Geodetic reference frames in the presence of crustal deformations - with focus on Nordic conditions

摘要

We investigate the agreement between the official national realisations of the European reference frame ETRS89 in the Nordic and Baltic area, using a Nordic GPS campaign from the autumn 2003. In this study we focus on the implementation and use of a model for deformations due to the Fennoscandian Glacial Isostatic Adjustment (GIA) process. The national realisations of ETRS89 are performed at different time epochs and no corrections for intraplate deformations have been applied. The national ETRS89 realisations therefore relate to the shape of the earth at different epochs in time between the autumn of 1994 and mid 1999, which for the Nordic area imply a deformation at the 10 cm level in the vertical if compared to the stated epoch 1989.0 for ETRS89. In order to facilitate the common use of ETRS89 within the European Community it is necessary to maintain ETRS89 as an accurate pan-European high quality geodetic reference frame. This prompts for a clarification regarding the epoch for internal deformation in future ETRS89 realisations.