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:
“Wind and Thistle for pipe and dancers
And never a ploughman under the Sun.
Never a ploughman. Never a one.”
—Hilaire Belloc (1870–1953)
“On a cloud I saw a child,
And he laughing said to me,
“Pipe a song about a Lamb”;
So I piped with merry chear.
“Piper pipe that song again”—
So I piped, he wept to hear.
“Drop thy pipe thy happy pipe
Sing thy songs of happy chear”;
So I sung the same again
While he wept with joy to hear.”
—William Blake (1757–1827)
“After the planet becomes theirs, many millions of years will have to pass before a beetle particularly loved by God, at the end of its calculations will find written on a sheet of paper in letters of fire that energy is equal to the mass multiplied by the square of the velocity of light. The new kings of the world will live tranquilly for a long time, confining themselves to devouring each other and being parasites among each other on a cottage industry scale.”
—Primo Levi (1919–1987)
“By the flow of the inland river,
Whence the fleets of iron have fled,
Where the blades of the grave-grass quiver,
Asleep are the ranks of the dead:—”
—Francis Miles Finch (1827–1907)