The Cryosphere Discuss., 4, 2415-2432, 2010
www.the-cryosphere-discuss.net/4/2415/2010/
doi:10.5194/tcd-4-2415-2010
© Author(s) 2010. This work is distributed
under the Creative Commons Attribution 3.0 License.
Review Status
This discussion paper has been under review for the journal The Cryosphere (TC). A final paper in TC is not foreseen.
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

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 enhanced melting.


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.
 
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