Benefits of refined 10-day effective angular momentum forecasts for earth rotation parameter prediction
Year: 2025
Type: article
Abstract: Effective angular momentum (EAM) forecasts are widely used as an important input for predicting both polar motion and dUT1. So far, model predictions for atmosphere, ocean, and terrestrial hydrosphere utilized in Earth rotation research reach only 6-days into the future. GFZ’s oceanic and land-surface model forecasts are forced with operational 6-day high-resolution deterministic numerical weather predictions provided by the European Centre for Medium-range Weather Forecasts. Those atmospheric forecasts extend also further into the future with a reduced sampling rate of just 6 h but the prediction skill decreases rapidly after roughly one week. To decide about publishing 10-day instead of 6-day model-based EAM forecasts, we generated a test set of 454 individual 10-day forecasts and used it with GFZ’s EAM Predictor method to calculate Earth rotation predictions. Using 10-day instead of 6-day EAM forecasts leads to slight improvements in y-pole and dUT1 predictions for 10 to 30 days ahead. By introducing additional neural network models trained on the errors of the EAM forecasts when compared to their subsequently available analysis runs, Earth rotation prediction can be enhanced even further. A reduction of the mean absolute errors for polar motion and length-of-day prediction at a forecast horizon of 10 days of 26.8% in x-pole, 15.5% in y-pole, 27.6% in dUT1, and 47.1% in $$\Delta $$ Δ LOD is achieved. This test application successfully demonstrates the potential of the extended EAM forecasts for Earth rotation prediction although the success rate has to be further improved to arrive at robust routine predictions. GFZ publishes from October 2024 onwards raw uncorrected 10-day instead of 6-day EAM forecasts at www.gfz-potsdam.de/en/esmdata for the individual contributions of atmosphere, ocean, and terrestrial hydrosphere. Users interested in the summarized effect of all subsystems are advised to use the 90-day combined EAM forecast product that also makes use of the presented corrections to the EAM forecasts.
Source: Journal of Geodesy
Authors: R. Dill, L. Stumpe, J. Saynisch-Wagner, M. Thomas, H. Dobslaw
Institution: GFZ Helmholtz Centre for Geosciences
Language: English
Subfield: Oceanography
Field: Earth and Planetary Sciences
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,590
Funder: Deutsche Forschungsgemeinschaft
Awards: Vorhersageverbesserung von Erdorientierungsparametern für die Echtzeitgeodesie, Zurückliegende und zukünftige hochgenaue und konsistente Erdorientierungsparameter für die Geodätische Forschung im Rahmen der Erdsystemwissenschaften (PROGRESS), Entschlüsselung klimatischer Signale in geodätisch beobachteten Erdorientierungsparametern
OpenAlex ID: W4407545738