What atmospheric layer lies just above the tropopause and extends to an altitude of about 30 miles?

The atmospheric layer that lies just above the tropopause is the stratosphere. This layer extends from the tropopause, which typically occurs at about 8 to 15 kilometers (5 to 9 miles) above the Earth's surface, up to approximately 50 kilometers (about 30 miles) high. The stratosphere is characterized by a temperature increase with altitude, which is in contrast to the troposphere where temperature decreases with height. This temperature increase in the stratosphere is due to the presence of the ozone layer, which absorbs and scatters ultraviolet solar radiation.

The layers of the atmosphere are defined by their temperature gradients and characteristics. The incorrect options represent different layers: the troposphere is the lowest atmospheric layer where most weather occurs; the mesosphere follows the stratosphere and is where temperatures again decrease with altitude; and the thermosphere is situated above the mesosphere, featuring very high temperatures due to absorption of high-energy solar radiation. Each of these layers has distinct properties and functions, making the stratosphere the correct answer in this context for the layer located just above the tropopause.