Science / Weather / Atmosphere: The gaseous or air portion of the physical environment that encircles a planet. In the case of the earth, it is held more or less near the surface by the earth's gravitational attraction. The divisions of the atmosphere include the troposphere, the stratosphere, the mesosphere, the ionosphere, and the exosphere.
Science / Weather / Standard Atmosphere: A standard atmosphere has been defined by the International Civil Aeronautical Organization (ICAO). It assumes a mean sea level temperature of 15°C a standard sea level pressure of 1,013.25 millibars MORE
Technology / Aviation / Standard Air (Standard Atmosphere): An arbitrary atmosphere established for calibration of aircraft instruments. Standard Air Density is 29.92 inches of mercury and temperature of 59° F, equivalent to an atmospheric air pressure of 14. MORE