The dynamics of variability in the system ocean-atmosphere on decadal and interdecadal timescales are investigated in this subproject. In particular, the response of the oceanic circulation to changes in surface fluxes is examined with the aid of long-term integrations and sensitivity experiments of numerical models of the North Atlantic.
Special emphasis is placed on the subpolar regions where deep cold watermasses are formed.
The influence of these changes on oceanic CO 2 -transport is another objective of this subproject. Mesoscale eddies are not resolved in this model, due to computational costs for the long-term integrations, their influence on the mean circulation is parameterized by recently developed new mixing schemes. Various response and sensitivity experiments has been carried out so far, in order to determine the spatial and temporal characteristics of long-term variablility and to identify relevant mechanismen.