Photogrammetric determination of spatio-temporal velocity fields at Glaciar San Rafael in the Northern Patagonian Icefield H.-G. Maas1, G. Casassa2, D. Schneider1, E. Schwalbe1, and A. Wendt2 1Institute of Photogrammetry and Remote Sensing, Dresden University of Technology, Dresden, Germany 2Centro de Estudios Científicos, Valdivia, Chile
Received: 24 August 2010 – Accepted: 04 October 2010 – Published: 12 November 2010
Abstract. Glaciar San Rafael in the Northern Patagonian Icefield, with a length of 46 km and
an ice area of 722 km2, is the lowest latitude tidewater outlet
glacier in the world and one of the fastest and most productive glaciers in
southern South America in terms of iceberg flux. In a joint project of the
TU Dresden and CECS, spatio-temporal velocity fields in the region of the
glacier front were determined in a campaign in austral spring of 2009.
Monoscopic terrestrial image sequences were recorded with an intervallometer
mode high resolution digital camera over several days. In these image
sequences, a large number of glacier surface points were tracked by subpixel
accuracy feature tracking techniques. Scaling and georeferencing of the
trajectories obtained from image space tracking was performed via a
multi-station GPS-supported photogrammetric network.
The technique allows for tracking hundreds of glacier surface points at a
measurement accuracy in the order of one decimeter and an almost arbitrarily
high temporary resolution. The results show velocities of up to 16 m per
day. No significant tidal signals could be observed. Our velocities are in
agreement with earlier measurements from theodolite and satellite
interferometry performed in 1986–1994, suggesting that the current thinning
of 3.5 m/y at the front is not due to dynamic thinning but rather by
Citation: Maas, H.-G., Casassa, G., Schneider, D., Schwalbe, E., and Wendt, A.: Photogrammetric determination of spatio-temporal velocity fields at Glaciar San Rafael in the Northern Patagonian Icefield, The Cryosphere Discuss., 4, 2415-2432, doi:10.5194/tcd-4-2415-2010, 2010.