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)
“If you love music, hear it; go to operas, concerts and pay fiddlers to play to you; but I insist on your neither piping nor fiddling yourself. It puts a gentleman in a very frivolous, contemptible light.... Few things would mortify me more than to see you bearing a part in a concert, with a fiddle under your chin, or a pipe in your mouth.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)
“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)
“Clay answered the petition by declaring that while he looked on the institution of slavery as an evil, it was ‘nothing in comparison with the far greater evil which would inevitably flow from a sudden and indiscriminate emancipation.’”
—State of Indiana, U.S. public relief program (1935-1943)