Geology Reference
In-Depth Information
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Figure 4.18 Ring down of the prograde free core nutation (PFCN).
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Figure 4.19 Ring down of the retrograde free core nutation (RFCN).
4.4.4 Geometry of the free core nutations and wobbles
Even in realistic Earth models, the free core nutations are closely rigid-body rota-
tions of the fluid outer core with respect to the nearly stationary mantle and crust
(shell) (Jiang, 1993; Smylie and Jiang, 1993). In the Earth frame, both the prograde
free core nutation (PFCN) and the retrograde free core nutation (RFCN) involve
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