1

Niveau de mer et masses d’eaux simulées par les Océans forcés: un premier bilan des problèmes entre satellites et OGCMs

R. Bourdalle-Badie (Mercator Océan)C. Cassou (Cerfacs)N. Ferry (Mercator Océan)MH Rio (CLS) The Drakkar group

2

Vents diffusiométriques versusvents issus de d’analyses météorologiques

Vents diffusiométriques:

CORE2: issu de la réanalyse NCEP2, mais la moyenne climatologique et le cycle saisonnier proviennent de Quickscat

Vents issu d’analyses / réanalyses météorologiques:

ERA-Interim : assimilation de vents diffusiométriques mais contrainte forte de la physique du modèle atmosphérique

Le vent est un forçage clé de la dynamique océanique, surtout dans les tropiques.

Impact fort sur la surface moyenne de l’océan (MDT)

3

Mean Dynamic Topography GOCE-TIMR3 :MSS CNES-CLS11 minus EGM-TIM-R3 MDT

MDT accuracy is close 1~2 cm , largest errors< 5 cm in most areas

MDT= imprint of the ocean circulation

4

Impact of CORE2 forcing on the MDT

MDT difference:

ORCA1 forced by CORE2 minus GOCE-TIMR3

45°S-45°N average of the MDT difference is 0

NEMO ORCA1° MDT:1993-2007 averagesimulation (C. Cassou, Cerfacs)

545°S-45°N average of the MDT difference is 0

Impact of ERA-Interim forcing on the MDT

NEMO ORCA1° MDT:1993-2007 averagesimulation (C. Cassou, Cerfacs)

MDT difference:

ORCA1 forced by ERA-Interim minus GOCE-TIMR3

6

MDT difference:

ORCA1/12° forced by CORE2 minus GOCE-TIMR3

45°S-45°N average of the MDT difference is 0

NEMO ORCA1/12° MDT:1998-2007 average.simulation byDrakkar group(M. Scheinert, IfM Kiel)

Impact of CORE2 forcing on the MDT

745°S-45°N average of the MDT difference is 0

NEMO ORCA1/12° MDT1998-2007 averageSimulation by Drakkar group(B. Barnier, JM MolinesLEGI Grenoble)

Impact of ERA-Interim forcing on the MDT

MDT difference:

ORCA1/12° forced by ERA-Interim minus GOCE-TIMR3

8

Difference

ORCA1/12° CORE2 - ORCA1/12° ERA-Interim

45°S-45°N average of the MDT difference is 0

1998-2007 averageNEMO ORCA1/12°simulation Drakkar groupIfM KielLEGI, Grenoble

Impact of CORE2 / ERA-Interim forcing on the MDT

cm

9

Impact of CORE2 on the MDT

MDT POP 1° forced by CORE2 – Maximenko / Niiler MDT

NCAR simulation

cm

10

Impact of CORE2 / ERA-Interim on water masses

Temperature difference with LEVITUS at 100m

CORE2

ERA-Interim1993-2007

average

11

Impact of CORE2 / ERA-Interim on water masses

Temperature difference with LEVITUS at 300m

CORE2

ERA-Interim1993-2007

average