Mechanisms of core-mantle angular momentum exchange and the observed spectral properties of torsional oscillations

摘要: [1] Torsional oscillations of the fluid core produce decadal variations in Earth's magnetic field and length day. The can be used to infer velocity oscillations. An additional constraint is imposed by length-of-day because coupling mechanisms are required transfer angular momentum between mantle. Proposed included electromagnetic, topographic, gravitational couplings. We make use a finite volume model core-mantle system evaluate each these with respect observed spectral properties torsional find that different have characters which may useful distinguishing their importance within system. For reasonable values mantle properties, inner candidate mechanism most likely able reproduce all features Possible spatial distributions oscillation excitation source also investigated.