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| Titel |
Metrology for ocean salinity and acidity- the European Metrology Research Project ENV05 |
| VerfasserIn |
Petra Spitzer, Steffen Seitz, Simona Lago, Daniela Stoica, Michal Mariassy, Robert Clough, Maria Filomena Camões |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075952
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| Zusammenfassung |
| An overview and status report on the EMRP (European Metrology Research Project)
“Metrology for ocean salinity and acidity” will be given. The project has been started in
September 2011. The consortium consists of partners from ten European metrology institutes
and two universities.
Need for the project
The project covers the thermodynamic quantities salinity, conductivity, density, speed
of sound, and temperature, and the chemical quantities pH, oxygen content and
composition.
It aims to develop methods, standards and tools to improve the databases used for climate
models. Measurement standards with well characterized uncertainties will enable calibration
of in-situ observing sensor networks and satellite systems traceable to SI units. The results
will improve the metrological infrastructure required for a reliable monitoring and modelling
of ocean processes. This will allow scientists to measure more accurately small changes in
long-term oceanographic data series.
Expected results and potential impact
The basis for data at higher pressure of up to 70 MPa and in a temperature range between
0 Ë C and 40 Ë C for the Equation of State will be improved by measurements of density,
salinity and speed of sound.
A novel primary conductivity sensor which can be used at high pressure will be
developed, tested and linked to primary improved density measurements at the same high
pressure. Improved and robust speed of sound measurement data for both high accuracy
laboratory and in situ measurements of seawater, will provided by means of an ultrasonic
double-reflector pulse-echo overlap technique. This also includes improved temperature
measurements with an uncertainty of 5 mK.
The determination of dissolved oxygen measurement methods will be optimised for the
special requirements of seawater. A reduction of the uncertainty by a least a factor of three is
anticipated.
Harmonised pH measurement procedures will be provided to underpin the traceability of
the pH data of seawater. The development of a primary potentiometric pH procedure at
higher ionic strength will allow the characterization of artificial seawater of reference
composition which will be suitable as calibration standard for spectrophotometric pH
measurements.
A validated method for the quantification of the mass fraction of strontium based on
isotope dilution mass spectrometry (ID-ICP-MS) will be developed. Analytical procedures
for the quantification of nutrients in seawater will be developed taking into account matrix
contributions.
More accurate methodologies for the determination of iron in seawater will be developed.
Confidence in quantification will be achieved by rigorous validation (covering sampling and
sample treatment), including thorough uncertainty budgeting and the comparison between
shipboard methods and ID-ICP-MS. |
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