NO_x from lightning: 1. Global distribution based on lightning physics

Abstract

For CG energies we adopt a production rate of 10 x 1016 molecules NO/J based on the current literature. Using a method to simulate global lightning frequencies from satelliteobserved cloud data, we have calculated the LNOx on various spatial (regional, zonal, meridional, and global) and temporal scales (daily, monthly, seasonal, and interannual). Regionally, the production of LNO• is concentrated over tropical continental regions, predominantly in the summer hemisphere. The annual mean production rate is calculated to be 12.2 Tg N/yr, and we believe it extremely unlikely that this number is less than 5 or more than 20 Tg N/yr. Although most of LNO• is produced in the lowest 5 km by CG lightning, convective mixing in the thunderstorms is likely to deposit large amounts of NO• in the upper troposphere where it is important in ozone production. On an annual basis, 64% of the LNO• is produced in the northern hemisphere, implying that the northern hemisphere should have natural ozone levels as much as 2 times greater than the southern hemisphere, even before anthropogenic influences. The amount of 03 produced from this NOx is expected to exceed the stratospheric source by a factor of 1.5, and thus the hemispheric asymmetry in LNOx would lead to a significant excess of northern hemisphere 03 even in the preindustrial troposphere. (The monthly climatologies for LNO• on a 1 ø x 1 ø latitude-longitude grid can be obtained by e-mail to cprice@flash.tau.ac.il.)

Rapid intercontinental air pollution transport associated with a meteorological bomb

“…Values reported in the literature for the NO x produced per cloud-to-ground lightning flash vary considerably, for instance 6.7×10 26 molecules flash −1 (Price et al, 1997), 1.25-12.5×10 25 molecules flash −1 (Stith et al, 1999), or 8.1×10 25 molecules flash −1 (Huntrieser et al, 2002). DeCaria et al (2000) estimated that 3×10 26 molecules CGflash −1 are carried by the downdrafts.…”

“…Taking this last value, which is at the upper range of the more recent values reported in the literature, and assuming a 80% detection efficiency of CG flashes (note that this value may be too low for the second episode), it is estimated that 23.3 t NO 2 were produced in the first lightning episode below 1 km, and 118 t NO 2 in the second episode. IC flashes produce less NO x per flash than CG flashes (Price et al, 1997). DeCaria et al (2000) estimate that 1.4×10 26 molecules IC-flash −1 and 3×10 26 molecules CGflash −1 are carried in updrafts.…”

Nitric oxide production by simulated lightning: Dependence on current, energy, and pressure

“…In this experiment, peak current occurs at 30/•s. In natural lightning the time to peak varies widely, with a mean time to peal( of 5 its [Price et al, 1997]. …”

04/01035 Impacts of anthropogenic and natural NOx sources over the U.S. on tropospheric chemistry

“…7, 13, and 14. IC f lashes are believed to have significantly lower energies than CG f lashes and hence have a lower NO x production efficiency (15). Lightning production outside the U.S. is based on parameterization developed by Price et al (15) and satellite observation from OTD (13).…”