Stratopause

The stratopause is the atmospheric boundary between Earth's stratosphere and mesosphere. It marks the upper limit of the stratosphere and the lower boundary of the mesosphere. The name reflects its nature as a boundary within the stratified layers of the atmosphere.

The stratopause is characterized by a maximum in the stratosphere’s temperature profile. In the stratosphere, temperature generally increases with altitude due to ozone absorbing ultraviolet radiation; at the stratopause, this warming ceases and the temperature begins to fall with height in the mesosphere below. The altitude of the stratopause is not fixed; it sits at about 50 kilometers on average but varies with latitude and season, being roughly 45–50 km near the equator and rising toward polar regions to around 60 km or more.

Observation and study of the stratopause involve radiosondes (weather balloons), satellites, and other remote-sensing techniques. Its height and temperature are influenced by atmospheric waves, solar activity, ozone distribution, and long-term climate variations. Understanding the stratopause helps researchers characterize the overall temperature structure of the middle atmosphere and its role in atmospheric chemistry and dynamics.