Tropopauza

The tropopauza, known in English as the tropopause, is the boundary between the troposphere and the stratosphere. It marks where the atmospheric lapse rate changes from the troposphere’s typically decreasing temperature with height to the more stable temperature profile of the stratosphere, warmed by ozone absorption of ultraviolet radiation. The altitude of the tropopause varies with latitude and season: typically about 8–12 km above sea level in polar regions, rising to roughly 16–18 km in the tropics, with mid-latitudes around 10–12 km. Weather systems and jet streams can locally modulate its height by a few kilometers.

Operationally, meteorological agencies define the tropopause by lapse-rate criteria: the altitude at which the environmental lapse rate falls to 2 °C per kilometer or less, measured over the preceding 1–2 kilometers. Different schemes using potential vorticity or alternative lapse-rate thresholds can yield slightly different heights.

The tropopause acts as a dynamic boundary to vertical mixing between the troposphere and stratosphere, constraining transport of water vapor and other constituents and affecting ozone distribution and chemical transport. Tropopause folds near jet streams can exchange air masses between layers, with implications for climate and atmospheric chemistry.

Measurement and observation are conducted via radiosondes on weather balloons, aircraft soundings, satellite remote sensing, and lidar. The tropopause height is used in aviation planning and is a standard parameter in climate modelling and chemical transport studies.