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Analysis of UTI determinations by VLBI within project IRIS

Published online by Cambridge University Press:  03 August 2017

H. Schuh
H. Schuh*
Affiliation:
Geodetic Institute, University of Bonn, Nussallee 17, D-5300 Bonn 1, FRG

Abstract

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Two series of UT1 data determined by VLBI within Project IRIS at 5 day intervals respectively on a daily basis have been subjected to an iterative spectral analysis. Various significant oscillations with periods less than two months could be detected in the IRIS UT1 data. Most of the periods between 18 and 63 days obviously correspond to short-period variations in global atmospheric data. The other significant variations with periods shorter than 35 days can be clearly identified as being due to the influence of zonal tides on the rotation of the earth. The results of the spectral analysis are compared with the theoretical periods and phases and with the amplitudes given by Yoder et al. (1981). The spectral analysis reveals very clearly the monthly (27.6d) and the fortnightly (13.7d) terms and also the smaller variations at 14.77 days and 9.13 days. A similar analysis of 8 subsets, each with two months of the daily UT1 determinations, indicates that the small 7.10 day term can already be extracted from the VLBI observations.

Type
III. Determination of Earth Rotation Parameters
Information
Symposium - International Astronomical Union , Volume 128: Earth's Rotation and Reference Frames for Geodesy and Geodynamics , 1988 , pp. 171 - 180
Copyright
Copyright © Reidel 1988 

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