G04 Earth Rotation and Geodynamics

IAG (Geodesy)

29-Jun-2015, 16:30 - 18:00

Abstract content:

Multichannel Singular Spectrum Analysis of the Axial Atmospheric Angular Momentum

Earth's variable rotation is mainly produced by the variability of the Atmospheric Angular Momentum (AAM). In particular, the axial AAM component, 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) 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.

L. Zotov1,2, N.S. Sidorenkov2, C.K. Shum3.
1Sternberg Astronomical Institute- Lomonosov Moscow State University, Laboratory of gravimetry, Moscow, Russia.
2Hydro-Meteorological Center of Russia, Global Atmospheric Circulation Laboratory, Moscow, Russia.
3School of Earth Sciences- The Ohio State University-, Division of Geodetic Science, Columbus, USA.


AAM     MSSA     ENSO     LOD