Retrograde free core nutation
Free core nutation at these plots was obtained by subtracting the fit
to 229 nutation terms to the nutation series gsf2003d. Signal at angular
frequencies [-190, -72] nrad/sec was removed from the empirical nutation
expansion. Thus, these residuals contains noise and the signal at the band
[-190, -72] nrad/sec. Only points with formal uncertainties less than
0.3 nrad for the period of 1991-1993 and 0.2 nrad for the period of
1993.0-2003.6 were used. Units are nanoradians ( 1 nrad = 0.2 mas ).
Free core nutation as a function of time
Empirical transfer function
Blue -- empirical transfer function from
solution nut_15c;
Green -- MHB2000 transfer function as
a reference.
The Earth orientation series 2003d.eob with
respect to Wahr80 nutation theory.
The Earth orientation series
2003d_mhb2000.eob with respect to MHB2000
nutation expansion.
Format description.
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Last update: 10-SEP-2003 19:24:15
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Leonid Petrov