Grantee Research Project Results

Sensitivity of CMAQ simulations to prescribed burn emissions under varied plume core numbers.

Citation:

Liu Y, Achtemeier GL, Goodrick SL. Sensitivity of CMAQ simulations to prescribed burn emissions under varied plume core numbers. In:Proceedings of EPA’s 16th Annual International Emission Inventory Conference, Emission Inventories: Integration, Analysis, and Communications, Raleigh, NC, May 14-17, 2007.

Abstract:

Recent studies with Daysmoke indicate the importance of plume-core number for smoke transport and dispersion processes. Since Daysmoke is a tool used to estimate plume rise and vertical distribution of smoke particles for our CMAQ simulations of prescribed burns, it is expected that the CMAQ simulations would be sensitive to plume-core number. This study seeks to understand this sensitivity. An experiment is first conducted using the Fourier amplitude sensitivity test (FAST) to identify the most important parameters in the calculation of plume rise with Daysmoke. This technique determines the relative contribution of individual model input parameters to the variance of the model output. A set of 13 parameters is examined with a range of values for each parameter specified based on measurements of prescribed burning or empirical estimates. The result indicates that plume-core number is among the most important parameters for the estimation of plume rise. CMAQ simulations of a prescribed burn are then conducted with different plume-core numbers. The burn was implemented at the Brush Creek unit of the Cherokee National Forest near the Tennessee-North Carolina border on March 18, 2006 with about 1656 acres burned. Fire emissions are estimated using a forest fuel and fire modeling scheme. The atmospheric conditions are obtained from an MM5 simulation. It is shown that the simulations are significantly dependent on the plume-core number. The simulated ground PM concentrations are remarkably larger for multiple-core smoke updraft than single-core one.