ABSTRACT
An important consideration in making dispersion estimates is to use the proper effective height of emission above the ground. The period required to dissipate the excess temperature will vary with both the nature of the plume release and with atmospheric conditions, but generally will require at least three or four minutes. Because of the short duration of the momentum rise, the momentum-dominated plume is assumed to have achieved its final rise very near the source and gradual rise is seldom considered. If the rise is calculated to be more than the rise from the appropriate equation above for final rise, then it is being applied for a distance beyond the distance to final rise and the final rise value should be substituted. In formulating the TUPOS model for elevated buoyant releases, Turner modified Briggs equations so that plume rise could be calculated layer-by-layer so that the effects of changing vertical structure of wind and temperature could be included.
