ATPL Canadian Meteorology, Radio Aids to Navigation, and Flight Planning (SAMRA) Practice Test

The temperature lapse rate is defined as the rate at which temperature decreases with an increase in altitude in the atmosphere. In the case of the tropopause, which is the boundary between the troposphere and the stratosphere, a distinct change occurs: temperatures stabilize or even increase with altitude in the stratosphere, contrasting with the decrease in the troposphere.

When you experience a change in temperature while climbing, particularly if you notice that the temperature no longer decreases and instead begins to rise with altitude, this is a clear indication of reaching the tropopause. As you ascend through the troposphere, the temperature typically drops, but at the tropopause, this trend reverses or levels off, marking a significant change in the lapse rate.

This phenomenon is essential for understanding weather patterns, as it is at the tropopause where many weather systems and turbulence are influenced by the varying temperature profiles above and below this boundary. The other options, while related to meteorological phenomena, do not specifically indicate a change in the lapse rate at the tropopause the way a change in temperature during a climb does.