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Snow-load excitation of the Earth's annual wobble

Published online by Cambridge University Press:  03 August 2017

B. Fong Chao ,
William P. O'Connor  and
Alfred T. C. Chang
B. Fong Chao
Affiliation:
Laboratory for Terrestrial Physics, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
William P. O'Connor
Affiliation:
Laboratory for Terrestrial Physics, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
Alfred T. C. Chang
Affiliation:
Laboratory for Terrestrial Physics, Goddard Space Flight Center, Greenbelt, Maryland 20771, USA

Abstract

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A global, monthly snow depth data set has been generated from weather satellite (Nimbus 7) observations using passive microwave remote-sensing techniques. In this paper we analyzed five years of data, 1980–1984, to compute the snow-load excitation of the annual wobble of the Earth's rotation axis. A uniform sea-level decrease has been assumed in order to conserve water mass. The result shows dominant seasonal cycles. The prograde component of the annual excitation is Ψ+ = (5.0 milliarcsec, −110*) and the retrograde component Ψ− = (5.0 milliarcsec, −31*). These computed values are compared with previous groundwater estimates, as well as the inferred values from ILS and LAGEOS polar motion measurements. The importance of accurate data is stressed and future plans proposed.

Type
VI. Causes of Variations in Earth Rotation Parameters
Information
Symposium - International Astronomical Union , Volume 128: Earth's Rotation and Reference Frames for Geodesy and Geodynamics , 1988 , pp. 373 - 380
Copyright
Copyright © Reidel 1988 

References

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