A maximum in large-particle concentrations observed in the lower stratosphere between 15 and 25 km.
The top of the mesosphere and the base of the thermosphere. The mesopause is usually located at heights of 85?95 km, and is the site of the coldest temperatures in the atmosphere. Temperatures as low as 100 K (- 173?C) have been measured at the mesopause by rockets. See atmospheric shell.