What type of turbulence is characterized by a stable flow of air over mountains?

Mountain waves are a specific type of turbulence that occurs as air flows over mountain ranges. When stable air is forced to ascend and descend over the terrain, a series of waves can form in the atmosphere, leading to turbulence that is often felt by aircraft flying at higher altitudes. This phenomenon is particularly pronounced when the air is stable, allowing the waves to propagate smoothly, and can produce significant vertical oscillations in the airflow.

In contrast, clear air turbulence typically occurs at high altitudes away from thunderstorms, often caused by wind shear in the jet stream, while mechanical turbulence is created by the effects of wind interacting with the earth's surface, such as buildings and terrain. Convective turbulence is associated with the rising and falling currents of warm air, which are linked to convective weather patterns. In summary, mountain waves specifically pertain to the interaction of stable air with mountainous regions, making the correct choice evident.