American Geophysical Union Become an AGU Member
Subscribe to AGU Journals		 AGU Home AGU Publications

Read Full Article (file size: 1946158 bytes)    Cited by

JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 109, B03408, doi:10.1029/2003JB002817, 2004

Low-frequency excitation of length of day and polar motion by the atmosphere

Olivier de Viron

Royal Observatory of Belgium, Brussels, Belgium


David Salstein

Atmospheric and Environmental Research, Inc., Lexington, Massachusetts, USA


Christian Bizouard

Observatoire de Paris, Systèmes of Référence Temps Espace, Paris, France


Laura Fernandez

Consejo de Investigaciones Cientficas y Técnicas, Facultad de Ciencias Astronomicas y Geofisicas, Buenos Aires, Argentina


Abstract

Results of a 100-year run of the Hadley Centre general circulation model are used to compute monthly values of the three components of atmospheric torque on the Earth and of the associated atmospheric angular momentum series. All these results are compared with equivalent ones from the National Center for Environmental Prediction/National Center for Atmospheric Research reanalyses for the overlap period since 1948. We find some important differences; consequently, our results should be taken as an order of magnitude of the effect. We also compute the effect of the atmosphere on length of day (LOD) and polar motion by the use of both the torque and the angular momentum approaches. We find comparable amplitude with both torque and angular momentum for the polar motion; the axial torque, however, related to LOD, appears to be unphysical. The excitation of long-period LOD variation is in phase with the observed variation but much smaller. The low-frequency polar motion is only coherent with the observation at certain particular periods.

Received 30 September 2003; accepted 16 January 2004; published 19 March 2004.

Index Terms: 1223 Geodesy and Gravity: Ocean/Earth/atmosphere interactions (3339); 1239 Geodesy and Gravity: Rotational variations; 3339 Meteorology and Atmospheric Dynamics: Ocean/atmosphere interactions (0312, 4504).

Read Full Article (file size: 1946158 bytes)    Cited by

Citation: de Viron, O., D. Salstein, C. Bizouard, and L. Fernandez (2004), Low-frequency excitation of length of day and polar motion by the atmosphere, J. Geophys. Res., 109, B03408, doi:10.1029/2003JB002817.