Plume Rise Calculations in AERMOD.      

PLUME RISE IN THE CBL

For the direct source, h_d is taken from (Briggs, 1984) as: 

It should be noted that u_P is the wind speed used for calculating plume rise. In the CBL u_P is set equal to u{h_s}. While in the SBL u_P is initially set equal to u{h_s} but its final value is determined by iterating.

The indirect source, which we include to treat the no flux condition at z = z_i , uses a modified reflection approach in which the reflected vertical velocity is adjusted by the addition of a plume rise term h , designed to keep the plume aloft (Weil et al., 1997), such that 

The height that the penetrated source achieves above z_i is calculated as the equilibrium plume rise in a stratified environment and is determined by the source buoyancy flux, the stable stratification above z_i , and the mean wind speed. In line with Weil et al. (1997), we assume that the plume I height h is the centroid of the plume material above the inversion and take h_ep = h_s+ h_eq for f_P = 0 or complete penetration. However, for partial penetration ( f_P > 0), h_ep is chosen as the average of the heights of the upper plume edge h_s + 1.5h_eq and z_i , or 

where h_eq is defined in eq. (68). 

6 The AMS/EPA Regulatory Model AERMOD

6.1 General Structure of AERMOD Including Terrain
6.2 AERMOD Concentration Predictions in the CBL
      6.2.1 DIRECT SOURCE CONTRIBUTION TO CONCENTRATION  
              CALCULATIONS IN THE CBL
      6.2.2 INDIRECT SOURCE CONTRIBUTION TO CONCENTRATION  
              CALCULATIONS IN THE CBL
      6.2.3 PENETRATED SOURCE CONTRIBUTION TO CONCENTRATION 
              CALCULATIONS IN THE CBL
6.3 Concentrations in the SBL Calculated by AERMOD 
6.4 Estimation of Dispersion Coefficients 
      6.4.1 AMBIENT TURBULENCE FOR USE IN CALCULATING DISPERSION
      6.4.2 BUOYANCY INDUCED DISPERSION (BID) COMPONENT OF _ AND _
              y z
      6.4.3 COMPONENT OF DISPERSION COEFFICIENTS DUE TO 
              DOWNWASH
6.5 Plume Rise Calculations in AERMOD
      6.5.1 PLUME RISE IN THE CBL 
      6.5.2 PLUME RISE IN THE SBL
6.6 Source Characterization 
6.7 Adjustments for the Urban Boundary Layer

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