 |
| Titel |
A model for predicting changes in the electrical conductivity, practical salinity, and absolute salinity of seawater due to variations in relative chemical composition |
| VerfasserIn |
R. Pawlowicz |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1812-0784
|
| Digitales Dokument |
URL |
| Erschienen |
In: Ocean Science ; 6, no. 1 ; Nr. 6, no. 1 (2010-03-18), S.361-378 |
| Datensatznummer |
250003365
|
| Publikation (Nr.) |
 copernicus.org/os-6-361-2010.pdf |
|
|
|
|
|
| Zusammenfassung |
| Salinity determination in seawater has been carried out for almost 30 years
using the Practical Salinity Scale 1978. However, the numerical value of
so-called practical salinity, computed from electrical conductivity, differs
slightly from the true or absolute salinity, defined as the mass of dissolved
solids per unit mass of seawater. The difference arises because more recent
knowledge about the composition of seawater is not reflected in the
definition of practical salinity, which was chosen to maintain historical
continuity with previous measures, and because of spatial and temporal
variations in the relative composition of seawater. Accounting for these
spatial variations in density calculations requires the calculation of a correction
factor δSA, which is known to range from 0 to
0.03 g kg−1 in the world oceans. Here a mathematical model relating
compositional perturbations to δSA is developed, by
combining a chemical model for the composition of seawater with a
mathematical model for predicting the conductivity of multi-component aqueous
solutions. Model calculations for this estimate of δSA,
denoted δSRsoln, generally agree with estimates
of δSA based on fits to direct density measurements,
denoted δSRdens, and show that biogeochemical
perturbations affect conductivity only weakly. However, small systematic
differences between model and density-based estimates remain. These may arise
for several reasons, including uncertainty about the biogeochemical processes
involved in the increase in Total Alkalinity in the North Pacific,
uncertainty in the carbon content of IAPSO standard seawater, and uncertainty
about the haline contraction coefficient for the constituents involved in
biogeochemical processes. This model may then be important in constraining
these processes, as well as in future efforts to improve parameterizations
for δSA. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|