How does surface wind behave differently from geostrophic wind?

Surface wind behaves differently from geostrophic wind primarily due to the influence of friction. At the surface, various roughness elements such as trees, buildings, and topography create drag on the wind, which causes it to deviate from the straight-line path that geostrophic wind would follow. The surface wind does not flow parallel to the isobars; instead, it crosses them at an angle due to the reduction in wind speed caused by friction.

In contrast, geostrophic wind, which occurs at higher altitudes where friction is negligible, tends to flow parallel to the isobars. This is because at those altitudes, the forces acting on the wind (the pressure gradient force and the Coriolis force) are balanced, allowing for smooth, straight-line airflow. Therefore, the correct choice captures this essential principle of how wind behaves at the surface compared to the geostrophic wind.