The impact of a No-Net-Rotation Condition on ITRF2000

[1] The realization of the International Terrestrial Reference System (ITRS) for 2000 (ITRF2000), provides an accurate estimation of relative motions for 6 major tectonic plates. In order to comply with the ITRS specification, a No-Net-Rotation Condition (NNRC) was applied by aligning the orientation time evolution of the ITRF2000 to that of the geophysical model NNR-NUVEL-1A. This implicit application of the NNRC, since the NNR-NUVEL-1A satisfies that condition, is achieved by using a consistent geodetic method, minimizing the global rotation rate betweenthe ITRF2000 and the NNR-NUVEL-1A model. The main focus of this paper is to examine how the ITRF2000 satisfies this condition by computing rotation rate components with respect to the Tisserand frame which is the basis of the NNRC. Numerical tests based on several approaches illustrate the sensitivity of the alignment to NNR-NUVEL-1A and they also show that the ITRF2000 is aligned at the 1 mm/yr level.