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Predictability of the Earth's polar motionA comprehensive, experimental study of the predictability of the polar motion using a homogeneous BIH (Bureau International de l'Heure) data set is presented. Based on knowledge of the physics of the annual and the Chandler wobbles, the numerical model for the polar motion is constructed by allowing the wobble periods to vary. Using an optimum base length of 6 years for prediction, this floating-period model, equipped with a non-linear least-squares estimator, is found to yield polar motion predictions accurate from 0.012 to 0.024 inches depending on the prediction length up to one year, corresponding to a predictability of 91-83%. This represents a considerable improvement over the conventional fixed-period predictor, which does not respond to variations in the apparent wobble periods. The superiority of the floating-period predictor to other predictors based on critically different numerical models is also demonstrated.
Document ID
19840015923
Acquisition Source
Legacy CDMS
Document Type
Technical Memorandum (TM)
Authors
Chao, B. F. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 4, 2013
Publication Date
April 1, 1984
Subject Category
Earth Resources And Remote Sensing
Report/Patent Number
NASA-TM-86095
NAS 1.15:86095
Accession Number
84N23991
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

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