Excitation of Free Core Nutation by geophysical fluids

The Earth’s free core nutation (FCN) is a rotation mode sourced of core-mantle boundary. The observed FCN signal from VLBI measurements shows apparent fluctuations in period, phase and amplitude. We study the excitation of FCN by the atmospheric and oceanic Effective Angular Momentum Functions time series from different geophysical models. And part of Hydrological Angular Momentum Functions is considered. Compared with the observed FCN, the excited signal shows different consistency over time. The contribution of different geophysical fluids is also discussed.