Roughness length

In the logarithmic wind profile, the roughness length is the height at which wind speed is zero (indicated by z₀). It provides an estimate of the average roughness elements of the surface. With vegetated surfaces, because the vegetation itself provides a certain roughness, the logarithmic wind profile goes to zero at a height equal to the displacement height plus the roughness length.

If not entered explicitly, EddyPro computes the roughness length as

5‑2