The Briggs parameterization implies that the predicted sigma values are dependent on stability classes.

The Briggs parameterization implies that the predicted sigma values are dependent on stability classes.

• A. True
• B. False
• C. Only under complex terrain
• D. Not defined in Briggs model

Answer: (A)

The main idea is that plume spread is tied to atmospheric stability in the Briggs parameterization. In this formulation, the horizontal and vertical dispersion values (sigmas) are given as functions of downwind distance with coefficients that depend on the stability class. Different stability classes—ranging from very unstable to very stable—change how much the plume spreads at a given distance, so the same downwind distance yields different sigma values. That explicit dependence on stability class is why the predicted sigmas are not the same across all conditions. This isn’t limited to complex terrain, and the model does define sigmas through stability-based parameterization, so the statement is true.

The main idea is that plume spread is tied to atmospheric stability in the Briggs parameterization. In this formulation, the horizontal and vertical dispersion values (sigmas) are given as functions of downwind distance with coefficients that depend on the stability class. Different stability classes—ranging from very unstable to very stable—change how much the plume spreads at a given distance, so the same downwind distance yields different sigma values. That explicit dependence on stability class is why the predicted sigmas are not the same across all conditions. This isn’t limited to complex terrain, and the model does define sigmas through stability-based parameterization, so the statement is true.