Upper tropospheric ozone production from lightning NO_x‐impacted convection: Smoke ingestion case study from the DC3 campaign

Abstract

As part of the Deep Convective Cloud and Chemistry (DC3) experiment, the National Science Foundation/National Center for Atmospheric Research (NCAR) Gulfstream-V (GV) and NASA DC-8 research aircraft probed the chemical composition of the inflow and outflow of two convective storms (north storm, NS, south storm, SS) originating in the Colorado region on 22 June 2012, a time when the High Park wildfire was active in the area. A wide range of trace species were measured on board both aircraft including biomass burning (BB) tracers hydrogen cyanide (HCN) and acetonitrile (ACN). Acrolein, a much shorter lived tracer for BB, was also quantified on the GV. The data demonstrated that the NS had ingested fresh smoke from the High Park fire and as a consequence had a higher VOC OH reactivity than the SS. The SS lofted aged fire tracers along with other boundary layer ozone precursors and was more impacted by lightning NO x (LNO x ) than the NS. The NCAR master mechanism box model was initialized with measurements made in the outflow of the two storms. The NS and SS were predicted to produce 11 and 14 ppbv of O 3 , respectively, downwind of the storm over 2 days. Sensitivity tests revealed that the ozone production potential of the SS was highly dependent on LNO x . Normalized excess mixing ratios, ΔX/ΔCO, for HCN and ACN were determined in both the fire plume and the storm outflow and found to be 7.0 ± 0.5 and 2.3 ± 0.5 pptv ppbv À1, respectively, and 1.4 ± 0.3 pptv ppbv À1 for acrolein in the outflow only.

Chemical processes related to net ozone tendencies in the free troposphere

“…The median daily net ozone production for the HOOVER case is 22.67 ppbv d −1 (range: 19.47-26.11 ppbv d −1 ) and about a factor of 2-4 larger than values reported in the literature for NH mid-latitudes, e.g. ∼ 15 ppbv d −1 during PRESTORM, Oklahoma (Pickering et al, 1990(Pickering et al, , 1992a, 10-13 ppbv d −1 during STERAO-A over North America (DeCaria et al, 2005), up to 5 ppbv during EULINOX over Europe (Ott et al, 2007), and 5-7 ppbv d −1 during DC3 over North America (Apel et al, 2015).…”

The impact of lightning on tropospheric ozone chemistry using a new global lightning parametrisation

“…This is a particularly important region because it is the region of most efficient ozone production (Dahlmann et al, 2011). Understanding how the magnitude of lightning flash rate or concentration of emissions affects ozone production is an ongoing area of research, and so far has focussed on individual storms or small regions (Allen and Pickering, 2002;DeCaria et al, 2005;Apel et al, 2015). DeCaria et al (2005) found that whilst there was little ozone enhancement at the time of the storm, there was much more ozone production downstream in the following days.…”

Sources and characteristics of summertime organic aerosol in the Colorado Front Range: perspective from measurements and WRF-Chem modeling

“…The auxiliary gas-phase data used in this analysis are carbon monoxide (CO) by vacuum UV resonance fluorescence (Gerbig et al, 1999); nitric oxide (NO) and nitrogen dioxide (NO 2 ) by chemiluminescence (Ridley et al, 2004); ethane (C 2 H 6 ) by infrared spectrometry (Richter et al, 2015); aromatic and biogenic species by online proton-transfer-reaction mass spectrometry (Lindinger et al, 1998;de Gouw and Warneke, 2007); hydrogen cyanide (HCN); i-pentane and npentane by online cryogenic gas chromatography-mass spectrometry (GC-MS) (Apel et al, 2015); methylcyclohexane and n-octane by offline analysis of whole air canister samples (WAS) by GC-MS (Colman et al, 2001); nitric acid (HNO 3 ) by chemical ionization mass spectrometry (CIMS) using SF − 6 as the reagent ion (Huey et al, 1998); peroxyacyl nitrates (PAN and PPN) by I − CIMS (Zheng et al, 2011); alkyl nitrates by thermal dissociation laser-induced fluorescence (Day et al, 2002); and hydroxyl (OH), hydroperoxy (HO 2 ), and alkyl peroxy (RO 2 ) radicals by CIMS (Mauldin et al, 1998;Hornbrook et al, 2011;Ren et al, 2012). NO y was calculated by summing up the individually measured nitrogen oxide species, namely NO, NO 2 , HNO 3 , particulate nitrate, PAN, PPN, and alkyl nitrates.…”