What effect does surface friction have on wind at ground level?

Surface friction plays a significant role in how wind behaves as it moves across the Earth's surface. At ground level, the unevenness of the terrain, the presence of buildings, trees, and other obstacles creates friction that interacts with the flow of air. This interaction effectively slows down the wind.

As wind encounters these surface roughness elements, it loses kinetic energy due to frictional forces. The result is a reduction in wind speed compared to higher altitudes where friction is minimal. This is why, at lower altitudes, the wind experiences a notable decrease in speed. Additionally, the presence of obstacles can create turbulence and uneven wind patterns close to the ground, further affecting its flow.

Therefore, the understanding that surface friction slows down wind at ground level is crucial for predicting local weather patterns, understanding how winds can change with terrain, and for aviation safety regarding takeoffs and landings near an airport.