adiabatic atmosphere

adiabatic atmosphere

[¦ad·ē·ə¦bad·ik ′at·mə‚sfir]
(meteorology)
A model atmosphere characterized by a dry-adiabatic lapse rate throughout its vertical extent.

homogeneous atmosphere

i. A hypothetical atmosphere in which the gaseous composition is constant with height. The lapse rate of temperature in such an atmosphere is known as the autoconvective lapse rate and is equal to approximately 15°F/1000 ft (3.4°C/100 m). For a surface temperature of –32°F (273 K), the vertical extent of the homogeneous atmosphere on the earth is approximately 25,000 ft (8 km). At the top of such an atmosphere both the pressure and absolute temperature vanish.
ii. With respect to radio propagation, an atmosphere that has a constant index of refraction, or one in which radio waves travel in straight lines at a constant speed. Free space is the ideal homogeneous atmosphere in this sense.
iii. The same as adiabatic atmosphere.
homopause The top of the homosphere, or the level of transition between it and the hetrosphere. The homopause probably lies between 50 and 55 miles (80 and 90 km), where molecular oxygen begins to dissociate into atomic oxygen. The homopause is somewhat lower in the daytime than at night. See hetrosphere.