This term is used in the glaciological literature to refer to the melting point of ice under pressure. As the pressure increases in the downward direction, the melting temperature of ice decreases. This pressure melting point can reach values many degrees below 0°C.
Due to geothermal heat flux from below, the temperature at the same time increases. The level where ice can start melting is where the pressure melting point equals the actual temperature. In static equilibrium conditions, this would be the highest level where water can exist in a glacier. It would also be the level of the base of an ice shelf, or the ice-water interface of a subglacial lake.
Famous quotes containing the words pressure, melting and/or point:
“We believe that civilization has been created under the pressure of the exigencies of life at the cost of satisfaction of the instincts.”
—Sigmund Freud (1856–1939)
“Slow, slow, fresh fount, keep time with my salt tears;
Yet slower yet, oh faintly gentle springs:
List to the heavy part the music bears,
“Woe weeps out her division when she sings.”
Droop herbs and flowers;
Fall grief in showers;
“Our beauties are not ours”:
Oh, I could still,
Like melting snow upon some craggy hill,
Drop, drop, drop, drop,
Since nature’s pride is, now, a withered daffodil.”
—Ben Jonson (1572–1637)
“What we call little things are merely the causes of great things; they are the beginning, the embryo, and it is the point of departure which, generally speaking, decides the whole future of an existence. One single black speck may be the beginning of a gangrene, of a storm, of a revolution.”
—Henri-Frédéric Amiel (1821–1881)