[1] We use the two-dimensional (2D) version of our Storm Electrification Model to test its potential for studying lightning-produced NO x . We assume that NO production is a function of energy dissipation and calculate this value from the electric field before and after each lightning flash. We use a production rate of 9.2 Â 10 16 molecules joule À1t ogenerate the NO. Using a limited set of chemical reactions involving NO, NO 2 , and O 3 , we simulated a small storm with 10 intracloud lightning flashes produced over a 2-min span. Their energy dissipation ranged between 0.024 and 0.28 GJ. The simulation was run an additional 18 min after the cessation of lightning. Our results show that the parameterization produced NO mixing ratios internal to the cloud of the order of 10 ppbv after the most energetic flashes and 1-2 ppbv in the upwind portion of the anvil toward the end of the simulation. These mixing ratios are shown to be comparable to observations in a generic sense. Comparison with the C-shaped profiles developed by Pickering et al.[1998], also using a 2D model, show similarities, but our results are more weighted toward larger values at higher altitudes than those of Pickering et al. This may be due to differences in the length of the simulation, a lack of cloud-to-ground lightning in our work, a lack of reactive chemistry in Pickering et al., or the use by Pickering et al. of the assumption of Price et al. [1997] that intracloud flashes dissipate one tenth the energy of cloud-to-ground flashes. We show, using recent observational data and an analysis of the assumptions of Price et al., that this one tenth energy dissipation assumption is not appropriate. We conclude that our use of an explicit lightning scheme to study NO production at the process level is a viable methodology. Citation: Zhang, X., J. H. Helsdon Jr., and R. D. Farley, Numerical modeling of lightning-produced NO x using an explicit lightning scheme: 1. Two-dimensional simulation as a ''proof of concept'',

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[1] We continue the development of a modeling system for the investigation of lightningproduced NO x at the process level by including the chemistry aspects used in the companion paper [Zhang et al., this issue] (hereinafter referred to as Part 1) in the threedimensional version of our Storm Electrification Model. Looking toward longer simulations, we expand the chemistry to include CO, CH 4 , OH, and HO 2 , with HNO 3 as a sink. As in Part 1, we simulate the 19 July 1981 CCOPE cloud using noninductive charging for electrification, producing 18 intracloud lightning flashes over a 3-min period. The simulation ends at 38 min with the cloud dissipating. Energy dissipation due to lightning in this simulation ranges between 0.91 and 2.28 GJ. Results show a maximum NO mixing ratio of 35.8 ppbv produced by lightning during the simulation. As the cloud dissipates, following the cessation of lightning, there are maxima for both NO and NO 2 of $6.3 ppbv around 4 km altitude. The NO mixing ratio in the anvil peaks around 2 ppbv near 10.5 km. These results are in reasonable agreement with available observations. A striking feature is a plume of NO 2 with mixing ratios of the order of 0.5 ppbv reaching the surface. There is no similar plume for NO. Likewise, NO from the core of the cloud is transported into the anvil, while NO 2 does not exhibit the same behavior, probably as a result of photolysis. The NO 2 /NO ratio is found to decrease with altitude and is comparable to estimates derived from observations. The NO production per unit length (mean = 2.03 Â 10 22 molecules m À1 ) is also within the range of estimated values. Our results indicate that short-lived storms may produce a vertical profile of NO x that differs from the C-shaped profiles of Pickering et al. [1998]. Citation: Zhang, X., J. H. Helsdon Jr., and R. D. Farley, Numerical modeling of lightning-produced NO x using an explicit lightning scheme: 2. Three-dimensional simulation and expanded chemistry,

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