What environmental factor can significantly impact the presence of turbulence as an aircraft ascends or descends?

Temperature differences are a key environmental factor affecting turbulence during an aircraft's ascent or descent. When warm air rises and cooler air descends, it creates convection currents. These air movements can lead to instability in the atmosphere. If there are significant changes in temperature at different altitudes, the resulting differences in air density will create updrafts and downdrafts, leading to turbulence.

Understanding the relationship between temperature and turbulence is crucial for pilots, as they need to anticipate areas of potential turbulence in order to ensure a smooth flight. A significant temperature gradient, such as that found near fronts or in thermal activity, will generally result in increased turbulence.

While humidity, cloud cover, and barometric pressure can also influence turbulence, they are more secondary factors. Humidity can contribute to the development of clouds and precipitation, which may indirectly affect turbulence, but temperature differences are more directly responsible for the dynamic air movements that create turbulent conditions. Similarly, while barometric pressure changes indicate weather systems that might be turbulent, it's the temperature differences that often initiate the turbulence itself.