Other Levels » Tropopause Definition
Definition: Tropopause
The tropopause is defined as the boundary between the troposphere and the stratosphere. It is usually marked by a significant change in lapse rate from less stable below in the troposphere to very stable above in the stratosphere.
Its height varies from 10 km or lower in polar regions to as high as 20 km in the tropics.
Since the temperature gradient reverses from cooling with increased height in the troposphere to warming with increased height in the stratosphere, the maximum wind speed is typically observed at or near the tropopause level.
The tropopause is a mandatory reported level for most rawinsonde soundings.