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Science 17 January 1992:
Vol. 255. no. 5042, pp. 321 - 324
DOI: 10.1126/science.255.5042.321
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Articles

The Earth's Angular Momentum Budget on Subseasonal Time Scales

J. O. DICKEY 1, S. L. MARCUS 1, J. A. STEPPE 1, and R. HIDE 2

1 Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Pasadena, CA 91109
2 Robert Hooke Institute, The Observatory, Clarendon Laboratory, Parks Road, Oxford OX1 3PU, England, U.K.

Irregular length of day (LOD) fluctuations on time scales of less than a few years are largely produced by atmospheric torques on the underlying planet. Significant coherence is found between the respective time series of LOD and atmospheric angular momentum (AAM) determinations at periods down to 8 days, with lack of coherence at shorter periods caused by the declining signal-to-measurement noise ratios of both data types. Refinements to the currently accepted model of tidal Earth rotation variations are required, incorporating in particular the nonequilibrium effect of the oceans. The remaining discrepancies between LOD and AAM in the 100- to 10-day period range may be due to either a common error in the AAM data sets from different meteorological centers, or another component of the angular momentum budget.

Submitted on August 16, 1991
Accepted on October 30, 1991


THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:
Detection and Modeling of Nontidal Oceanic Effects on Earth's Rotation Rate.
S. L. Marcus, Y. Chao, J. O. Dickey, and P. Gegout (1998)
Science 281, 1656-1659
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