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IERS Message No. 180                                    January 07, 2011
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Revision of IERS Earth Rotation Series effective 1 February 2011


The current series of IERS Earth Orientation Parameters (EOP) provides
the official transformation between the International Celestial
Reference Frame (ICRF) and the International Terrestrial Reference Frame
(ITRF).

In order to be consistent with the recently released ITRF2008, the IERS
EOP C04 is being revised. The new solution 08C04 is the reference
solution starting on 1 February 2011. Relative to 05C04, changes in the
EOP series consist of

   1) A negligible bias in x-pole and a bias of about -50 +/- 25
      microarcseconds in y-pole in the sense of y (08C04) - y (05C04);

   2) Changes in UT1-TAI and celestial pole offsets are respectively on
      the order of 2 microseconds, 1, and 17 microarcseconds which are
      at the level of the WRMS between IVS individual solutions.

Other IERS EOP series (Bulletin B, C01) will be expressed in this new
system consistent with ITRF2008 starting with solutions after 1 February
2011.

The Rapid Service/Prediction Center solutions (Bulletin A and daily)
will be expressed in the new system starting with solutions made on
1 February 2011.

The new version of the C 04 computed in the new system is now called
IERS 08 C 04.

IERS 08 C 04 series will be available at:
ftp://hpiers.obspm.fr/iers/eop/eopc04

A notice describing its characteristics will be available at:
ftp://hpiers.obspm.fr/iers/eop/eopc04/C04.guide.pdf

Past version of C 04 can be downloaded until 30 June 2011 from:
ftp://hpiers.obspm.fr/iers/eop/eopc04_05/


Thank you for your cooperation
 
D. Gambis, C. Bizouard, Earth Orientation Center,
     Paris Observatory
B. Luzum, N. Stamatakos, IERS Rapid Service/Predictions Center,
     US Naval Observatory


Please note: This is a corrected version of IERS Message No. 180
distributed on January 5, 2011.


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