| The origin of the decadal variability in the North Atlantic Ocean is investigated in a series of coupled and ocean-only numerical experiments. Two versions of the IPSL-CM5A model are considered, differing only by their atmospheric horizontal resolution (3.75 degrees x1.87 degrees and 2.5 degrees x1.25 degrees). When the ocean model is forced by the climatological surface fluxes from the low atmospheric resolution coupled model version, a 20-year variability emerges, similar to the variability found in the coupled simulation. Such decadal variability is consistent with a large-scale baroclinic instability of the mean flow in the west European basin. Increasing the atmospheric resolution leads to a more intense Icelandic low, which intensifies the western... |
