Pipe and Sheet Flow
The flow of water under the glacial surface can have a large effect on the motion of the glacier itself. Subglacial lakes contain significant amounts of water, which can move fast: cubic kilometres can be transported between lakes over the course of a couple of years.
This motion is thought to occur in two main modes: pipe flow involves liquid water moving through pipe-like conduits, like a sub-glacial river; sheet flow involves motion of water in a thin layer. A switch between the two flow conditions may be associated with surging behaviour. Indeed, the loss of sub-glacial water supply has been linked with the shut-down of ice movement in the Kamb ice stream. The subglacial motion of water is expressed in the surface topography of ice sheets, which slump down into vacated subglacial lakes.
Read more about this topic: Ice Sheet Dynamics
Famous quotes containing the words pipe and, pipe, sheet and/or flow:
“I am dead against art’s being self-expression. I see an inherent failure in any story which fails to detach itself from the author—detach itself in the sense that a well-blown soap-bubble detaches itself from the bowl of the blower’s pipe and spherically takes off into the air as a new, whole, pure, iridescent world. Whereas the ill-blown bubble, as children know, timidly adheres to the bowl’s lip, then either bursts or sinks flatly back again.”
—Elizabeth Bowen (1899–1973)
“Pan’s Syrinx was a girl indeed,
Though now she’s turned into a reed;
From that dear reed Pan’s pipe does come,
A pipe that strikes Apollo dumb;
Nor flute, nor lute, nor gittern can
So chant it, as the pipe of Pan;”
—John Lyly (1553–1606)
“A speck that would have been beneath my sight
On any but a paper sheet so white
Set off across what I had written there.”
—Robert Frost (1874–1963)
“Learning and teaching should not stand on opposite banks and just watch the river flow by; instead, they should embark together on a journey down the water. Through an active, reciprocal exchange, teaching can strengthen learning how to learn.”
—Loris Malaguzzi (1920–1994)