[1] Effective angular momentum functions from atmosphere, oceans, and terrestrial water storage are obtained from European Centre for Medium-Range Weather Forecasts atmospheric data and corresponding simulations with the Ocean Model for Circulation and Tides and the Land Surface and Discharge Model (LSDM). Mass exchanges among the subsystems are realized by means of freshwater fluxes, causing the total ocean mass to vary predominantly annually. Variations in total ocean mass affect the oceanic excitations of the annual wobble by almost 1 milliarc second (mas) for both prograde and retrograde components, whereas the motion term contributions of terrestrial water flow derived from LSDM are found to be 3 orders of magnitude smaller. Since differences to geodetic excitations are not substantially reduced and regional decompositions demonstrate the large spatial variability of contributions to seasonal polar motion excitation that compensate each other when integrated globally, it is concluded that the closure of the seasonal excitation budget is still inhibited by remaining model errors in all subsystems.Citation: Dobslaw, H., R. Dill, A. Grötzsch, A. Brzeziński, and M. Thomas (2010), Seasonal polar motion excitation from numerical models of atmosphere, ocean, and continental hydrosphere,

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Seasonal excitation of polar motion estimated from recent geophysical models and observations. Journal of Geodynamics, Elsevier, 2009, 48 (3-5) This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.Page 1 of 8A c c e p t e d M a n u s c r i p t AbstractHere we investigate the seasonal excitation balance of polar motion using recent geophysical data sets and models. Attention is focused on the contribution of the land hydrology which is expressed either by models, such as CPC, GLDAS, LaD, or by the observations provided by the experiment GRACE. Geophysical excitation series are compared to each other and to the excitation inferred from the space geodetic observations of polar motion. Comparison shows that 3 models of land hydrology considered in this work differ considerably; adding the corresponding excitation series to the combination of atmospheric and oceanic excitation data does not clearly improve agreement with observations. But combination of the GRACE-derived mass term of excitation with the motion terms of atmospheric and oceanic excitations brings the excitation balance considerably closer in case of the retrograde/prograde annual and retrograde semiannual components of polar motion. For other seasonal components as well as for the nonharmonic residuals, the estimated contributions of hydrology do not improve the excitation balance of polar motion.