Quantifying the correlation between the MEI and LOD variations by decomposing LOD with Singular Spectrum Analysis

Paper i proceeding, 2014

Variations in the temporal length-of-day (LOD) contain information on phenomena related to the continuous evolution of Earth processes: tidal energy dissipation and core-mantle coupling (decadal, secular), meteorological and solar-lunar tide effects (annual, semi-annual). In this work, we studied an LOD time series obtained from VLBI measurements and extracted its principal components using the Singular Spectrum Analysis (SSA). After removing the long-term trend which explains 73. 8% of the signal, three remaining components explain a further 22. 0% of the signal: an annual and a semi-annual signals as well as a second trend. We compared the Multivariate ENSO index (MEI) with the variations in the amplitudes of the annual and semi-annual components and with the second trend. The correlations are significant: 0. 58 for the annual component, − 0. 48 for the semi-annual component and 0. 46 for the second trend.