The IfE absolute gravimetry plans for 2006, 2007, 2008,

and some additional considerations

Ludger Timmen, Olga Gitlein, Jürgen Müller, Heiner Denker

Contents:

• Our plans

• GW in Ålesund and Hannover

• Statistics of a station determination

• Remarks about station distribution and net improvements

Our plans (as applied to DFG)

“The Fennoscandian Land Uplift:a Test and Application Area for GRACE”

Absolute gravity determination with FG5-220 in Fennoscandia

in 2006: 15 stationsin 2007: 15 stationsin 2008: ~7 or 8 stations

(incl. reference and comparison measurements)

2008/2009: summing up and unifying of data sets (gravimetry and GPS height rates)

• joint IfE /(FGI, KMS/DNSC, LM, SK) gravimetry campaigns 2003 . . . 2008

• data exchange with partner institutes:• consideration of earlier campaigns (e.g. Wilmes et al. 2004) and recent campaigns with other absolute meters (UMB, BKG, FGI, NOAA)• BIFROST and latest GPS results

}Gravity field variations:gravity and geoid change caused by recent uplift in

Fennoscandia (surface point and area information, models)

11.09.04

18.02.05

24.08.0508.11.05

• reasonable record from the dipper: seasonal behaviour (low (!) water table in August),• assuming a porosity of 5% of Aksla: 3 m water table change may cause up to 5 μGal.

GW [m NN]: Gravimetry Lab Hannover

49.4

49.6

49.8

50

50.2

50.4

50.6

05

.12

.20

00

05

.02

.20

01

05

.04

.20

01

05

.06

.20

01

05

.08

.20

01

05

.10

.20

01

05

.12

.20

01

05

.02

.20

02

05

.04

.20

02

05

.06

.20

02

05

.08

.20

02

05

.10

.20

02

05

.12

.20

02

05

.02

.20

03

05

.04

.20

03

05

.06

.20

03

05

.08

.20

03

05

.10

.20

03

05

.12

.20

03

05

.02

.20

04

05

.04

.20

04

05

.06

.20

04

05

.08

.20

04

05

.10

.20

04

05

.12

.20

04

05

.02

.20

05

05

.04

.20

05

05

.06

.20

05

05

.08

.20

05

05

.10

.20

05

05

.12

.20

05

05

.02

.20

06

Absolute Gravity Determinations:r = 0.90, dg/dGW = 0.18 μGal/cm

BIFROST: Scherneck et al. 2003