Conservative Tracers and the Ocean Circulation

Inclusion of chemical tracers in inverse schemes for calculating the ocean circulation leads to a better determined system of constraints to the flow and may result in increased knowledge about mixing processes as well as current systems. A type of tracer suggested by Broecker, namely a conservative combination of nitrates or phosphates and oxygen (`NO' or `PO') uses standard observed quantities. It is shown that although these tracers do add information to more conventional inverse schemes, the present sampling strategy is inadequate for determining the ocean circulation quantitatively. The principal reasons for this are the variability of the ocean and the limited spatial coverage of present hydrographic surveys.