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Regular version of the site

Article

Multichannel singular spectrum analysis of the axial atmospheric angular momentum

Geodesy and Geodynamics. 2017. No. 8. P. 433-442.
Zotov L., Sidorenkov N., Bizouard C., Shum C., Shen W.

Earth's variable rotation is mainly produced by the variability of the atmospheric angular momentum (AAM). In particular, the axial AAM component χ3, which undergoes especially strong variations, induces changes in the Earth's rotation rate. In this study we analysed maps of regional input into the effective axial AAM from 1948 through 2011 from NCEP/NCAR reanalysis. Global zonal circulation patterns related to the length of day (LOD) were described. We applied Multichannel Singular Spectrum Analysis (MSSA) jointly to the mass and motion components of AAM, which allowed us to extract annual, semiannual, 4-month, quasi-biennial, 5-year, and low-frequency oscillations. Principal components (PCs) strongly related to El Nino southern oscillation (ENSO) were released. They can be used to study ENSO-induced changes in pressure and wind fields and their coupling to LOD. The PCs describing the trends have captured slow atmospheric circulation changes possibly related to climate variability.