What causes the difference in wind direction and speed between 2000 feet AGL and the surface?

The difference in wind direction and speed between 2000 feet AGL and the surface is primarily caused by the effects of the earth's surface and surface friction. At lower altitudes, the wind is significantly influenced by the interaction with the terrain and other surface features, such as buildings, trees, and natural landforms.

Surface friction slows down the wind as it flows over these features, causing a reduction in speed compared to the wind at higher altitudes, where such frictional effects are minimal. As a result, at 2000 feet AGL, the wind tends to move more swiftly and smoothly, often under the influence of larger atmospheric patterns without the impediments caused by the surface.

This phenomenon explains why wind direction can also differ between various altitudes; the friction effects at the ground level can cause wind to blow at different angles compared to the more unobstructed flow of wind higher up in the atmosphere. The nuances of terrain and friction combine to create a distinct change in both speed and direction from the surface to higher altitudes, which is a crucial concept in understanding wind behavior in aviation.