What is the thin outer layer of the troposphere that marks the boundary between the troposphere and the statosphere?

The thin outer layer of the troposphere that marks the boundary between the troposphere and the stratosphere is called the tropopause. It acts as a transition zone where temperature stops decreasing with altitude and begins to increase in the stratosphere. The altitude of the tropopause varies with latitude and weather conditions, typically found at around 8 to 15 kilometers (5 to 9 miles) above sea level.