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Atmospheric Angular Momentum and the Length of Day1

Published online by Cambridge University Press:  12 April 2016

R. B. Langley
Affiliation:
Massachusetts Institute of Technology Cambridge, MA 02139 U.S.A.
R. W. King
Affiliation:
Massachusetts Institute of Technology Cambridge, MA 02139 U.S.A.
I. I. Shapiro
Affiliation:
Massachusetts Institute of Technology Cambridge, MA 02139 U.S.A.
R. D. Rosen
Affiliation:
Environmental Research and Technology, Inc. Concord, MA 01742 U.S.A.
D. A. Salstein
Affiliation:
Environmental Research and Technology, Inc. Concord, MA 01742 U.S.A.

Abstract

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We have used lunar laser ranging (LLR) observations from the McDonald Observatory in conjunction with pole positions from the Bureau International de l’Heure (BIH) to determine the length of day (l.o.d.) at five-day intervals over the period 1971 through 1979. We compared the changes in these l.o.d. values to those inferred from determinations of the angular momentum of the global atmosphere, for the years 1976-1979, computed from twice-daily analyses of the zonal wind. These latter analyses were carried out by the National Meteorological Center, Camp Springs, MD. In both the observed (LLR) and the inferred (meteorological) values of changes in l.o.d., we have identified the near 50-day oscillation recently noted by Feissel and Gambis at the BIH. For the period of overlapping dates, the two oscillations agree closely in both amplitude and phase. The typical amplitude is about 0.2 milliseconds or approximately half the amplitude of the annual and semiannual variations in l.o.d.

Type
Part II
Copyright
Copyright © Reidel 1982

Footnotes

2

Present address: Department of Surveying Engineering, University of New Brunswick, Fredericton, N.B. E3B 5A3, Canada.

1

This paper has been submitted to the journal Nature under the title “Atmospheric Angular Momentum and the Length of Day: A Common Fluctuation with a Period Near 50 Days.”

References

1 This paper has been submitted to the journal Nature under the title “Atmospheric Angular Momentum and the Length of Day: A Common Fluctuation with a Period Near 50 Days.”