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IERS Message No. 113                                       June 11, 2007
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Revision of IERS Earth Rotation Series from 14 June 2007


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

The precision of the techniques contributing to IERS earth orientation
series is continually improving. For many applications mostly linked to
space geodesy the consistency between the terrestrial reference frame
and EOP are required.

Based on the results of their analyses and the release of the ITRF2005,
the IERS decided to bring the consistency of its EOP series with the
International Reference Frames to a better level of accuracy.

The change on 14 June 2007 (MJD= 54265.0) will consist in 
   1) Biases of respectively about -100 and +300 microarseconds in pole
      components
   2) Small changes in UT1-TAI and celestial pole offsets

IERS EOP series (Bulletin A, Bulletin B, C01, C02, C04) will be
expressed in the new system for epochs starting with: 14 JUNE 2007,
0h UT (MJD=54265.0). IERS EOP series C 03 is no more updated.

New version of C 04 computed in the new system is now called
IERS 05 C 04.

IERS 05 C 04 series are avalaible at: 
ftp://hpiers.obspm.fr/iers/eop/eopc04_05

and a notice describing its characteristics is available at:
ftp://hpiers.obspm.fr/iers/eop/

Past version of C 04 can been still downloaded as long as necessary
from:
ftp://hpiers.obspm.fr/iers/eop/eopc04
http://hpiers.obspm.fr/eop-pc/products/combined/C04_05.guide.pdf

IERS EOP series recomputed in the new system will be available under the
following names.

|----------------------------------------------------------------------------|
|    Old name    | Time  |    New name       | start |        Comment        |
|                | resol.|                   | year  |                       |
|----------------|-----------------------------------|-----------------------|
|                |                           |       |                       |
| Bulletin A	 |  1d   | Bulletin A        | 1976  |New, homogeneous series|
| Bulletin B	 |  1d   | Bulletin B        | 1988  |Past values NOT revised|
|                |       |                   |       |                       |
| EOP(IERS) C 01 | .05yr | EOP(IERS) 05 C 01 | 1846  |Homogeneous series     |
|                |       |                   |       | recomputed since 1962 |
| EOP(IERS) C 02 |  5d   | EOP(IERS) 05 C 02 | 1962  |Past values NOT revised|
|                |       |                   |       |                       |
| EOP(IERS) C 03 |  1d   |                   |       |No more updated        |
|                |       |                   |       |                       |
| EOP(IERS) C 04 |  1d   | EOP(IERS) 05 C 04 | 1962  |New, homogeneous series|
|                |       |                   |       | recomputed since 1962 |
|                |       |                   |       |                       |
| EOP(IERS) C 04*|  1d   | EOP(IERS) 05 C 04*| 1962  |New, homogeneous series|
|                |       |                   |       | recomputed since 1962 |
|----------------------------------------------------------------------------|

EOP(IERS) 05 C 04* = EOP(IERS) 05 C 04 2000 where celestial pole
offsets are expressed in the IAU 2000
 
 
Thank you for your cooperation
 
D. Gambis and C. Bizouard, Earth Orientation Center, Paris Observatory
W. Wooden and B. Luzum, Rapid Service/Prediction Center, U.S. Naval 
Observatory


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