________________________________________________________________________ 

B-1 

Appendix B

Development of Stack Parameters and Vertical Distributions for Modeling Large 

Wildfires in the CCOS Domain. 

C. Loomis 

Alpine Geophysics 

August 4, 2003 

This document describes the methodology used for vertical distribution of emissions 

estimates for the wildfires occurring during the CCOS modeling episodes. During the 

CCOS modeling episode of July 29 – August 3, 2000 two large wildfires occurred in the 

modeling domain: the July 23-31, 2000 Plaskett fire in Monterey County, and the July 

22-August 8, 2000 Manter fire in Tulare County. Daily emissions estimates and related 

parameters were calculated and provided by ARB for inclusion into the emissions 

modeling. (Scott K., 2003a, 2003b) These data were then utilized to develop a plume 

profile, using the techniques outlined in a recent report of the Fire Emissions Joint Forum 

(FEFJ) of the Western Regional Air Partnership (WRAP) (Air Sciences, 2002). The 

hourly emissions were assigned based on the following standard profile (all values are 

taken directly from the FEFJ report): 

Hour 1 2 3 4 5 6 7 8 9 10 11 12 

% 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 0.53 2.0 4.0 7.0 

Hour 13 14 15 16 17 18 19 20 21 22 23 24 

% 10.0 13.0 16.0 17.0 12.0 7.0 4.0 0.53 0.53 0.53 0.53 0.53 

For each hour of the episode, the wildfire virtual acreage was calculated using the fuel 

loading factors provided by ARB, and the virtual acreage sizes were used to determine to 

the size classes of the fires. The size classes where then used to determine the parameters 

required to calculate the plume characteristics: 

 

Class 1 2 3 4 5 

Size (virtual 

acres) 

0-10 >=10-100 >=100-1000 >=1000-5000 >=5000 

BE (size) 0.4 0.6 0.75 0.85 0.9 

Ptop Max (m) 160 2400 6400 7200 8000 

Pbot Min (m) 0 300 800 1600 1600 

 

These values, along with the buoyancy efficiency as a function of the hour of the day, 

were used to calculate the bottom of the plume, the top of the plume, and the proportion 

of the emissions fumigated into the first layer, for each grid cell in the fire area, and for 

each hour of the episode. 

To model the vertical distribution of the plumes, a series of stack parameters were 

constructed for each grid cell, and each hour of the episode. The portion of the emissions 

attributed to the plume, rather than the fumigation layer, was distributed to each of the 
________________________________________________________________________ 

B-2 

stack release points, with the fumigation portion going directly to the first layer (zero 

plume rise). The stack points were inserted into the emissions model at 25, 75 and 100 

meters, and then at every 100 meters up to the top of the plume. Emissions were evenly 

allocated to each release point, beginning in the layer corresponding to the bottom of the 

plume, and continuing to the top of the plume. 

References 

Air Sciences, Inc. 2002. 1996 Fire Emissions Inventory. Draft Final Report. Lakewood, 

CO. On-line link: 

http:/www.wrapair.org/forums/FEJF1/emissions/FEJF1996EIReport_021208.pdf 

Scott, K. 2003a. Emissions estimates for the July-August 2000 Manter Fire. Technical 

Memoradum, ARB-PTSD 

Scott, K. 2003b. Emissions estimates for the July 23-31 2000 Plaskett2 Fire. Technical 

Memoradum, ARB-PTSD