Observations have revealed the existence of a 6-year oscillation in the whole Earth system, from its deep interior to the superficial fluid envelopes. However, the origin of such a global phenomenon remains unknown. In this study we investigate the spatio-temporal structure of the 6-yr cycle of the atmospheric zonal wind circulation and inferred atmospheric angular momentum. These new findings should help understanding why and how such a 6-yr periodicity manifest across the whole Earth system.

To understand core dynamics, insight from several possible observables is needed. By applying several separation methods, we show spatiotemporal variabilities in the magnetic and gravity fields related to the core dynamics. A 7-year oscillation is found in all conducted analyses. The results in the magnetic field reflect the core processes and the variabilities in the gravity field exhibit new findings that might be an interesting input to build an enhanced model of the Earth’s core.

While a 6-year oscillation has been reported for some time in the motions of the fluid outer core of the Earth, in the magnetic field and in the Earth rotation, novel results indicate that the climate system also oscillates at this 6-year frequency. This strongly suggests the existence of coupling mechanisms affecting the Earth system as a whole, from the deep Earth interior to the surface fluid envelopes.