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Origin of the 30–60 Day Oscillation in the LOD and Atmospheric Angular Momentum: New Findings from the UCLA General Circulation Model

  • S. L. Marcus
  • M. Ghil
  • J. O. Dickey
  • T. M. Eubanks
Part of the International Association of Geodesy Symposia book series (IAG SYMPOSIA, volume 105)

Abstract

Significant 30-60 day oscillations have been detected in both length-of-day (LOD) and atmospheric angular momentum (AAM) data sets. This study examines AAM fluctuations arising in a numerical simulation of the global atmosphere, performed with the UCLA General Circulation Model. A strong 30–60 day AAM (zonal wind) oscillation is found in the NH extratropics of the model, associated with periodic blocking over the northeast Pacific and Atlantic oceans. A coupled, zonally-symmetric mass redistribution leads to coherent fluctuations in the atmosphere’s moment of inertia. No intraseasonal oscillations are found in an experiment with surface elevations set to zero, suggesting an orographic origin of the extratropical 30–60 day AAM oscillation.

Keywords

Zonal Wind Empirical Orthogonal Function Earth Rotation Intraseasonal Oscillation Global Atmosphere 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag New York Inc. 1990

Authors and Affiliations

  • S. L. Marcus
    • 1
    • 2
  • M. Ghil
    • 2
    • 1
  • J. O. Dickey
    • 1
  • T. M. Eubanks
    • 1
  1. 1.Jet Propulsion LaboratoryCalifornia Institute of TechnologyPasadenaUSA
  2. 2.Department of Atmospheric Sciences and Institute of Geophysics and Planetary PhysicsUniversity of CaliforniaLos AngelesUSA

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