Terrestrial geodetic measurements in West Greenland for investigating ice mass changes and for establishing ground control for remote sensing
Abstract- Since 1991, terrestrial geodetic measurements on the Greenland ice sheet are performed in order to determine height change, ice flow velocity and deformation (strain) in a test field around the Swiss-Camp near equilibrium line (1150 m a.s.l.). A new test field (ST2) in lower altitude (1000...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.141.4682 http://www.isprs.org/publications/related/ISRSE/html/papers/887.pdf |
| Summary: | Abstract- Since 1991, terrestrial geodetic measurements on the Greenland ice sheet are performed in order to determine height change, ice flow velocity and deformation (strain) in a test field around the Swiss-Camp near equilibrium line (1150 m a.s.l.). A new test field (ST2) in lower altitude (1000 m) was established in 2004. The stakes in the test fields are measured by static GPS and topographical survey by kinematic GPS on an area of about 2x2 km 2 each. Digital elevation models are derived in every epoch, so elevation changes and volume changes between different epochs could be calculated. At the Swiss-Camp the horizontal flow vector between 1991 and 2004 gives a velocity of 0,317 m/d and azimuth of 260,24 gon, so towards Jakobshavn Isbrae. Between 1991 and 2002 the long periodic elevation change is –0,22 m/a, but-0,85 m/a most recently between 2002 – 2004, indicating an acceleration of ice mass decreasing. All the terrestrial measurements can also be used as control areas for calibration and validation of remote sensing methods, such as ICESat (USA), CryoSat (ESA/Europe) or ERS1/2 (Europe) and some laser altimetry surveys by airplanes (USA, Denmark). The research areas “Swiss Camp” and “ST2 ” are small, but elevation, elevation change and flow velocity are precisely determined over many years, and so recommended as control areas. |
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