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Abstract:
In recent years several sets of potential corrections to the current precession and nutation models IAU2006 and IAU2000 have been obtained by different teams, in whose derivation have participated a number of members of the IAU/IAG JWG on Improving theories and models of Earth rotation (ITMER). It was created to assist the development of the 2019 Resolution 5 of the IAG and has worked in close cooperation with IERS and GGOS through the participation in their 2019 and 2022 Unified Analysis Workshops, and also got an IAU high support with the approval of its 2021 Resolution B2.Regarding forced nutations, most sets of corrections are simply obtained by a refit of some lunisolar nutations. On the other hand, the sets derived by us include also corrections to the nutations of planetary origin. These corrections are far from being irrelevant, since their effect on the weighted root mean square of the celestial pole offsets series is comparable to that of the lunisolar terms.As for the free core nutation, most models follow the well-known sliding window approach that provides more insight into the underlying physics, although alternative approaches, like the multiband one, also may reduce the variance.The different teams have used various methodologies and basic input data. Our approach pays more attention to ordinary VLBI solutions, looking for minimizing the numerical effects that appear in the derivation of daily CPO series.This contribution presents a summary of the performance of those sets of potential corrections, including their behavior in VLBI data analysis.
