Frank Lemoine (NASA / GSFC, USA); Brian Beckley (SGT / GSFC, USA); Doug Chinn (SGT / GSFC, USA); Despina Pavlis (SGT / GSFC, USA); Jean-Paul Boy (EOST/IPGS (UMR 7516 CNRS – Université de Strasbourg), France); Pierre Exertier (UMR Geoazur, Universit´e de Nice, Observatoire de la Cˆote d’Azur, France)

The mass redistribution of continental water, oceans, and atmosphere at the Earth’s surface cause seasonal geocenter variations with amplitudes of a few mm. Continental water is believed to be the largest contributor to geocenter motion as compared to the atmosphere and the oceans (Wu et al. 2012). However it is possible the phases and amplitudes of the seasonal geocenter contributions from these different sources will differ over time. Furthermore, the true geocenter is better represented with improved modeling of the center of figure which includes non-tidal surface deformation (Wu et al., 2012). The more accurate representation of the geocenter motion in altimeter satellite POD will ensure that orbit centering more truly reflects the Earth’s center of mass, and consequently better references the altimeter sea surface to the Earth’s center of mass (CM). Using 24-years (1993-2016) of LAGEOS 1-2 Satellite Laser Ranging (SLR) data we evaluate new ITRF2014-based models of geocenter motion for application to altimeter satellite orbit determination, where we test forward modeling of the station displacement corrections due to atmospheric loading. The derived geocenter annual models are compared to other estimates. Orbit centering is evaluated with TOPEX/Jason SLR/DORIS ITRF2014-based and JTRF2014-based POD.