mesosphere

Adjective modifier

• upper: Recent observational evidence indicates a systematic reduction in gravity wave fluxes in the upper mesosphere and lower thermosphere from solar minimum to solar maximum.
• polar: That is why the summer polar mesosphere is the coldest place on earth despite also being the sunniest.

Noun used with modifier

• summer: Gravity waves seem practically certain to be important for several aspects of this picture, beyond their widely accepted role in the summer mesosphere.