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| Titel |
High resolution 3-D temperature and salinity fields derived from in situ and satellite observations |
| VerfasserIn |
S. Guinehut, A.-L. Dhomps, G. Larnicol, P.-Y. Traon |
| 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 ; 8, no. 5 ; Nr. 8, no. 5 (2012-10-09), S.845-857 |
| Datensatznummer |
250005873
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| Publikation (Nr.) |
 copernicus.org/os-8-845-2012.pdf |
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| Zusammenfassung |
| This paper describes an observation-based approach that efficiently combines
the main components of the global ocean observing system using statistical
methods. Accurate but sparse in situ temperature and salinity profiles
(mainly from Argo for the last 10 yr) are merged with the lower accuracy but
high-resolution synthetic data derived from satellite altimeter and sea
surface temperature observations to provide global 3-D temperature and
salinity fields at high temporal and spatial resolution. The first step of
the method consists in deriving synthetic temperature fields from altimeter
and sea surface temperature observations, and salinity fields from altimeter
observations, through multiple/simple linear regression methods. The second
step of the method consists in combining the synthetic fields with in situ
temperature and salinity profiles using an optimal interpolation method.
Results show the revolutionary nature of the Argo observing system. Argo
observations now allow a global description of the statistical relationships
that exist between surface and subsurface fields needed for step 1 of the
method, and can constrain the large-scale temperature and mainly salinity
fields during step 2 of the method. Compared to the use of climatological
estimates, results indicate that up to 50% of the variance of the
temperature fields can be reconstructed from altimeter and sea surface
temperature observations and a statistical method. For salinity, only about
20 to 30% of the signal can be reconstructed from altimeter
observations, making the in situ observing system essential for salinity
estimates. The in situ observations (step 2 of the method) further reduce the
differences between the gridded products and the observations by up to
20% for the temperature field in the mixed layer, and the main
contribution is for salinity and the near surface layer with an improvement
up to 30%. Compared to estimates derived using in situ observations
only, the merged fields provide a better reconstruction of the high
resolution temperature and salinity fields. This also holds for the
large-scale and low-frequency fields thanks to a better reduction of the
aliasing due to the mesoscale variability. Contribution of the merged fields
is then illustrated to describe qualitatively the temperature variability
patterns for the period from 1993 to 2009. |
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