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| Titel |
A global comparison of Argo and satellite altimetry observations |
| VerfasserIn |
A.-L. Dhomps, S. Guinehut, P.-Y. Traon, G. Larnicol |
| 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. 2 ; Nr. 7, no. 2 (2011-03-10), S.175-183 |
| Datensatznummer |
250004533
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| Publikation (Nr.) |
 copernicus.org/os-7-175-2011.pdf |
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| Zusammenfassung |
| Differences, similarities and complementarities between Sea Level Anomalies
(SLA) deduced from altimeter measurements and dynamic height anomalies (DHA)
calculated from Argo in situ temperature (T) and salinity (S) profiles are
globally analyzed. SLA and DHA agree remarkably well and, compared to
previous studies, Argo dataset allows an improvement in the coherence
between SLA and DHA. Indeed, Argo data provides a much better spatial
coverage of all oceans and particularly the Southern Ocean, the use of an
Argo mean dynamic height, the use of measured salinity profiles (versus
climatological salinity), and the use of a deeper reference level (1000 m
versus 700 m). The large influence of Argo salinity observations on the
consistency between altimetry and hydrographic observations is particularly
demonstrated with an improvement of 35% (relative to the SLA minus DHA
signal) by using measured salinity profiles instead of climatological data.
The availability of observations along the Argo float trajectories also
provides a means to describe the sea level variability of the global ocean
both for the low frequency and the mesoscale part of the circulation.
Results indicate that sea level variability is dominated by baroclinic
signal at seasonal to inter-annual periods for all latitudes. In the
tropics, sea level variability is baroclinic for meso-scale to interannual
periods and at high latitudes, sea level variability is barotropic with also
deep baroclinic signals (i.e. influence of deep temperature and salinity
signals) for intra seasonal and mesoscale periods. These results emphasize
the need to separate the different time and space scales in order to improve
the merging of the two data sets. The qualitative study of seasonal to
interannual SLA minus DHA signals finally reveals signals related to deep
ocean circulation variations and basin-scale barotropic signals. Future work
is, however, needed to understand the observed differences and relate them
to different forcing mechanisms. |
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