# Comparisons with EOP C04 Series

On the following pages you will find a comparison between the individual solutions of the analysis centres 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**

referred 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 Centre. Since 1^{th} December 2011, the EOP C04 series is delivered with 30-day latency and includes only final definitive values, cf. 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 into an interactive tool containing data since 1983. The values are smoothed by a moving median. The subset size of the sliding window is ±35 days and is shifted forward each 7 days. The user is free to display the graphics of the individual solution and to choose the time-spans.

The statistic table is updated according to the chosen data set(s).