Ozone and point discharge measurements under thunderclouds

Abstract

Short duration increases in the concentration of atmospheric ozone have been observed beneath active New Mexican thunderstorms in the vicinity of an exposed and grounded sharp metal rod. These ozone transients immediately follow the emission of charge into the air from the metal point under the influence of atmospheric electricity. The increases are greater when they are associated with negative charge emission than when they are associated with positive; the maximum ozone concentration above lightning‐induced emission of negative charge has been about 6.4 times that of the fine weather concentration (about six ozone molecules per hundred million air molecules). Longer duration increases in the atmospheric ozone to about 1.5 times the prestorm concentration are found above a collection of natural grass points when overhead clouds are electrified with a net positive charge. Our comparison of the ultraviolet radiation pulses from negative and positive point to plane discharges suggests to us a photochemical explanation for the relatively large production of ozone by negative charge emission. Whereas much of the ozone found aloft appears to have been transported by updrafts from the surface, the concentrations observed in an electrified cloud were greater than those near the earth. We find that ozone is produced by the point discharge from the surfaces of water droplets under intense electric fields; this process may account for some of the ozone observed in thunderclouds.

Influence of corona discharge on the ozone budget in the tropical free troposphere: a case study of deep convection during GABRIEL

“…Ozone formation in inlet lines or on the fuselage of aircrafts has been documented to lead to measurement artefacts (Ridley et al, 2006, and references therein) whereas experimental evidence for ozone production by electrical discharges in the free troposphere is inconclusive. Shlanta and Moore (1972), Winterrath et al (1999) and Zahn et al (2002) suggested direct ozone production from corona discharge to explain the observed enhanced mixing ratios in a thunderstorm cloud and convectively active areas, respectively. In these studies no yield of O 3 molecules per flash is given.…”

“…However, experimental evidence from field studies is very sparse. It was first postulated by Shlanta and Moore (1972) that discharges might occur on cloud water droplets or ice particles in highly electrified environments. Griffing (1977) also linked corona discharges to streamer filaments or the surrounding area of lightning channels.…”

The global lightning-induced nitrogen oxides source

“…Nevertheless, a few studies reported partially large O 3 increases exceeding several 100 nmol mol −1 Zahn et al, 2002;Güsten et al, 2003) near thunderstorms using various observation methods (Dobson et al, 1946;Orville, 1967;Shantla and Moore, 1972;Clarke and Griffing, 1985;Jadhav et al, 1996;Borra et al, 1997;Suhre et al, 1997;Randriambelo et al, 1999;Winterrath et al, 1999). However, ground-based spectroscopy of visible light absorption by O 3 may suffer from multiple scattering in the clouds (Platt et al, 1997); in-situ measurements of O 3 by ultraviolet absorption near deep convective events with high water vapour concentration changes are prone to an instrument interference with water vapour (Meyer et al, 1991;Huntrieser et al, 2007); and O 3 (also NO and NO 2 ) may be formed by local corona discharges at the instrument's inlet in intense electrical fields inside thunderstorms (Zahn et al, 2002;Ridley et al, 2006).…”

Observations of ozone production in a dissipating tropical convective cell during TC4

“…3), but globally, convection reduces tropospheric O 3 by 13%. Tropical Atlantic SCIAMACHY Martin et al (2007) studies vary widely, with some suggesting strong enhancements of O 3 (e.g., Schlanta and Moore, 1972;Dickerson et al, 1987) and others suggesting no such enhancements and potential losses of O 3 (e.g., Ridley et al, 2006;Ott et al, 2007;Salzmann et al, 2008). Results from these previous studies are summarized in Table 1.…”