn |
S. Seitz, R. Feistel, D. G. Wright, S. Weinreben, P. Spitzer, P. Bièvre |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1812-0784
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| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 7, no. 1 ; Nr. 7, no. 1 (2011-01-19), S.45-62 |
| Datensatznummer |
250004430
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| Publikation (Nr.) |
 copernicus.org/os-7-45-2011.pdf |
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| Zusammenfassung |
| Consistency of observed oceanographic salinity data is discussed with
respect to contemporary metrological concepts. The claimed small uncertainty
of salinity measurement results traceable to the conductivity ratio of a
certified IAPSO Standard Seawater reference is not metrologically justified
if results are compared on climatic time scales. This applies in particular
to Practical Salinity SP, Reference Salinity SR, and the latest
estimates of Absolute Salinity using the TEOS-10 formalism. On climate time
scales an additional contribution to the uncertainty that is related to
unknown property changes of the reference material must be accounted for.
Moreover, when any of these measured or calculated quantity values is used
to estimate Absolute Salinity of a seawater sample under investigation,
another uncertainty contribution is required to quantify the accuracy of the
equations relating the actually measured quantity to the Absolute Salinity.
Without accounting for these additional uncertainties, such results cannot
be used to estimate Absolute Salinity with respect to the International
System of Units (SI), i.e. to the unit chosen for the mass fraction of
dissolved material in the sample, which is "g kg−1". From a metrological
point of view, such deficiencies in the calculations involving other
quantities will produce SI-incompatible results. We outline how these
problems can be overcome by linking salinity to primary SI measurement
standards. |
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