What is a possible consequence of surface friction at low altitudes?

Surface friction at low altitudes affects wind behavior, primarily leading to changes in wind direction rather than speed. At lower altitudes, the presence of the Earth's surface—such as buildings, trees, and terrain—creates drag that alters the wind's movement. This friction slows down the wind speed close to the surface and can cause it to change direction as it interacts with these obstacles.

As the wind flows over uneven surfaces, it experiences turbulence, which can further influence its direction. This is especially significant in areas with varying topography or urban environments, where structures can redirect airflow. The resulting change in wind direction can have implications for flight operations, as pilots need to account for these variations when navigating and conducting approaches or departures.

While surface friction may also relate to other effects like increased wind speed aloft, the primary consequence at low altitudes fundamentally involves how the wind direction is modified due to drag and turbulence created by the surface features.