Vertical crustal motion observed in the BIFROST project

Scherneck, Hans‐Georg; Johansson, Jan M.; Koivula, Hannu; Dam, Tonie van; Davis, J. L.

doi:10.1016/s0264-3707(03)00005-x

Cited by 42 publications

(26 citation statements)

References 18 publications

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“…Theoretical estimates of the amplitude of the surface displacement using either a global convolution sum of surface pressure with an elastic Green's function (Farrell 1972) or a summation of the spherical harmonic representation of the pressure field with load Love numbers, indicates that the predicted surface displacement is often large enough to be detected by current geodetic techniques. In fact, the effects of atmospheric pressure loading have been detected in GPS coordinate time series (van Dam and Herring 1994;Dong et al 2002;Scherneck et al 2003;Zerbini et al 2004), VLBI coordinates (Rabbel and Schuh 1986;Manabe et al 1991;MacMillan and Gipson 1994;van Dam and Herring 1994;Petrov and Boy 2004) and SLR (Bock et al 2005). Atmospheric loading displacement values may be computed based on one of several computational methodologies and different input data sets, and at present these are held to be equally valid in most cases.…”

Section: Atmospheric Loading Displacementsmentioning

confidence: 99%

Improved Constraints on Models of Glacial Isostatic Adjustment: A Review of the Contribution of Ground-Based Geodetic Observations

et al. 2010

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The provision of accurate models of Glacial Isostatic Adjustment (GIA) is presently a priority need in climate studies, largely due to the potential of the Gravity Recovery and Climate Experiment (GRACE) data to be used to determine accurate and continent-wide assessments of ice mass change and hydrology. However, modelled GIA is 123Surv Geophys (2010) 31:465-507 DOI 10.1007/s10712-010-9100-4 uncertain due to insufficient constraints on our knowledge of past glacial changes and to large simplifications in the underlying Earth models. Consequently, we show differences between models that exceed several mm/year in terms of surface displacement for the two major ice sheets: Greenland and Antarctica. Geodetic measurements of surface displacement offer the potential for new constraints to be made on GIA models, especially when they are used to improve structural features of the Earth's interior as to allow for a more realistic reconstruction of the glaciation history. We present the distribution of presently available campaign and continuous geodetic measurements in Greenland and Antarctica and summarise surface velocities published to date, showing substantial disagreement between techniques and GIA models alike. We review the current state-of-the-art in ground-based geodesy (GPS, VLBI, DORIS, SLR) in determining accurate and precise surface velocities. In particular, we focus on known areas of need in GPS observation level models and the terrestrial reference frame in order to advance geodetic observation precision/accuracy toward 0.1 mm/year and therefore further constrain models of GIA and subsequent present-day ice mass change estimates.

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Section: Atmospheric Loading Displacementsmentioning

confidence: 99%

Improved Constraints on Models of Glacial Isostatic Adjustment: A Review of the Contribution of Ground-Based Geodetic Observations

et al. 2010

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“…In this respect, the project BIFROST (Baseline Inferences for Rebound Observations, Sea Level, and Tectonics) has been based on the GPS technique and geophysical modelling, and has delivered a maximum height change rate (with respect to a geocentric reference ellip-soid) of about 11 mm/year, cf. Milne et al (2001); Johansson et al (2002); Scherneck et al (2003); Lidberg et al (2007).…”

Section: The Fennoscandian Land Upliftmentioning

confidence: 99%

Observing Gravity Change in the Fennoscandian Uplift Area with the Hanover Absolute Gravimeter

Timmen

Gitlein

Klemann

et al. 2011

Pure Appl. Geophys.

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many Abbreviated title: Absolute Gravimetry in the Fennoscandian Uplift AreaThe Nordic countries Norway, Sweden, Finland and Denmark are a key study region for the research of glacial isostasy. In addition, it offers a unique opportunity for absolute gravimetry to show its capability as a geodetic tool for geophysical research. Within a multi-national cooperation, annual absolute gravity meas- The Fennoscandian Land UpliftIn the Fennoscandian land uplift area, the Earth's crust has been rising continuously since the last glacial maximum in response to the deloading of the ice. This process is an isostatic adjustment of the Earth's elastic lithosphere and underlying viscous mantle. For a general overview Wolf (1993) gives a historical review about the changing role of the lithosphere in models of glacial isostasy. The Fennoscandian rebound area is dominated by the Precambrian basement rocks of the BalticShield, which is part of the ancient East European Craton and comprises South Norway, Sweden, Finland, the Kola Peninsula and Russian Karelia. The region is surrounded by a flexural bulge, covering northern Germany and northern Poland, the Netherlands and some other surrounding regions.The bulge area was once rising due the Fennoscandian ice load and, after the melting, sinking with a much smaller absolute value than the uplift rate in the centre of Fennoscandia. Denmark is part of the transition zone from the uplift to the subsidence area. The maximum spatial extension of the uplift area is about 2000 km in northeast-southwest direction; see Figure 1 for the approximate shape (after Ågren and Svensson, 2007). Presently, the central area around the northern part of the Gulf of Bothnia is undergoing an uplift at a rate of about 1 cm/year. (Figure 1)Geophysical approaches to study the postglacial rebound are associated with the evidence for ancient shore lines and lake level data, the knowledge or assumptions about the geometry of the ice sheets (thickness, position), and some Earth model parameters (lithosphere thickness, mantle viscosity). After Lambeck et al. (1998b), the inverse solution for the sea level data includes both ice and Earth model parameters as unknowns. Despite the recent progress in understanding the underlying models, definite models for the isostatic rebound do not yet exist. Lateral rheological variations

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“…Time variable changes in the mass distribution of the atmosphere and continental water, load and displace the surface of the Earth to such an extent that they are observable in geodetic coordinate time series (van Dam and Herring 1994;van Dam et al , 1997van Dam et al , 2001Zerbini et al 2004;Schuh et al 2003;Scherneck et al 2002;Petrov and Boy 2004;Tesmer et al 2011;Lavallée et al 2010). Tidal and nontidal ocean mass changes also load the Earth's surface.…”

Section: Introductionmentioning

confidence: 99%

Nontidal ocean loading: amplitudes and potential effects in GPS height time series

Dam

Collilieux

Wuite

et al. 2012

J Geod

107

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Ocean bottom pressure (OBP) changes are caused by a redistribution of the ocean's internal mass that are driven by atmospheric circulation, a change in the mass entering or leaving the ocean, and/or a change in the integrated atmospheric mass over the ocean areas. The only previous global analysis investigating the magnitude of OBP surface displacements used older OBP data sets (van Dam et al. in J Geophys Res 129:507-517, 1997). Since then significant improvements in meteorological forcing models used to predict OBP have been made, augmented by observations from satellite altimetry and expendable bathythermograph profiles. Using more recent OBP estimates from the Estimating the Circulation and Climate of the Ocean (ECCO) project, we reassess the amplitude of the predicted effect of OBP on the height coordinate time series from a global distribution of GPS stations. OBP-predicted loading effects display an RMS scatter in the height of between 0.2 and 3.7 mm, larger than previously reported but still much smaller (by a factor of 2) than the scatter observed due to atmospheric pressure loading. Given the improvement in GPS hardware and data analysis techniques, the OBP signal is similar to the precision of weekly GPS height coordinates. We estimate the effect of OBP on GPS height coordinate time series using the MIT reprocessed solution, mi1. When we compare the predicted OBP height time series with mi1, we find that the scatter is reduced over all stations by 0.1 mm on average with reductions as high as 0.7 mm at some stations. More importantly we are able to reduce the scatter on 65 % of the stations investigated. The annual component of the OBP signal is responsible for 80 % of the reduction in scatter on average. We find that stations located close to semi-enclosed bays or seas are affected by OBP loading to a greater extent than other stations.

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Vertical crustal motion observed in the BIFROST project

Cited by 42 publications

References 18 publications

Improved Constraints on Models of Glacial Isostatic Adjustment: A Review of the Contribution of Ground-Based Geodetic Observations

Improved Constraints on Models of Glacial Isostatic Adjustment: A Review of the Contribution of Ground-Based Geodetic Observations

Observing Gravity Change in the Fennoscandian Uplift Area with the Hanover Absolute Gravimeter

Nontidal ocean loading: amplitudes and potential effects in GPS height time series

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