# 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 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 statistics table is updated according to the chosen data set(s).