Glacier Mass Balance Changes and Meltwater Discharge (selected papers from sessions at the IAHS Assembly in Foz do Iguaçu

• Main Authors: Rodrigo Zamora, Gino Casassa, Andres Rivera, Fernando Ordenes, Guillermo Neira, Luis Araya, Ronald Mella, Claudio Bunster
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: East Antarctica; Antarc*; Antarctica
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.1085.4041; http://www.glaciologia.cl/web/glaciologia_es/glaciologiacms/upload/zamora2007.pdf

Abstract Detection of crevasses is critical for safe travelling on glaciers. Here we present the use of a Ground Penetrating Radar (GPR) for crevasse detection. Experiments were made in temperate ice on Glaciar Mocho, Volcán MochoChoshuenco, southern Chile (39°25′S) and in cold ice in East Antarctica (87°30′S). In southern Chile the radar was hand-carried 1.2 m in front of the operator who was walking over the glacier at a speed of ~0.5 m s -1 , while in Antarctica it was mounted on a 7 m-long rod in front of a tractor convoy travelling at a speed of ~2 m s -1 . In both geographical sites profiles were made perpendicularly to crevasses ranging in width from 0.1 m to 1.0 m. Buried crevasses clearly show as apexes of diffraction hyperbolae, which could be detected down to a depth of 15 m. Show as discontinuities in the firn stratigraphy which have a width equal to the crevasse width, and associated diffraction hyperbolae to each side of the crevasse. The GPR proved to be a valuable tool for detecting crevasses, allowing for a reaction time of ~9 s (equivalent to ~4.5 m on the ground) in the case of the hand-carried system and ~5 s (or ~10 m on the ground) for the tractor system.