Journal Article

Prospects of Predicting the Polar Motion Based on the Results of the Second Earth Orientation Parameters Prediction Comparison Campaign

Gou, Junyang, Guessoum, Sonia, Nastula, Jolanta, Boggs, Dale, Thomas, Maik, Zhou, Zhijin, Dhar, Sujata, Irrgang, Christopher, Miao, Wei, Liu, Lintao, Raut, Shrishail, Kur, Tomasz, Soja, Benedikt, Ligas, Marcin, Wińska, Malgorzata, Mayer, Volker, Kudrys, Jacek, Zhao, Xin, Duan, PengShuo, Schuh, Harald, Bizouard, Christian, Ratcliff, Todd, Gross, Richard, Bruni, Sara, Otten, Michiel, Heinkelmann, Robert, Su, Xiaoqing, Chin, Mike, Shahvandi, M. Kiani, Michalczak, Maciej, Wu, Yuanwei, Xu, CanCan, Ferrandiz, Jose M., Thaller, Daniela, Chen, Lue, Saynisch‐Wagner, Jan, Belda, Santiago, Schoenemann, Erik, Śliwińska‐Bronowicz, Justyna, Lu, Weitao, Modiri, Sadegh, Schartner, Matthias, Han, Songtao, Yang, Xinyu, Wang, Guocheng, Xu, Xueqing, Dobslaw, Henryk, Dill, Robert, Li, Jia, Huang, ChengLi, Partyka, Aleksander

2024

Overview

Growing interest in Earth Orientation Parameters (EOP) resulted in various approaches to the EOP prediction algorithms, as well as in the exploitation of distinct input data, including the observed EOP values from various operational data centers and modeled effective angular momentum functions. Considering these developments and recently emerged new methodologies, the Second Earth Orientation Parameters Prediction Comparison Campaign (2nd EOP PCC) was pursued in 2021–2022. The campaign was led by Centrum Badań Kosmicznych Polskiej Akademii Nauk in cooperation with Deutsches GeoForschungsZentrum and under the auspices of the International Earth Rotation and Reference Systems Service. This paper provides the analysis and evaluation of the polar motion predictions submitted during the 2nd EOP PCC with the prediction horizons between 10 and 30 days. Our analysis shows that predictions are highly reliable with only a few occasional discrepancies identified in the submitted files. We demonstrate the accuracy of EOP predictions by (a) calculating the mean absolute error relative to polar motion observations from September 2021 through December 2022 and (b) assessing the stability of the predictions in time. The analysis shows unequal results for the x and y components of polar motion (PMx and PMy, respectively). Predictions of PMy are usually more accurate and have a smaller spread across all submitted files when compared to PMx. We present an analysis of similarity between the participants to indicate what methods and input data give comparable output. We also prepared the ranking of prediction methods for polar motion summarizing the achievements of the campaign. Plain Language Summary Polar motion consists of two time‐variable angles that characterize the orientation of the Earth's rotational axis with respect to a terrestrial reference frame attached to the surface of the solid Earth. It can be measured by space geodetic techniques, like Global Navigation Satellite Systems or Very Long Baseline Interferometry (VLBI). However, the final VLBI solutions used by geodetic processing centers to provide the values of polar motion have a latency of around 1 month. Therefore, predicted values are necessary for operational applications such as spacecraft navigation. To assess current methods of predicting polar motion time series, the Second EOP Prediction Comparison Campaign was pursued under the auspices of the International Earth Rotation and Reference Systems Service. The campaign aimed to test current achievements in polar motion predictions obtained with a variety of computational methods (including least squares, machine learning, and a Kalman filter) under realistic conditions. By evaluating the results of the campaign, we show that some of the prediction methods utilized do indeed reduce prediction errors and enhance prediction accuracy by using geophysical information from the fluid Earth's layers: Atmosphere, oceans, and terrestrial hydrosphere. Key Points Polar motion predictions for the y component are more accurate than for the x component Least squares and auto regression with effective angular momentum data provides the best results for polar motion prediction Some of the submitted predictions show higher accuracy than the IERS solution

• Publisher: John Wiley & Sons, Inc,American Geophysical Union (AGU)
• Subject: Accuracy / Earth orientation parameters / Earth orientation parameters prediction comparison campaign / Earth rotation / effective angular momentum / Forecasting / Kalman filters / Measurement techniques / Observatories / polar motion / predictions