upper air

The region of the atmosphere which is above the lower troposphere; although no distinct lower limit is set, the term is generally applied to levels above that at which the pressure is 850 millibars.

Related terms:

• upper atmosphere
• upper-air chart
• upper-air sounding
• upper-air observation
• upper-air disturbance
• maritime air
• clear-air turbulence
• upper-level cyclone
• air temperature
• saturated air