Contribution of oceanic and atmospheric excitations to the Chandler wobble

By using the data sets of the oceanic and atmospheric angular momentum during 1985 similar to 1995, the mean energy of the oceanic and atmospheric excitation in Chandler wobble band (CWB) is estimated and compared with that of the geodetically observed excitation. Results show that the variation of the oceanic angular momentum (OAM) can provide about 64 % of the excitation energy in CWB with a dominant contribution of the oceanic bottom pressure, while the excitation energy provided by the atmospheric angular momenta (AAM (NCEP/NCAR) and AAM(JMA)) is about 23 % and 214 % in comparison with the observed one. Squared coherence, 0.52 (0.32 and 0.37), is also estimated between the observed excitation and the OAM (AAM (NCEP/NCAR) and AAM(JMA)) excitations. Coherent phases show a lagging phase about 19degrees for OAM excitation, leading phases about 47degrees for AAM(NCEP/NCAR) and 19degrees for AAM(JMA), relative to the observed excitation, respectively. Analyses of some shorter (9 and 6 yrs.) and longer ( 16 and 39 yrs.) data series indicate that either the excitation energy, or the squared coherence are temporally variable, and their variability are of, in some extent, stochastic property.