Potential ozone production following convective transport based on future emission scenarios

Abstract

Current and projected (up to 2050 A.D.) concentrations of boundary layer trace gases, including NOx, CO, CH₄, and several nonmethane hydrocarbons were redistributed throughout the troposphere in a simulation of a central U.S. squall line using the Goddard Cumulus Ensemble (GCE) convective cloud model. Vertical profiles of the redistributed trace gases were used in a one-dimensional photochemical model to determine the vertical profile of the potential production of 0₃. Several different emission scenarios were considered. In the case where NOx emissions were doubled along with an increase in CO, CH₄, and NMHC's, the middle troposphere showed an enhancement of 41% for O₃ production relative to the 1985 case. For the reduction scenario, where NOx emissions were decreased by a factor of two, the O₃ produced in the middle troposphere was reduced by 50%. Given the role of convection in the regional O₃ budget of the central U.S. during the summertime, our results suggest that substantial changes in emissions could bring about changes in mid-tropospheric O₃ large enough to be observed by satellite remote sensing.