Briggs plume rise is used to estimate which quantity in SAChE calculations?

Briggs plume rise is used to estimate which quantity in SAChE calculations?

• A. The vertical rise Δh due to buoyancy and momentum for computing H.
• B. The wind speed u.
• C. The receptor height z.
• D. The ground reflection term.

Answer: (A)

Briggs plume rise tells you how much a plume actually climbs as it leaves the stack, due to buoyancy and momentum. That vertical rise is the Δh you add to the physical stack height to obtain the effective height, H, used in the Gaussian dispersion calculations. In SAChE, H = stack height + plume rise, and this height controls how quickly the plume dilutes and where it reaches ground level. So the key quantity estimated by Briggs plume rise is that vertical rise Δh, which is then used to compute the effective height H. The other options aren’t determined by Briggs: wind speed is a separate meteorological input, receptor height is a fixed measurement in the model, and the ground reflection term is a separate correction in the dispersion equations.

Briggs plume rise tells you how much a plume actually climbs as it leaves the stack, due to buoyancy and momentum. That vertical rise is the Δh you add to the physical stack height to obtain the effective height, H, used in the Gaussian dispersion calculations. In SAChE, H = stack height + plume rise, and this height controls how quickly the plume dilutes and where it reaches ground level.

So the key quantity estimated by Briggs plume rise is that vertical rise Δh, which is then used to compute the effective height H. The other options aren’t determined by Briggs: wind speed is a separate meteorological input, receptor height is a fixed measurement in the model, and the ground reflection term is a separate correction in the dispersion equations.