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| Titel |
Gravity changes in mid-west Greenland from GOCE gravity model and gradient data using ground and airborne gravity. |
| VerfasserIn |
Carl Christian Tscherning, Matija Herceg |
| Konferenz |
EGU General Assembly 2014
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 16 (2014) |
| Datensatznummer |
250087699
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| Publikation (Nr.) |
 EGU/EGU2014-1759.pdf |
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| Zusammenfassung |
| GOCE (ESA’s Gravity and Ocean Circulation Explorer) TRF (terrestrial reference frame)
vertical anomalous gradients (Tzz) from the periods winter 2009 and summer 2012 have
been used to determine gravity anomalies in mid-west Greenland, where a large
mass-loss has been detected using GRACE. As additional data were used the GOCE
DIR-3 model and ground gravity at the coast on solid rock, where no mass loss is
expected.
The methods of Least-Squares Collocation (LSC) and the Reduced Point Mass (RPM)
methods have been used, however only LSC included the ground data. The latter method also
permits the computation of error-estimates, which range from 3 mgal at the coast to 19 mgal
75 km from the coast in Eastern direction towards the ice-cap. The gravity anomaly
differences vary from -30 mgal to 30 mgal. It is negative (showing mass loss) around
the Jacobshavn Isbrae (latitude 69o15’, longitude 49o W-50oW, where the yearly
mass-loss has been estimated to correspond to -2 mgal, i.e. about -7 mgal for the
period considered. The computed change range from 0 to -10 mgal in the area, with
the error estimated to increase from 4 mgal to 15 mgal from West to East. This
shows the capability of using GOCE Tzz and ground gravity to determine mass
changes.
The GOCE DIR-3 model was also used to evaluate gravity values in the points of the
Greenland airborne gravity survey performed in 1991 and 1992. The differences had a mean
value of 0.9 and a standard deviation of 17.3 mgal for all of Greenland. In the South-West
area the mean of the differences was 0.15 and the standard deviation 7.14. This
indicate that possibly no total mass loss has occurred in Greenland from 1992 to 2012. |
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