Article| Any: | 2016 |
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| Autor(s): | M. Hamon, J. Beuvier, S. Somot, J.-M. Lellouche, E. Greiner, G. Jordà, M.-N. Bouin, T. Arsouze, K. Béranger, F. Sevault, C. Dubois, M. Drevillon, Y. Drillet |
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| Títol: | Design and validation of MEDRYS, a Mediterranean Sea reanalysis over the period 1992–2013 |
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| Revista: | Ocean Science |
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| ISSN: | 1812-0784 |
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| JCR Impact Factor: | 2.821 |
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| Volum: | 12 |
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| Pàgines: | 577-599 |
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| D.O.I.: | 10.5194/os-12-577-2016 |
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| Web: | https://www.ocean-sci.net/12/577/2016/ |
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| Resum: | The French research community in the
Mediterranean Sea modeling and the French operational ocean forecasting
center Mercator Océan have gathered their skill and expertise in
physical oceanography, ocean modeling, atmospheric forcings and data
assimilation to carry out a MEDiterranean sea ReanalYsiS (MEDRYS) at
high resolution for the period 1992–2013. The ocean model used is
NEMOMED12, a Mediterranean configuration of NEMO with a 1∕12° ( ∼ 7 km)
horizontal resolution and 75 vertical z levels with partial
steps. At the surface, it is forced by a new atmospheric-forcing data
set (ALDERA), coming from a dynamical downscaling of the ERA-Interim
atmospheric reanalysis by the regional climate model ALADIN-Climate with
a 12 km horizontal and 3 h temporal resolutions. This configuration is
used to carry a 34-year hindcast simulation over the period 1979–2013
(NM12-FREE), which is the initial state of the reanalysis in
October 1992. MEDRYS uses the existing Mercator Océan data assimilation
system SAM2 that is based on a reduced-order Kalman filter with a
three-dimensional (3-D) multivariate modal decomposition of the forecast
error. Altimeter data, satellite sea surface temperature (SST) and
temperature and salinity vertical profiles are jointly assimilated. This
paper describes the configuration we used to perform MEDRYS. We then
validate the skills of the data assimilation system. It is shown that
the data assimilation restores a good average temperature and salinity
at intermediate layers compared to the hindcast. No particular biases
are identified in the bottom layers. However, the reanalysis shows
slight positive biases of 0.02 psu and 0.15 °C above 150 m depth. In the
validation stage, it is also shown that the assimilation allows one to
better reproduce water, heat and salt transports through the Strait of
Gibraltar. Finally, the ability of the reanalysis to represent the sea
surface high-frequency variability is shown. |
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