Assessing ocean-model sensitivity to wind forcing uncertainties

Isabel Andreu-Burillo (1, 2) , Guy Caniaux (1) , Michel Gavart (3) , Pierre de Mey (4) , Rémy Baraille (5)

1 CNRM - Centre national de recherches météorologiques
2 GMGEC - Groupe de Météorologie de Grande Échelle et Climat
3 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
4 ECOLA - Echanges Côte-Large
5 SHOM - Service Hydrographique et Océanographique de la Marine

In this paper, we assess the short-term forecast error of a mesoscale primitive-equation open-ocean model, induced by uncertainties in wind forcing. Statistics calculated from an ensemble of ocean states show that temperature forecast error is strongest at the top of the ensemble-mean thermocline, as a consequence of vertical displacement of the mixed-layer base around its ensemble mean. Horizontal pattern of the temperature error in the mixed-layer is mainly explained by horizontal advection and surface heat flux fluctuations. These two mechanisms and entrainment through the mixed-layer bottom are presented as the three processes responsible for thermal forecast error growth in the modeled upper ocean.

Mots clés: General circulation models; Numerical simulation; Forecasting; Growth of error; Entrainment; Fluctuations; Heat transfer; Error; Mixed layer; Thermocline; Primitive equation; Mesoscale; Short term; Uncertainty; Forcing; Wind effect; Ocean model

Domaines: Océanographie

Isabel Andreu-Burillo, Guy Caniaux, Michel Gavart, Pierre de Mey, Rémy Baraille. Assessing ocean-model sensitivity to wind forcing uncertainties. Geophysical Research Letters, 2002, 29, pp.5.1-5.4. ⟨10.1029/2001GL014473⟩. ⟨hal-00764350⟩