Roughness length is a parameter of some vertical wind profile equations that model the horizontal mean wind speed near the ground. In the log wind profile, it is equivalent to the height at which the wind speed theoretically becomes zero in the absence of wind-slowing obstacles and under neutral conditions.

How do you calculate roughness length?

As an approximation, the roughness length is approximately one-tenth of the height of the surface roughness elements. For example, short grass of height 0.01 meters has a roughness length of approximately 0.001 meters. Surfaces are rougher if they have more protrusions.

What is aerodynamic roughness length?

Aerodynamic roughness length is usually defined as the height where the wind velocity is equal to zero. It is an important aerodynamic parameter and reveals the exchange between the atmosphere and land surfaces.