What characterizes the tropopause?

The tropopause is characterized by an abrupt change in the rate of temperature change, marking the transition between the troposphere and the stratosphere. In the troposphere, temperature typically decreases with altitude due to the presence of weather phenomena and the influence of Earth's surface. However, at the tropopause, this trend reverses, and temperature stabilizes or begins to increase in the stratosphere above. This shift creates a distinct boundary, which is why an abrupt change, rather than a gradual one, defines the tropopause.

Sustained decrease in pressure is a phenomenon associated with atmospheric layers but does not specifically describe the tropopause's characteristics. The other options suggest temperature changes that do not align with the sharp contrast in temperature profiles observed at this boundary layer.