# C04 Comparisons

Comparisons with EOP C04 Series

On the following pages, you will find a comparison between the individual solutions of the Analysis Centers and the IVS combination with respect to the C04 series. The C04 series provides Earth Orientation Parameters (EOP):

- Polar motion with respect to the crust
**X-Pole**and**Y-Pole**, - Irregularities of the rotation angle
**UT1-UTC**and**LOD**, - Celestial pole offsets
**dX**and**dY**

in reference to the precession-nutation model IAU2006 and with respect to the ITRF2008.

These values are smoothed at 1-day intervals and published by the IERS Earth Orientation Center. Since 1 December 2011, the EOP C04 series have been delivered with 30-day latency and include only final definitive values, as announced in IERS message 198. A description of the C04 series can be found at the C04-Guide.

For comparison, the missing X- and Y-Pole Rate of the C04 series are determined by a weighted linear interpolation of the X- and Y-Pole values, respectively.

The comparison is embedded in an interactive tool containing data of the last two year. The user is free to display the graphics of the individual solution, to choose the time-span and to overlay the residuals with their error bars.

The statistics table is updated according to the chosen data set(s). Tool tipping a data point provides a link to the analysis report of the corresponding session.