The Free Core Nutation(FCN)is a rotational mode caused by non-alignment of the rotation axis of the core and of the mantle.Its period observed by VLBI and superconducting gravimetry is around 430 sidereal days(Sd)with...The Free Core Nutation(FCN)is a rotational mode caused by non-alignment of the rotation axis of the core and of the mantle.Its period observed by VLBI and superconducting gravimetry is around 430 sidereal days(Sd)with precision of better than 1 Sd,while its“theoretical”period calculated by traditional approaches and a given Earth model ranges from 450 to 470 Sd.Their gap of about 30 Sd is significant compared with its observation precision.We propose a spectral element method to compute the period of FCN and obtain a period of 434 Sd which is very close to the observed value.展开更多
基金the National Natural Science Foundation of China(11973072/12233010).
文摘The Free Core Nutation(FCN)is a rotational mode caused by non-alignment of the rotation axis of the core and of the mantle.Its period observed by VLBI and superconducting gravimetry is around 430 sidereal days(Sd)with precision of better than 1 Sd,while its“theoretical”period calculated by traditional approaches and a given Earth model ranges from 450 to 470 Sd.Their gap of about 30 Sd is significant compared with its observation precision.We propose a spectral element method to compute the period of FCN and obtain a period of 434 Sd which is very close to the observed value.
