High Altitude and Low Air Pressure
Regions on the Earth's surface (or in its atmosphere) that are high above mean sea level are referred to as high altitude. High altitude is sometimes defined to begin at 2,400 metres (8,000 ft) above sea level.
At high altitude, atmospheric pressure is lower than that at sea level. This is due to two competing physical effects: gravity, which causes the air to be as close as possible to the ground; and the heat content of the air, which causes the molecules to bounce off each other and expand.
Because of the lower pressure, the air expands as it rises, which causes it to cool. Thus, high altitude air is cold, which causes a characteristic alpine climate. This climate dramatically affects the ecology at high altitude.
Read more about this topic: Altitude
Famous quotes containing the words high, altitude, air and/or pressure:
“As I walked on the glacis I heard the sound of a bagpipe from the soldiers’ dwellings in the rock, and was further soothed and affected by the sight of a soldier’s cat walking up a cleated plank in a high loophole designed for mus-catry, as serene as Wisdom herself, and with a gracefully waving motion of her tail, as if her ways were ways of pleasantness and all her paths were peace.”
—Henry David Thoreau (1817–1862)
“On a level plain, simple mounds look like hills; and the insipid flatness of our present bourgeoisie is to be measured by the altitude of its “great intellects.””
—Karl Marx (1818–1883)
“But not luck
brought us here. By design
clear air and cold wind polish
the river lights, by design
we are to live now in a new place.”
—Denise Levertov (b. 1923)
“Today’s pressures on middle-class children to grow up fast begin in early childhood. Chief among them is the pressure for early intellectual attainment, deriving from a changed perception of precocity. Several decades ago precocity was looked upon with great suspicion. The child prodigy, it was thought, turned out to be a neurotic adult; thus the phrase “early ripe, early rot!””
—David Elkind (20th century)