Analysis of Pole Coordinate Data Predictions in the Earth Orientation Parameters Combination of Prediction Pilot Project

In October 2010 the US Naval Observatory together with the Space Research Centre in Warsaw initiated the Earth Orientation Parameters Combination of Prediction Pilot Project, which was accepted by the IERS Directing Board. The goal of this project is to determine the feasibility of combining Earth Orientation Parameters (EOP) predictions on an operational basis. The ensemble predictions of EOPs are more accurate than the results from individual predictions. The pole coordinate data predictions from different prediction contributors and ensemble predictions computed by the U.S. Naval Observatory are studied to determine the statistical properties of polar motion forecasts by looking at second, third and fourth moments about the mean. The increase of prediction errors in pole coordinate data can be due to the change of phase of the annual oscillation in the joint atmospheric-ocean excitation function.