What is a "wind shear"?

Wind shear refers to a sudden change in wind speed or direction, which can occur at various altitudes in the atmosphere. This phenomenon is particularly significant because it can have various impacts on aviation and maritime activities, affecting stability and control. For example, during takeoff and landing phases, pilots must be aware of wind shear conditions, as they can lead to unexpected changes in lift and drag on the aircraft. Similarly, sailors may need to be cautious of wind shear when navigating, as it can affect sail stability and the handling of the vessel.

Understanding wind shear is crucial because it highlights the dynamic nature of wind and its potential for causing difficulties during operations. The other options describe different aspects of wind behavior that do not capture the abruptness and variability inherent in wind shear conditions.