Model Description

 

OLD                               NEW

 

Meteorology         AVN - Aviation                RSM - Relocatable Spectral

 

H-Grid         180 km                           40 km

 

V-Grid         1000, 925, 850, ...           .99, .98, .96, .94, .92, .88, .85

 

Time            6 hour                             3 hour

 

 

 

Dispersion            HYSPLIT3                     HYSPLIT4

 

Type            Lagrangian Puff               Lagrangian Particle / Puff

 

V-Mix           K-th                                K-th

 

H-Mix          Top-hat                           K-th / Gaussian / Top-hat

 

H-Grid         Same as Meteo                Independent and variable

 

V-Grid         Same as Meteo                Independent and variable

 

 


 


                                                               MASS BALANCE

 

                                                                (Release = 340 kg)

 

 

 

Contour (ng/m3)

 

             +24h

 

              +36h

 

              +48h

 

0.05 - 0.10

 

       1.0 x 1011 m2

 

        2.6 x 1011 m2

 

        3.8 x 1011 m2

 

 

 

     1.0 x 1010 ng/m

 

       2.6 x 1010 ng/m

 

      3.8 x 1010 ng/m

 

0.10 - 0.20

 

       5.5 x 1010 m2

 

        1.4 x 1011 m2

 

        2.5 x 1011 m2

 

 

 

     1.1 x 1010 ng/m

 

       2.8 x 1010 ng/m

 

      5.0 x 1010 ng/m

 

0.20 - 0.50

 

 

 

 

 

        1.0 x 1011 m2

 

 

 

 

 

 

 

      5.0 x 1010 ng/m

 

Total

 

     2.1 x 1010 ng/m

 

       5.4 x 1010 ng/m

 

      1.4 x 1011 ng/m

 

Depth = 1000 m

 

             21 kg

 

              54 kg

 

            140 kg

 

 

 

Aircraft

 

+24h

 

Area

 

1.0 x 1011 m2

 

Concentration

 

3.5 ng/m3

 

Total

 

3.5 x 1011 ng/m

 

Depth = 1000 m

 

350 kg


 

 

                                                    SUMMARY

 

 

1) Model shows similiar horizontal and vertical plume dimensions to measurements

 

2) Model shows substantial overprediction of ground-level concentrations

 

3) Model prediction of elevated concentrations comparable to aircraft measurements

 

4) Therefore the majority of ground-level measurements must be isolated from tracer plume aloft.

 

5) Most models do not account for this decoupling, but mix tracer to the ground

 

6) Apparently greater vertical resolution is required to simulate these data correctly

 

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