HR: 17:00h
AN: G24A-05 INVITED     [Abstracts]
TI: Absolute Gravimetry in Fennoscandia - A Contribution to Understanding Postglacial Uplift
AU: * Pettersen, B R
EM: bjorn.pettersen@umb.no
AF: Institute fur Erdmessung, University of Hannover, Am Schneiderberg 50, Hannover, D-30167 Germany
AU: * Pettersen, B R
EM: bjorn.pettersen@umb.no
AF: Department of Mathematical Sciences and Technology, University of Environmental and Life Sciences, P O Box 5003, Aas, N-1432 Norway
AU: Timmen, L
G24A-05 AF: Institute fur Erdmessung, University of Hannover, Am Schneiderberg 50, Hannover, D-30167 Germany
AU: Gitlein, O
G24A-05 AF: Institute fur Erdmessung, University of Hannover, Am Schneiderberg 50, Hannover, D-30167 Germany
AU: Muller, J
G24A-05 AF: Institute fur Erdmessung, University of Hannover, Am Schneiderberg 50, Hannover, D-30167 Germany
AU: Denker, H
G24A-05 AF: Institute fur Erdmessung, University of Hannover, Am Schneiderberg 50, Hannover, D-30167 Germany
AU: Makinen, J
G24A-05 AF: Finnish Geodetic Institute, Geodeetinrinne 2, Masala, SF-02431 Finland
AU: Bilker, M
G24A-05 AF: Finnish Geodetic Institute, Geodeetinrinne 2, Masala, SF-02431 Finland
AU: Lysaker, D I
G24A-05 AF: Department of Mathematical Sciences and Technology, University of Environmental and Life Sciences, P O Box 5003, Aas, N-1432 Norway
AU: Omang, O C
G24A-05 AF: Department of Mathematical Sciences and Technology, University of Environmental and Life Sciences, P O Box 5003, Aas, N-1432 Norway
AU: Svendsen, J G
G24A-05 AF: Department of Mathematical Sciences and Technology, University of Environmental and Life Sciences, P O Box 5003, Aas, N-1432 Norway
AU: Wilmes, H
G24A-05 AF: Bundesamt fur Kartographie und Geodasie, Richard Strauss Allee 11, Frankfurt, D-60598 Germany
AU: Falk, R
G24A-05 AF: Bundesamt fur Kartographie und Geodasie, Richard Strauss Allee 11, Frankfurt, D-60598 Germany
AU: Reinhold, A
G24A-05 AF: Bundesamt fur Kartographie und Geodasie, Richard Strauss Allee 11, Frankfurt, D-60598 Germany
AU: Hoppe, W
G24A-05 AF: Bundesamt fur Kartographie und Geodasie, Richard Strauss Allee 11, Frankfurt, D-60598 Germany
AU: Scherneck, H
G24A-05 AF: Chalmers University of Technology, Onsala Space Observatory, Onsala, S-43992 Sweden
AU: Lidberg, M
G24A-05 AF: Chalmers University of Technology, Onsala Space Observatory, Onsala, S-43992 Sweden
AU: Engen, B
G24A-05 AF: Norwegian Mapping Authority, Kartverksveien 21, Honefoss, N-3511 Norway
AU: Kristiansen, O
G24A-05 AF: Norwegian Mapping Authority, Kartverksveien 21, Honefoss, N-3511 Norway
AU: Engfeldt, A
G24A-05 AF: National Land Survey of Sweden, Lantmaterigatan 2, Gavle, S-80182 Sweden
AU: Strykowski, G
G24A-05 AF: Danish National Space Center, Juliane Maries Vej 30, Copenhagen O, DK-2100 Denmark
AU: Forsberg, R
G24A-05 AF: Danish National Space Center, Juliane Maries Vej 30, Copenhagen O, DK-2100 Denmark
AU: Klopping, F
G24A-05 AF: National Geodetic Survey, 1315 East-West Highway, Silver Spring, MD 20910 United States
AU: Sasagawa, G
G24A-05 AF: Scripps Institution of Oceanography, 8602 La Jolla Shores Drive, La Jolla, CA 92037 United States
AB: The Fennoscandian postglacial uplift has been mapped geometrically using precise levelling, tide gauges, and networks of permanent GPS stations. The results identify major uplift rates at sites located around the northern part of the Gulf of Bothnia. The vertical motions decay in all directions away from this central location. An oval shaped zero uplift isoline tracks the general western and northern coastline of Norway and the Kola peninsula. It returns southwest through Russian Karelia and touches the southern tip of Sweden and northern Denmark. The uplift area (as measured by present day motions) has its major axis in the direction of southwest to northeast and covers a distance of about 2000 km. Absolute gravimetry was made in Finland and Norway in 1976 with a rise-and fall instrument. A decade later the number of gravity stations was expanded by JILAg-5, in Finland from 1988, in Norway from 1991, and in Sweden from 1992. FG5 was introduced in these three countries in 1993 (7 stations) and continued with an extended campaign in 1995 (12 stations). In 2003 a project was initiated by IfE, Hannover to collect observations simultaneously with GRACE on an annual cycle. New instruments were acquired by IfE (FG5-220), FGI (FG5-221), and UMB (FG5-226). New absolute gravity stations were established by the national mapping agencies in Denmark, Norway, and Sweden. The total number of prepared sites in Fennoscandia is now about 30. Most of them are co-located with permanent GPS, for many of which time series of several years are now available. Along the coast there are nearby tide gauge stations, many of which have time series of several decades. We describe the observing network, procedures, auxiliary observations, and discuss results obtained for selected sites. We compare the gravity results from different instruments and discuss the challenges of combining and validating such data products. Examples are shown where temporal gravity change may be compared to geometrical movements. Various effects, both instrumental and environmental, are affecting the observed results. Some require better understanding and improved modelling. We outline the future expectations of the Fennoscandian absolute gravity project, also in relation to preliminary results from GRACE.
DE: 1200 GEODESY AND GRAVITY
DE: 1211 Non-tectonic deformation
DE: 1217 Time variable gravity (7223, 7230)
DE: 1240 Satellite geodesy: results (6929, 7215, 7230, 7240)
SC: Geodesy [G]
MN: Fall Meeting 2005