distribution in convectively mixed layers. The specific form for the concentration distribution in

the CBL is found in eq. (54) which uses the notation

Cc{xr, yr, zr}. Similarly, in the SBL, theconcentration takes the form of eq. (67) and used the notation

Cs{xr, yr, zr}.AERMOD simulates five different plume types depending on the atmospheric stability and

on the location in and above the boundary layer: 1) direct, 2) indirect, 3) penetrated, 4) injected

and 5) stable. All of these plumes will be discussed, in detail, throughout the remainder of this

document. During stable conditions, plumes are modeled with the familiar horizontal and

vertical Gaussian formulations. During convective conditions (

L<0) the horizontal distributionis still Gaussian; the vertical concentration distribution results from a combination of three

plume types: 1) the direct plume material within the mixed layer that initially does not interact

with the mixed layer lid; 2) the indirect plume material within the mixed layer that rises up and

tends to initially loft near the mixed layer top; and 3) the penetrated plume material that is

released in the mixed layer but, due to its buoyancy, penetrates into the elevated stable layer.

During convective conditions, AERMOD also handles a special case referred to as an

injected source where the stack top (or release height) is greater than the mixing height. Injected

sources are modeled as plumes in stable conditions, however the influence of the turbulence and

the winds within the mixed layer are considered in the inhomogeneity calculations as the plume

material passes through the mixed layer to reach receptors.

As described above, AERMOD accounts for the vertical variation of meteorology through

the use of effective values of wind speed, turbulence, and the Lagrangian time scale. Being a

steady state plume model, AERMOD uses a single value of each meteorological variable to

represent the state of the dispersive layer for each modeling period (typically one hour).

Specifically, the effective parameters are determined by averaging values from the meteorological

profile within the layer between the plume’s center of mass and the receptor. Effective variables

or parameters are denoted by an overbar tilde (e.g.

u~ ).

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castellano: DISPER CUSTIC DESCAR RADIA italiano:

castellano: DIS CUS DES RAD english: DIS CUS DES RAD

português: DIS CUS DES RAD italiano: DIS CUS DES RAD