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, sheet and/or flow:
“Pretty friendship ‘tis to rhyme
Your friends to death before their time
Moping melancholy mad:
Come, pipe a tune to dance to, lad.””
—A.E. (Alfred Edward)
“You take the lake. I look and look at it.
I see it’s a fair, pretty sheet of water.
I stand and make myself repeat out loud
The advantages it has....”
—Robert Frost (1874–1963)
“On the idle hill of summer,
Sleepy with the flow of streams,”
—A.E. (Alfred Edward)