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| Titel |
Toward a multivariate reanalysis of the North Atlantic Ocean biogeochemistry during 1998-2006 based on the assimilation of SeaWiFS chlorophyll data |
| VerfasserIn |
C. Fontana, P. Brasseur, J.-M. Brankart |
| 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 ; 9, no. 1 ; Nr. 9, no. 1 (2013-01-16), S.37-56 |
| Datensatznummer |
250017450
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| Publikation (Nr.) |
 copernicus.org/os-9-37-2013.pdf |
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| Zusammenfassung |
| Today, the routine assimilation of satellite data into operational models of
ocean circulation is mature enough to enable the production of global
reanalyses describing the ocean circulation variability during the past
decades. The expansion of the "reanalysis" concept from ocean physics to
biogeochemistry is a timely challenge that motivates the present study. The
objective of this paper is to investigate the potential benefits of
assimilating satellite-estimated chlorophyll data into a basin-scale
three-dimensional coupled physical–biogeochemical model of the North
Atlantic. The aim is on the one hand to improve forecasts of ocean
biogeochemical properties and on the other hand to define a methodology for
producing data-driven climatologies based on coupled physical–biogeochemical
modeling. A simplified variant of the Kalman filter is used to assimilate
ocean color data during a 9-year period. In this frame, two experiments
are carried out, with and without anamorphic transformations of the state
vector variables. Data assimilation efficiency is assessed with respect to
the assimilated data set, nitrate of the World Ocean Atlas database and a
derived climatology. Along the simulation period, the non-linear
assimilation scheme clearly improves the surface analysis and forecast
chlorophyll concentrations, especially in the North Atlantic bloom region.
Nitrate concentration forecasts are also improved thanks to the assimilation
of ocean color data while this improvement is limited to the upper layer of
the water column, in agreement with recent related literature. This feature
is explained by the weak correlation taken into account by the assimilation
between surface phytoplankton and nitrate concentrations deeper than 50
meters. The assessment of the non-linear assimilation experiments indicates
that the proposed methodology provides the skeleton of an assimilative
system suitable for reanalyzing the ocean biogeochemistry based on ocean
color data. |
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