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- Nordman, M., et al.
(författare)
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Crustal loading in vertical GPS time series in Fennoscandia
- 2009
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Ingår i: J. Geodyn.. ; 48:3-5, s. 144-150
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Tidskriftsartikel (refereegranskat)abstract
- 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 0%, 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 0%.
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| 2. |
- Wickert, J, et al.
(författare)
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GNSS for Global Earth Observation: The European coordination action Gfg²
- 2012
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Ingår i: Sixth FORMOSAT-3/COSMIC Data Users' Workshop 30 October - 1 November 2012, Boulder, Colorado U.S.A..
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Konferensbidrag (övrigt vetenskapligt)abstract
- The Gfgsquared (GfG²) project is an international research related project with focus to the use of GNSS (Global Navigation Satellite Systems) for Earth Observation in a more general sense. Within the project novel GNSS applications with outstanding social importance are identified. These applications can be classified by the nine Social Benefit Areas (SBA), which address the current crucial problems of mankind: disasters, health, energy, climate, water, weather, ecosystems, agriculture, biodiversity (see www.earthobservation.org). We give examples for GNSS applications in the different SBA. For several of these applications, GNSS radio occultation is a key observation technique with several applications in that context.
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| 7. |
- Haugen, H. A., et al.
(författare)
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CCS in the Skagerrak/Kattegat area
- 2011
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Ingår i: Energy Procedia. 10th International Conference on Greenhouse Gas Control Technologies; Amsterdam; 19-23 September 2010. - 1876-6102. ; 4, s. 2324-2331
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Konferensbidrag (refereegranskat)
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| 8. |
- Milne, G.A., et al.
(författare)
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Continuous GPS measurements of postglacial adjustment in Fennoscandia: 2. Modeling results
- 2004
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Ingår i: Journal of Geophysical Research - Solid Earth. - 0148-0227. ; 109:B2
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Tidskriftsartikel (refereegranskat)abstract
- [1] Data collected under the auspices of the BIFROST GPS project yield a geographically dense suite of estimates of present-day, three-dimensional (3-D) crustal deformation rates in Fennoscandia [Johansson et al., 2002]. A preliminary forward analysis of these estimates [Milne et al., 2001] has indicated that models of ongoing glacial isostatic adjustment (GIA) in response to the final deglaciation event of the current ice age are able to provide an excellent fit to the observed 3-D velocity field. In this study we revisit our previous GIA analysis by considering a more extensive suite of forward calculations and by performing the first formal joint inversion of the BIFROST rate estimates. To establish insight into the physics of the GIA response in the region, we begin by decomposing a forward prediction into the three contributions associated with the ice, ocean, and rotational forcings. From this analysis we demonstrate that recent advances in postglacial sea level theory, in particular the inclusion of rotational effects and improvements in the treatment of the ocean load in the vicinity of an evolving continental margin, involve peak signals that are larger than the observational uncertainties in the BIFROST network. The forward analysis is completed by presenting predictions for a pair of Fennoscandian ice histories and an extensive suite of viscoelastic Earth models. The former indicates that the BIFROST data set provides a powerful discriminant of such histories. The latter yields bounds on the ( assumed constant) upper and lower mantle viscosity (nu(UM), nu(LM)); specifically, we derive a 95% confidence interval of 5 x 10(20) less than or equal to nu(UM) less than or equal to 10(21) Pa s and 5 x 10(21) less than or equal to nu(LM) less than or equal to 5 x 10(22) Pa s, with some preference for (elastic) lithospheric thickness in excess of 100 km. The main goal of the ( Bayesian) inverse analysis is to estimate the radial resolving power of the BIFROST GPS data as a function of depth in the mantle. Assuming a reasonably accurate ice history, we demonstrate that this resolving power varies from similar to 200 km near the base of the upper mantle to similar to 700 km in the top portion of the lower mantle. We conclude that the BIFROST data are able to resolve structure on radial length scale significantly smaller than a single upper mantle layer. However, these data provide little constraint on viscosity in the bottom half of the mantle. Finally, elements of both the forward and inverse analyses indicate that radial and horizontal velocity estimates provide distinct constraints on mantle viscosity.
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| 9. |
- Bergstrand, Sten, 1971-, et al.
(författare)
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BIFROST: Noise properties of GPS time series
- 2007
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Ingår i: in "Dynamic Planet: Monitoring and Understanding a Dynamic Planet with Geodetic and Oceanographic Tools", IAG Symposium, Cairns, Australia, 22-26 August, 2005, Series: International Association of Geodesy Symposia , Vol. 130, Tregoning, Paul; Rizos, Chris (Eds.), Springer. - 978-3-540-49349-5 ; 130, s. 123-130
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Konferensbidrag (refereegranskat)
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| 10. |
- Bergstrand, Sten, 1971-, et al.
(författare)
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Ionospheric Corrections for Accurate Positioning in Real Time
- 2005
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Ingår i: in Proc. Radio Science and Communication (RVK), eds. O. Gustafsson, P. Löwenborg, Linköping, Sweden, June 14-16, 2005. - 91-7056-122-2 ; s. 391-394
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Konferensbidrag (övrigt vetenskapligt)
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