Sensitivity of the meridional transport in a 1.5-layer ocean model to localized mass sources
Résumé
The response of a 1.5-layer ocean model forced by localized stochastic mass sources is studied. The focus is on the sensitivity of the spectral characteristics of the meridional transport to the location and the extent of the source region. In all the experiments, performed in hemispheric and interhemispheric basins, the spectra show a peak at interannual time scale revealing the existence of an oscillation. The period of the oscillation is defined by the zonal extent of the forcing, whereas its amplitude is affected by its location. When the source region is located in the northwestern corner of the basin, the peak emerges clearly on the spectrum of the meridional transport, whereas it is strongly reduced when the source region is located in open ocean. The extension to an inter-hemispheric basin increases the energy at the period of the oscillation, but the introduction of the equatorial dynamics does not affect the spectral characteristics of the response for periods longer than 1 year.