Particulate Emissions Modeling

Particulate emissions modeling will be done using the BlueSky smoke modeling framework. For this component of the study, we have sought out the expertise of the Southern High Resolution Modeling Consortium (SHRMC), one of the U.S. Forest Service's Fire Consortia for Advanced Modeling of Meteorology and Smoke (FCAMMS). SHRMC scientists will feed our data on fuel loading, consumption and emissions into the BlueSky framework and provide us with GIS files depicting expected surface PM 2.5 concentrations. For each case BlueSky will be run with model resolutions of 12, 4 and 1.3 kilometers to assess the importance of model resolution. Additional sensitivity experiments will be conducted on the general BlueSky inputs of initial fuel loading, fuel consumption and emission factors. The BlueSky model will also be used to investigate various scenarios of burning by introducing a series of simulated burn patterns into the model under varying atmospheric and fuel load conditions. These model runs will help define climatological relationships between spatio-temporal burn patterns and PM2.5 concentrations in the target cities.

A key component of BlueSky to be evaluated is the Emissions Production Model or EPM. EPM is used by BlueSky to partition the total emissions from a fire in time based on factors that were determined to control biomass consumption and combustion efficiency for the prescribed burning of logging debris in the Pacific Northwest. The appropriateness of this model for estimating time-dependent emissions from prairie fires has not been extensively tested. EPM is essentially the fitting of a curve by controlling various time scale parameters; the area under this curve represents the total emissions from the fire. As an additional numerical experiment, SHRMC scientists will evaluate the sensitivity of BlueSky output to the specification of these time parameters as well as determining the overall effectiveness of EPM in describing time-dependent emissions from prairie fires based on observations recorded during this study.