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Combination of geodetic observations and models for glacial isostatic adjustment fields in Fennoscandia

Hill, Emma M.; Davis, James L.; Tamisiea, Mark E.; Lidberg, Martin. 2010 Combination of geodetic observations and models for glacial isostatic adjustment fields in Fennoscandia. Journal of Geophysical Research, 115, B07403. 12, pp. 10.1029/2009jb006967

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Abstract/Summary

We demonstrate a new technique for using geodetic data to update a priori predictions for Glacial Isostatic Adjustment (GIA) in the Fennoscandia region. Global Positioning System (GPS), tide gauge, and Gravity Recovery and Climate Experiment (GRACE) gravity rates are assimilated into our model. The technique allows us to investigate the individual contributions from these data sets to the output GIA model in a self-consistent manner. Another benefit of the technique is that we are able to estimate uncertainties for the output model. These are reduced with each data set assimilated. Any uncertainties in the GPS reference frame are absorbed by reference frame adjustments that are estimated as part of the assimilation. Our updated model shows a spatial pattern and magnitude of peak uplift that is consistent with previous models, but our location of peak uplift is slightly to the east of many of these. We also simultaneously estimate a spatially averaged rate of local sea level rise. This regional rate (similar to 1.5 mm/yr) is consistent for all solutions, regardless of which data sets are assimilated or the magnitude of a priori GPS reference frame constraints. However, this is only the case if a uniform regional gravity rate, probably representing errors in, or unmodeled contributions to, the low-degree harmonic terms from GRACE, is also estimated for the assimilated GRACE data. Our estimated sea level rate is consistent with estimates obtained using a more traditional approach of direct "correction" using collocated GPS and tide gauge sites

Item Type: Publication - Article
Digital Object Identifier (DOI): 10.1029/2009jb006967
Programmes: Oceans 2025 > Climate, ocean circulation and sea level
ISSN: 0148-0227
Additional Information. Not used in RCUK Gateway to Research.: Hill, Emma M. Davis, James L. Tamisiea, Mark E. Lidberg, Martin NASA [NNX08AJ79G, NNX07AM77G]; Natural Environment Research Council This work was supported by NASA grants NNX08AJ79G and NNX07AM77G (EMH and JLD), and by the Natural Environment Research Council's Oceans 2025 program (MET). We thank R. Hass for useful discussions regarding least squares collocation, and are grateful to K. Fleming and R. Sabadini for their insightful reviews. This work also benefitted from discussions with members of the Stable North America Reference Frame (SNARF) Working Group. Some figures were generated using the Generic Mapping Tools [Wessel and Smith, 1998]. Amer geophysical union Washington
Additional Keywords: POST GLACIAL SEA LEVEL; ICE AGE EARTH; FORMULATION EQUATION; RECORDS; SURFACE; GRACE; MODELLING
NORA Subject Terms: Marine Sciences
Date made live: 07 Apr 2011 15:19
URI: http://nora.nerc.ac.uk/id/eprint/13776

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