Re-computation of the BIFROST GPS network and study of possible periodic effects

摘要

GPS data from the Nordic permanent GPS networks and other continuously operating GPS stations in northern Europe are analysed on a daily basis within the BIFROST (Baseline Inferences for Fennoscandian Rebound Observations, Sea level, and Tectonics) effort. these daily computations are performed in the same way today as initially set up in 1993. the purpose is to maintain a consistent data set of daily solutions. To increase the reliability in the position time series of the BIFROST GPS stations,d the re-computation of the complete data set from the BIFROST network is currently our main effort. Hereby we use various computation strategies, e.g. the PPP (Precise Point Positioning) strategy, developed in the mid-nineties. From other studies performed in the Finnish Permanent GPS network, FinnRef, annual and diurnal periods in vector components between stations have been reported. Recently similar periodicities have also been reported to occur in a global mode of earth deformation, detectable by GPS and VLBI, and caused by redistribution of masses between the Northern and the Southern Hemisphere. This paper will give a first overview of the re-computation of the BIEFOST network,d and an investigation of possible periodic signals in the GPS stations position time series using the last 5 years of data.