Richard S. Gross and T. Mike Chin, JPL/CalTech
Angular momentum is a fundamental conserved property of dynamical systems. It is an integrated measure of mass motion and redistribution and as such can be used to diagnose the oceans' changing general circulation. Furthermore, the angular momentum of the oceans is exchanged with that of the solid Earth causing the Earth's rotation to change. In fact, a number of studies have recently shown the importance of oceanic processes in causing Earth rotation changes, particularly in exciting polar motion, which is the motion of the rotation pole with respect to the Earth's crust. Because of this demonstrated importance of oceanic processes in exciting polar motion, polar motion observations have the potential to be used as a novel means of testing ocean models. This potential is illustrated here by comparing the oceanic angular momentum computed from two different runs of the HYCOM ocean model to polar motion excitation observations from which atmospheric effects have been removed.