Tracer and Chemistry Modeling of Thunderstorms for the DC3 Field Experiment

The Deep Convective Clouds and Chemistry (DC3) field campaign was conducted during May and June 2012 over the central US. The goals of DC3 are to quantify 1) storm dynamical, physical, and electrical characteristics, as well as convective transport of chemical constituents in active thunderstorms, and 2) changes in chemistry and composition of the upper troposphere (UT) after active convection. Storms were sampled by three aircraft in three regions, northern Alabama, west Texas to central Oklahoma, and northeast Colorado, allowing the DC3 team to contrast a variety of storm types and airmass composition. For a successful campaign, accurate forecasts of storm location and timing were needed. The Weather Research and Forecasting (WRF) model was the primary tool for making these forecasts. During the field operation, boundary layer (BL) and lightning-NOx (LNOx) tracers were included with the WRF forecasts to predict where the upper troposphere air would travel to over the next day's time. During the post-campaign period, WRF simulations coupled with chemistry (WRF-Chem) have begun to evaluate the representativeness of the storms, convective transport of trace gases, and transport and chemistry in the UT downwind of the active convection. In this study, we present a summary of the WRF-tracer forecasts, illustrating how the BL and LNOx tracers were used to plan flights downwind of the active storms. We then focus on the May 29, 2012 case study of an Oklahoma severe storm by providing a description of the storm, its environment, and trace gas measurements. Results from the WRF-Chem simulation are then evaluated with these preliminary measurements.