tropopause

The transition layer between the troposphere and stratosphere, usually characterized by a distinct change of atmospheric stability, atmospheric composition, and/or atmospheric dynamics.

The change is in the direction of increased atmospheric stability in the stratosphere, spanning a layer from tens of meters to several kilometers in depth, depending on region and weather situation. Its height varies from 14 to 19 km (9–12 miles) in the tropics to 10 km (6 miles) in the extratropics, reaching sometimes as low as 5 km (3 miles). A sharp discontinuity in tropopause height exists near the subtropical jet stream in each hemisphere and is often referred to as the “tropopause break.” Smaller discontinuities are found near higher-latitude jet streams. In the extratropics, the tropopause is typically characterized by a strong temperature inversion a few kilometers in depth which is referred to as the “tropopause inversion layer.” The tropopause can become highly deformed and difficult to identify in dynamic situations and in polar regions in winter, since under such conditions changes in stability, composition, and dynamics are not abrupt at any height. It is also common for multiple tropopauses to exist in a profile, similarly revealed as overlapping distinct changes in atmospheric stability, atmospheric composition, and/or atmospheric dynamics.

Term edited 24 July 2026.