HR: 1340h
AN: C23A-0975    [Abstracts]
TI: Velocity field of mountain glaciers measured by correlating SPOT5 images
AU: * Berthier, E
EM: etienne.berthier@cnes.fr
AF: LEGOS, 18 av. Ed. Belin, Toulouse, 31401 France
AU: Vadon, H
EM: helene.vadon@cnes.fr
AF: CNES, 18 av. Ed. Belin, Toulouse, 31401 France
AU: Baratoux, D
EM: david.baratoux@cnes.fr
AF: LDTP, 18 av. Ed. Belin, Toulouse, 31401 France
AU: Arnaud, Y
EM: yves.arnaud@ird.fr
AF: GREAT ICE (IRD), 54 Rue Moliere, BP 96, St Martin d'Heres, 38402 France
AU: Vincent, C
EM: vincent@lgge.obs.ujf-grenoble.fr
AF: LGGE, 54 Rue Moliere, BP 96, St Martin d'Heres, 38402 France
AU: Bjornsson, H
EM: hb@raunvis.hi.is
AF: RAUNVIS, Dunhaga 3, Reykjavik, IS-107 Iceland
AU: Palsonn, F
EM: fp@raunvis.hi.is
AF: RAUNVIS, Dunhaga 3, Reykjavik, IS-107 Iceland
AU: Feigl, K L
EM: feigl@pontos.cst.cnes.fr
AF: LDTP, 18 av. Ed. Belin, Toulouse, 31401 France
AU: Remy, F
EM: remy@pinot.legos.cnes.fr
AF: LEGOS, 18 av. Ed. Belin, Toulouse, 31401 France
AU: Legresy, B
EM: legresy@pinot.legos.cnes.fr
AF: LEGOS, 18 av. Ed. Belin, Toulouse, 31401 France
AB: A complete and detailed map of the velocity field on mountain glaciers is derived by cross-correlating SPOT5 optical images. This approach offers an alternative to SAR interferometry and speckle tracking, because no present or planned RADAR mission provides data with a temporal separation short enough to measure the displacements of mountain glaciers. A DEM and an accurate orbital model permit to project one of the SPOT5 images into the geometry of the other one before cross-correlation. The strong ablation occurring during summer time on glaciers requires a correction to obtain unbiased estimates of displacement. We assess the accuracy of our measurement by comparison with nearly simultaneous differential GPS surveys. If the images have similar incidence angles and correlate well, the accuracy is on the order of 0.5 m, or one fifth of the pixel size. Similar results are also obtained without ground control points and with the low resolution GTOPO30 DEM. Monitoring of remote glaciers is thus possible. On the studied glaciers (French Alps and Iceland), velocities are ranging from a few meters per year to over 500 m/year. The high accuracy and the large spatial coverage of our measurements allow monitoring the gglacial acceleration due to summertime surface melting. Our methodology, applied to SPOT5 images, can also be used to measure the deformation of the Earth's surface caused by landslides, earthquakes and volcanos.
DE: 1827 Glaciology (1863)
DE: 1640 Remote sensing
SC: Cryosphere [C]
MN: 2004 AGU Fall Meeting