Which of the following can decrease the severity of wake turbulence effects?

Increased altitude can indeed decrease the severity of wake turbulence effects. This is primarily because wake turbulence generally dissipates with distance from the generating aircraft. As altitude increases, the vertical and horizontal separation between aircraft also tends to increase, which allows the wake turbulence from one aircraft to dilute more effectively before affecting another aircraft flying at a higher altitude.

Aircraft wake turbulence primarily descends and spreads out laterally as it moves downwind. Therefore, by flying at a higher altitude, subsequent aircraft are likely to encounter less turbulent air, resulting in a smoother passage through what may have otherwise been disturbed airspace.

The context of wake turbulence is essential for air traffic control and flight safety. Aircraft flying at higher altitudes may have a reduced risk of encountering wake turbulence, which can be especially critical during approach and landing phases when aircraft are closer together.