In rural Briggs parameterization, the surface roughness length used for passive plume dispersion corresponds to which landscape type?

In rural Briggs parameterization, the surface roughness length used for passive plume dispersion corresponds to which landscape type?

• A. Open water
• B. Grassland
• C. Urban area
• D. Dense forest

Answer: (B)

The surface roughness length in the rural Briggs parameterization is chosen to reflect the typical roughness of the ground over which the plume disperses. In rural areas, open grassland represents the common landscape, providing a moderate level of surface roughness that drives the near-surface wind shear and turbulence used by the parameterization to estimate dispersion. Open water has a much smaller roughness length, which would imply less mechanical mixing; urban areas and dense forests have much larger roughness lengths due to buildings and tree canopies, which are not representative of rural terrain. Therefore, grassland best matches the conditions Briggs uses for passive plume dispersion in rural settings.

The surface roughness length in the rural Briggs parameterization is chosen to reflect the typical roughness of the ground over which the plume disperses. In rural areas, open grassland represents the common landscape, providing a moderate level of surface roughness that drives the near-surface wind shear and turbulence used by the parameterization to estimate dispersion. Open water has a much smaller roughness length, which would imply less mechanical mixing; urban areas and dense forests have much larger roughness lengths due to buildings and tree canopies, which are not representative of rural terrain. Therefore, grassland best matches the conditions Briggs uses for passive plume dispersion in rural settings.