dot
Detailansicht
Katalogkarte GBA
Katalogkarte ISBD
Suche präzisieren
Drucken
Download RIS
Hier klicken, um den Treffer aus der Auswahl zu entfernen
Titel Reduced glacier sliding caused by persistent drainage from a subglacial lake
VerfasserIn E. Magnusson, H. Björnsson, H. Rott, F. Pálsson
Medientyp Artikel
Sprache Englisch
ISSN 1994-0416
Digitales Dokument URL
Erschienen In: The Cryosphere ; 4, no. 1 ; Nr. 4, no. 1 (2010-01-15), S.13-20
Datensatznummer 250001542
Publikation (Nr.) Volltext-Dokument vorhandencopernicus.org/tc-4-13-2010.pdf
 
Zusammenfassung
We present velocity observations of a glacier outlet in Vatnajökull, Iceland, deduced from interferometric SAR (InSAR) data obtained during the ERS1/2 tandem mission in 1995–2000. More than a 50% decrease in glacier velocity was observed subsequent to a large jökulhlaup from the subglacial lake Grímsvötn in 1996. The glacier had not reached its former flow rate in 2000. The jökulhlaup damaged the lake's ice-dam causing persistent drainage from the lake. InSAR based studies of water accumulation within Grímsvötn suggest that a leakage of >3 m3 s−1 prevailed throughout our study period. We suggest that the lake leakage kept open a tunnel at low water pressure underneath the whole length of the glacier. The tunnel flow drained water from its surroundings, hence lowering the water pressure of a distributed drainage system, underneath the upper and centre parts of the glacier, which prior to the jökulhlaup sustained significant basal sliding. This is in accordance with theoretical prediction that tunnel flow in a steady state may cause slow-down in glacier velocity by reducing the subglacial water pressure. The width of the affected areas was ~5 km on the upper part of the glacier and ~8 km on the centre part of the glacier. This indicates that the water pressure reduction propagates laterally from the tunnel over a distance of a few km.
 
Teil von