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| Titel |
The evolution in the glacier mass balance of Hofsjökull ice cap, central Iceland, in 1986-2008, revealed by multi-source remote sensing data |
| VerfasserIn |
Eyjólfur Magnússon, Helgi Bjornsson, Helmut Rott, Sverrir Guðmundsson, Finnur Palsson, Etienne Berthier, Tomas Johannesson |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250042149
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| Zusammenfassung |
| We access how the net volume and area of Hofsjökull ice cap has evolved during the past
decades from various remote sensing data obtained in the summer 1986, the winter
1995-1996, summer 2004 and summer 2008. First, we use 5mx5m resolution DEM derived
from the airborne TopScan Lidar data obtained in 2008. Second, a DEM from 2004 derived
from SPOT5 optical images obtained during the SPIRIT project (20mx20m resolution).
Third, we use InSAR data from the ERS1/2 tandem mission to reconstruct a DEM for the
winter 1995-1996. Twenty InSAR scenes were topographically corrected with the existing
DEM’s. We developed a data fusion method to extract the topographic residual
signal in the interferograms and obtain a DEM corresponding to an average surface
elevation in the winter 1995-1996. Forth, we use a DEM derived by interpolating 20m
interval contours from a cartographic map based on aerial photographs in 1986. The
ice free areas of the high resolution TopScan DEM was used as a reference for
co-registering and vertical offset-correction of the DEM’s from 1986 and 2004.
The four data sets were also used to delineate the glacier margin at each time. The
glacier mass balance for the entire ice cap Hofsjökull, derived by subtraction of
DEM’s, was negative throughout our study period but declining from ~-0.3 m
yr-1 w. eq. in 1986-1995 to ~-1.1 m yr-1 w. eq. from 1995 onwards, while the
average summer temperature (at Hveravellir, central Iceland) increased from 4.6 Ë
C in the period 1987-1995 to 5.6 Ë C in the period 1996-2008. At the same time
the glacier has retreated from 918 km2 in 1986 to 849 km2 in 2008 or by 7.5%. |
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