[G04-1] Earth rotation and geodynamics I

[G04-1-02] Short-term Angular Momentum Forecasts for Polar Motion Prediction

^○Maik Thomas¹, Robert Dill¹, Henryk Dobslaw¹, Christian Bizouard² (1.GFZ German Research Centre for Geosciences, Potsdam, Germany, 2.Observatoire de Paris, Paris, France)

The Earth System Modelling group at GeoForschungsZentrum (GFZ) Potsdam provides operational 6-day forecasts of Earth rotation excitation due to atmospheric, oceanic, and hydrologic angular momentum changes. These EAM forecasts extend the 40 years long EAM series for 6 days into the future with a temporal resolution of 3 hours for both AAM and OAM. A set of 6-day EAM hindcasts from 2016 to 2017 for Earth rotation forecasts reveals positive prediction skills for up to 8 days into the future. Compared to the IERS predictions of bulletin A, the introduction of the 6-day EAM forecasts improves the prediction for more than 10 days into the future for both polar motion and length of day variations. Thus, not only the AAM forecasts as currently used for UT1 predictions in bulletin A, but also OAM forecasts and to a smaller extent HAM forecasts improve polar motion prediction, in particular for lead-times between 2 and 8 days. We will also report about early results obtained at Observatoire de Paris to predict polar motion from the integration of GFZ's 6-day EAM forecasts into the Liouville equation in a routine setting that fully takes into account the operational latencies of all required input products.