TY - JOUR

T1 - Glacial isostatic adjustment in Fennoscandia from GRACE data and comparison with geodynamical models

AU - Steffen, Holger

AU - Denker, Heiner

AU - Müller, Jürgen

N1 - Funding information: We would like to thank the GRACE science team for the overall support, GFZ Potsdam, CSR, University of Texas, and JPL Pasadena for providing the GRACE monthly solutions, and Petra Döll and her group for making the WGHM data available. Many thanks also go to Kurt Lambeck for providing the RSES ice model and Georg Kaufmann for providing the modelling software ICEAGE (Kaufmann, 2004) . We would also like to thank Roland Schmidt, Andreas Güntner, Svetozar Petrovic (GFZ Potsdam), Sean Swenson (University of Colorado) and Wouter van der Wal (University of Calgary) for helpful discussions. We are very grateful for the excellent reviews and numerous valuable suggestions of Matthias Weigelt and an anonymous referee, which have greatly improved this manuscript. This research was funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) through research grant MU1141/8-1 (SPP 1257).

PY - 2008/3/25

Y1 - 2008/3/25

N2 - The Earth's gravity field observed by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. Several institutions, such as the GeoForschungsZentrum (GFZ) Potsdam, the University of Texas at Austin, Center for Space Research (CSR) and the Jet Propulsion Laboratory (JPL), Pasadena, provide GRACE monthly solutions, which differ slightly due to the application of different reduction models and centre-specific processing schemes. The GRACE data are used to investigate the mass variations in Fennoscandia, an area which is strongly influenced by glacial isostatic adjustment (GIA). Hence the focus is set on the computation of secular trends. Different filters (e.g. isotropic and non-isotropic filters) are discussed for the removal of high frequency noise to permit the extraction of the GIA signal. The resulting GRACE based mass variations are compared to global hydrology models (WGHM, LaDWorld) in order to (a) separate possible hydrological signals and (b) validate the hydrology models with regard to long period and secular components. In addition, a pattern matching algorithm is applied to localise the uplift centre, and finally the GRACE signal is compared with the results from a geodynamical modelling. The GRACE data clearly show temporal gravity variations in Fennoscandia. The secular variations are in good agreement with former studies and other independent data. The uplift centre is located over the Bothnian Bay, and the whole uplift area comprises the Scandinavian Peninsula and Finland. The secular variations derived from the GFZ, CSR and JPL monthly solutions differ up to 20%, which is not statistically significant, and the largest signal of about 1.2μ Gal/year is obtained from the GFZ solution. Besides the GIA signal, two peaks with positive trend values of about 0.8μ Gal/year exist in central eastern Europe, which are not GIA-induced, and also not explainable by the hydrology models. This may indicate that the recent global hydrology models have to be revised with respect to long period and secular components. Finally, the GRACE uplift signal is also in quite good agreement with the results from a simple geodynamical modelling.

AB - The Earth's gravity field observed by the Gravity Recovery and Climate Experiment (GRACE) satellite mission shows variations due to the integral effect of mass variations in the atmosphere, hydrosphere and geosphere. Several institutions, such as the GeoForschungsZentrum (GFZ) Potsdam, the University of Texas at Austin, Center for Space Research (CSR) and the Jet Propulsion Laboratory (JPL), Pasadena, provide GRACE monthly solutions, which differ slightly due to the application of different reduction models and centre-specific processing schemes. The GRACE data are used to investigate the mass variations in Fennoscandia, an area which is strongly influenced by glacial isostatic adjustment (GIA). Hence the focus is set on the computation of secular trends. Different filters (e.g. isotropic and non-isotropic filters) are discussed for the removal of high frequency noise to permit the extraction of the GIA signal. The resulting GRACE based mass variations are compared to global hydrology models (WGHM, LaDWorld) in order to (a) separate possible hydrological signals and (b) validate the hydrology models with regard to long period and secular components. In addition, a pattern matching algorithm is applied to localise the uplift centre, and finally the GRACE signal is compared with the results from a geodynamical modelling. The GRACE data clearly show temporal gravity variations in Fennoscandia. The secular variations are in good agreement with former studies and other independent data. The uplift centre is located over the Bothnian Bay, and the whole uplift area comprises the Scandinavian Peninsula and Finland. The secular variations derived from the GFZ, CSR and JPL monthly solutions differ up to 20%, which is not statistically significant, and the largest signal of about 1.2μ Gal/year is obtained from the GFZ solution. Besides the GIA signal, two peaks with positive trend values of about 0.8μ Gal/year exist in central eastern Europe, which are not GIA-induced, and also not explainable by the hydrology models. This may indicate that the recent global hydrology models have to be revised with respect to long period and secular components. Finally, the GRACE uplift signal is also in quite good agreement with the results from a simple geodynamical modelling.

KW - Filtering

KW - Geodynamic modelling

KW - Glacial isostatic adjustment

KW - Global hydrology models

KW - GRACE

KW - Pattern matching

UR - http://www.scopus.com/inward/record.url?scp=50549096887&partnerID=8YFLogxK

U2 - 10.1016/j.jog.2008.03.002

DO - 10.1016/j.jog.2008.03.002

M3 - Article

AN - SCOPUS:50549096887

VL - 46

SP - 155

EP - 164

JO - Journal of geodynamics

JF - Journal of geodynamics

SN - 0264-3707

IS - 3-5

ER -