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:
“The house one story high in front, three stories
On the end it presented to the road.”
—Robert Frost (1874–1963)
“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)
“The air was clear. He seemed in ultimate peace
Except that he had no eyes. Rigid and bright
Upon the forehead, furred
With a light frost, crouched an outrageous bird.”
—Anthony Hecht (b. 1923)
“This is a catastrophic universe, always; and subject to sudden reversals, upheavals, changes, cataclysms, with joy never anything but the song of substance under pressure forced into new forms and shapes.”
—Doris Lessing (b. 1919)