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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