upper mixing layer

The region of the upper mesophere between about 30 and 50 miles (50 and 80 kilometers; that is, immediately above the mesopeak) through which there is a rapid decrease of temperature with height and where there appears to be considerable turbulence.

Related terms:

• F2 layer
• upper-atmosphere dynamics
• boundary layer
• E layer
• D layer
• F1 layer
• isothermal layer
• saturation mixing ratio
• upper mantle
• layer