CB05 Mechanism Notes - September 27, 2006 An updated Carbon Bond (CB05) mechanism has been developed for use with the CMAQv4.6. The CB05 mechanism has been described in details by Yarwood et al. (2005). The CB05 mechanism contains 156 reactions involving 52 species. The CB05 mechanism has been implemented into the CMAQ model and an Euler Backward Solver (EBI) solver has been developed for the CB05 mechanism. In-house tests were conducted using the CB05 and CB4 mechanisms for summer and winter of 2001 using the 36-km continental US domain. Initial test results indicate that predicted ozone concentrations increase with the CB05 mechanism by about 8% compared to the CB4 mechanism in summer. Predicted ozone concentrations increase only by about 1% in winter compared to the CB4 mechanism. Detailed comparisons of the CMAQ results with the CB05 and CB4 mechanisms have been described by Sarwar et al. (2006). SMOKE The Sparse Matrix Operator Kernel Emissions (SMOKE) System is needed to generate model-ready CB05 emissions. The SMOKE system can generate model-ready CB05 emissions using the gspro file that has been developed for the CB05 mechanism. The gspro file is included in the $M3HOME/data/raw/emis directory. References: Sarwar, G., D. Luecken, G.Yarwood, G. Whitten, and W. P.L. Carter, 2006. Impact of an Updated Carbon Bond Mechanism on Predictions from the Community Multiscale Air Quality Model, submitted to the Journal of Applied Meteorology and Climatology. Yarwood, G., S. Rao, M. Yocke, and G. Whitten, 2005, Updates to the Carbon Bond Chemical Mechanism: CB05. Final Report to the US EPA, RT-0400675. Available at http://www.camx.com/publ/pdfs/CB05_Final_Report_120805.pdf.