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)
“All I’m telling you is that that little creature in there has as much right to live as you do. Don’t forget, you invaded his world. You sank a pipe six miles into the ground and when he climbed up you set dogs on him, shot him.”
—Richard Fielding, and Lee Sholem. Superman (George Reeves)
“Time that scatters hair upon a head
Spreads the ice sheet on the shaven lawn;
Signing an annual permit for the frost....”
—Philip Larkin (1922–1986)
“On the idle hill of summer,
Sleepy with the flow of streams,”
—A.E. (Alfred Edward)