Stratosphere

The stratosphere is the layer above the troposphere, characterized primarily as a stable, stratified layer (hence, stratosphere) with a large temperature inversion throughout (see chart on page 1). The main impact the stratosphere has on weather is that its stable air prevents large storms from extending much beyond the tropopause.

The other main impact important to life deals with ozone. Ozone is the triatomic form of oxygen that absorbs ultraviolet(UV) light and prevents it from reaching the earth's surface at dangerous levels. The stratosphere contains the ozone layer that has been such a hot topic as of late. The maximum concentrations of ozone are at about 25 km (15 miles) above the surface, or near the middle of the stratosphere. The interaction between UV light, ozone, and the atmosphere at that level releases heat, warming the atmosphere and helping to create the temperature inversion in this layer.

The stratosphere is bounded above by the stratopause, where the atmosphere again becomes isothermal. The average height of the stratopause is about 50 km, or 31 miles. This is about the 1 mb (0.1 kPa) pressure level. The layer above the stratosphere is the mesosphere.