Wartime Investigation of the Greenland Icecap and Its Possibilities

Wade, F. Alton

doi:10.2307/210828

Cited by 4 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The team’s mission was first to establish a coastal base camp in southeast Greenland and then to establish stations on the ice cap from which small teams could travel by snow machine to rescue fliers whose planes went down on the ice. Wade (1946) included photos and maps from the mission.…”

Section: Birth and Life Of Free Extrusion Flowmentioning

confidence: 99%

Life, death and afterlife of the extrusion flow theory

Waddington

2010

J. Glaciol.

View full text Add to dashboard Cite

Extrusion flow' describes any velocity field where maximum horizontal velocity occurs below the surface. By 1914, viscous flow and basal sliding over rough beds were accepted concepts. Between the world wars, there was little communication between naturalists describing complicated ice sheets, and physicists studying fundamental processes controlling flow. Max Demorest brought concepts from mechanics into glaciology and glacial geology; however, his extrusion flow theory, to explain how ice flowed out of central Greenland, overlooked force imbalance. Rudolf Streiff-Becker found an apparent large imbalance between ice flux discharged through a gate and net accumulation in the upstream catchment at Claridenfirn, Switzerland. Because he underestimated uncertainty in ice depth, he had to propose a strong undercurrent (extrusion flow) to evacuate the excess mass. Reassessment of his assumptions shows that extrusion was actually unnecessary. However, confluence of two lines of evidence for extrusion flow added stature to the concept. In 1952, John Nye showed that free extrusion flow was impossible due to force imbalance. Two forms of extrusion flow survive: capped extrusion flow is possible on local scales where longitudinal stress gradients allow upper ice to move slowly, and rigidbody rotational flow can allow deeper ice to move faster without strain. DilatationJohann Jakob Scheuchzer, a physicist from Zü rich, proposed the dilatation theory of glacier flow. According to the dilatation theory, meltwater flowed into the interstices and

show abstract

Section: Birth and Life Of Free Extrusion Flowmentioning

confidence: 99%