Crustal loading in vertical GPS time series in Fennoscandia

Maaria Nordman , Jaakko Mäkinen , Heikki Virtanen , Jan M. Johansson , Mirjam Bilker-Koivula , Jenni Virtanen

We compare time series of vertical position from GPS with modelled vertical deformation caused by variation in continental water storage, variation in the level of the Baltic Sea, and variation in atmospheric pressure. Monthly time series are used. The effect of continental water storage was calculated from three different global models. The effect of non-tidal variation in Baltic Sea level was calculated using tide gauge observations along the coasts. Atmospheric loading was computed from a numerical weather model. The loading time series are then compared with three different GPS time series at seven stations in Fennoscandia. A more detailed analysis is computed at three coastal stations. When the monthly GPS time series are corrected using the load models, their root-mean-square scatter shows an improvement between 40 and zero percent, depending on the site and on the GPS solution. The modelled load effect shows a markedly seasonal pattern of 15 mm peak-to-peak, of which the uncorrected GPS time series reproduce between 60 and zero percent.

Mots clés: Crustal loading; Baltic Sea; atmospheric pressure; continental water; GPS

Maaria Nordman, Jaakko Mäkinen, Heikki Virtanen, Jan M. Johansson, Mirjam Bilker-Koivula, et al.. Crustal loading in vertical GPS time series in Fennoscandia. Journal of Geodynamics, 2009, 48 (3-5), pp.144. ⟨10.1016/j.jog.2009.09.003⟩. ⟨hal-00594425⟩