Single Abstract Details
| id : | 77 |
| titel : | Constraining No-Net Rotation of the Terrestrial Reference Frame |
| authors : | C. Kreemer, D. Lavallée, G. Blewitt, and W.E. Holt |
| abstract : | The time evolution of the ITRF orientation is currently defined by the no-net-rotation (NNR) condition as given by NNR-NUVEL1A. The NNR-NUVEL1A model is however at places inconsistent with the actual ITRF station velocities, because 1) NUVEL1A has known model deficiencies, 2) NUVEL1A does not account for plate boundary zones and 3) geodetic estimates of some plate’s motions differs from NUVEL-1A. This inconsistency becomes apparent when ITRF2000/2005 is compared to our NNR model (GSRM-NNR-2) that is based on our best knowledge of the Earth’s current horizontal surface velocity field. That is, a considerable rotation exists between GSRM-NNR-2 and ITRF2000/2005, which can yield up to a maximum of 3 mm/yr velocity difference. As we have shown elsewhere [Kreemer et al., 2006], the GSRM-NNR-2 is very robust to certain data/model assumptions, with the exception of a case when 1) we use a station velocity solution that is very limited in spatial coverage (as opposed to the ~5700 velocities currently used in GSRM-NNR-2), and 2) we consider a considerable origin translation rate bias in the ITRF station velocity solution. We explore here further the impact of a translation rate on our NNR model given translation rates based on a variety of geophysical constraints such as post-glacial rebound. More generally, we explore the perturbation of our NNR model as function of the direction of a hypothetical bias in translation rate. |
| correspondent : | Corné Kreemer |
| email : | kreemer@unr.edu |