We present an integrated analysis of measurements from ozonesonde, ozone (O3) Differential Absorption Lidar (DIAL), ceilometer, surface monitors, and space-borne observations in conjunction with the regional chemical transport model Weather Research and Forecast Model with Chemistry (WRF-Chem) to investigate the effect of biomass burning emissions on the vertical distribution of ozone and aerosols during an episode of the 2016 Southeastern United States wildfires. The ceilometer and DIAL measurements capture the vertical extent of the smoke plumes affecting the surface and upper air over Huntsville, AL. The model evaluation results suggest a scaling factor of 3-4 for the wildfire aerosol emissions to better match observed aerosol optical depth (AOD), fine particulate matter (PM2.5), and DIAL aerosol extinction. We use the scaled emissions together with WRF-Chem tendency diagnostics to quantify the fire impacts and characterize the processes affecting the vertical ozone budget downstream of the wildfires. During the daytime at Huntsville on 12 and 13 November, we estimate that fire emissions contribute 12-32 μg/m3 (44-70%) to hourly surface PM2.5 and 7-8 ppb/10 hrs (30-37%) to the surface ozone increase (∆O3), respectively. Net chemical ozone production (PO3) is the main contributor to upper-air ozone, which reaches 17-19 ppb/10 hrs with 14-25% contribution from fire sources. Vertical mixing and advection are the major drivers of changes in surface ozone. Model analysis indicates that advection dominates fire-related ∆O3 below 1 km on 12 November, while local photochemistry dominates on 13 November. These results quantify the different mechanisms through which fires can influence the vertical ozone budget and point out uncertainties in fire inventories that need to be addressed in light of the increasing role of wildfires on air quality.

A lightning nitrogen oxides (LNOx) emissions model using satellite-observed lightning optical energy is introduced for utilization in Air Quality modeling systems. The effort supports assessments of air-quality/climate coupling as related to the influence of LNOx on atmospheric chemistry. The Geostationary Lightning Mapper (GLM), International Space Station Lightning Imaging Sensor (ISS-LIS), and the Tropical Rainfall Measuring Mission (TRMM) LIS data are used to examine the efficacy of the method, extend the previously derived LNOx record, and demonstrate a path for using ISS-LIS observations to cross-calibrate regional LNOx estimates from the future global constellation of geostationary lightning observations. A detailed evaluation of the GLM dataset is provided to establish the robustness of observations for LNOx estimates and to make preliminary assessments of the LNOx emissions model. Seasonal and geographical variation, land/ocean contrast, and annual fluctuation in the GLM observed lightning activity and flash optical energy are provided. GLM detection substantially degrades with the increase in the field of view, resulting in 44% more flashes and 40% less optical energy observation by GLM-16 (compared to GLM-17) to the east of the middle-longitude between the two mappers (106.2°W). Regular horizontal striations are found in the optical energy product. On average, GLM flashes matched to the cloud-to-ground flashes have ~30% longer duration, 50-70% more extension, and ≥ 100% higher optical energy compared to the unmatched flashes (assumed to be intra-cloud). The results from summer-long chemical transport simulations using LNOx generated from the emission model agrees with previous studies and shows consistency across the GLM/LIS datasets.

The vertical accumulation of ozone and aerosol during an episode of the 2016 Southeastern United States Wildfires is analyzed by integrating a regional chemical transport model with ozonesonde, O$_3$ Differential Absorption Lidar (DIAL), ceilometer, surface monitors, and satellite products. The results indicate that measurements capture the vertical extent of the smoke plumes affecting the surface and upper air over Huntsville, AL, and also the enhanced ozone lamina in the plumes. Sensitivity simulations and tendency diagnostics characterize the chemical and physical processes affecting the vertical profiles downstream of the wildfires. The model results show that the net chemical ozone production (PO$_3$) dominates the daytime ozone accumulation by up to 19 ppb/10 hrs in the upper air over Huntsville. At the surface, the negative PO$_3$ is offset by positive O$_3$ contributions from vertical mixing and advection. Fire emissions increase the vertical ozone by affecting local chemical reactions, transportation, and vertical exchange. The dominant processes exhibit daily, diurnal, and vertical variability. Quantitatively, fire emissions increase the daytime positive PO$_3$ by up to 25\% in the upper air, and increase the daytime PM2.5 by up to 77\%. The capability of the regional model for reproducing the observations is explored. Increasing the fire aerosol emissions improves the model performance on domain-averaged PM2.5. The model captures the well-mixed aerosol in the boundary layer but fails to fully reproduce the densest plumes seen in the DIAL and satellite. The discrepancies are associated with poor satellite observing condition due to clouds and with uncertainties in emission inventories.