To examine the uncertainties in modeling the impact of lightning NOx production and convective on upper tropospheric chemical tracer distributions, we apply a regional-scale model (REAM) driven by two meteorological models, WRF and MM5, with different cumulus convective parameterizations. The model simulations are evaluated using INTEX-A aircraft measurements and satellite measurements of NO2 columns and cloud top pressure, and we find that mid and upper tropospheric trace gas concentrations are affected strongly by convection and lightning NOx production. The inclusion of the entrainment and detrainment processes leads to more outflow in the mid troposphere and lower lightning NOx distribution in WRF than MM5. At 8-12 km, the models simulate a contribution of 60-75% of NOx and up to 20 ppbv of O3 from lightning, although the decrease of lightning NOx effect from the Southeast to Northeast and eastern Canada is overestimated. The model differences and biases found reflect some major uncertainties of upper tropospheric NOx and O3 simulations driven by those in meteorological simulations and lightning parameterizations.

A priori profiles, derived from chemical transport models, are essential to retrieve satellite observations of NO2. This reliance arises from the satellite’s inability to determine the vertical structure of NO2 in the atmosphere from the altitude dependence of satellite sensitivities to NO2. Two sets of a priori profiles are used in comparison here: TM4 and REAM. TM4 is a global model run by the Koninklijk Nederlands Meteorologisch Instituut (KNMI) with approximately 2°x3° resolution and 23 vertical levels in the troposphere. The REAM regional model has higher resolutions (36 km and 30 vertical layers). We find that both lightning NOx and model resolution have significant effects on satellite vertical column retrievals of tropospheric NO2. The a priori profiles with lightning NOx may result in a 25-50% reduction of the retrieved tropospheric NO­2 vertical columns compared to the a priori profiles without lightning.