Analysis of cloud-to-ground lightning and its relation with surface pollutants over Taipei, Taiwan

Abstract

Abstract. Premonsoon (March-April) cloud-to-ground (CG) lightning activity over Taipei, Taiwan, is analyzed in relation to surface pollutants like particulate matter (PM 10 ), sulfur dioxide (SO 2 ), nitrogen oxides (NO x ) and ozone (O 3 ) concentration for a period of 6 years (2005)(2006)(2007)(2008)(2009)(2010). Other surface parameters like aerosol optical depth and cloud top temperature are also investigated taking data from Moderate Resolution Imaging Spectroradiometer satellite products. Results reveal that SO 2 is more strongly associated with CG lightning activity compared to PM 10 concentration. Other surface pollutants like NO x and O 3 also show strong linear association with CG lightning flashes. Additional investigations have also been performed to extreme lightning events, particularly to a few long-lasting lightning episodes considering the concentrations of NO x and O 3 found on days with no lightning activity as representative of the background concentration levels of the said two parameters. Results indicate that the NO x concentration on days with lightning activity is more than 2-fold compared to the non-lightning days while the O 3 concentration is increased by 1.5-fold. Such increase in NO x and O 3 concentration on days with lightning strongly supports the transport phenomena of NO x and O 3 from the upper or middle troposphere to the lower troposphere by downdraft of the thunderstorm during its dissipation stage. Overall, studies suggest that enhanced surface pollution in a near-storm environment is strongly related to the increased lightning activity, which in turn increases the surface NO x level and surface O 3 concentration over the area under study.

Cloud — Aerosol interaction during lightning activity over land and ocean: Precipitation pattern assessment

“…The study shows that high aerosol concentration over land enhances the lightning activity. The study also supports that high-frequency weather phenomena like lightning activity are not only influenced by meteorological parameters but also influenced significantly by tropospheric particulate matters (Kar and Liou, 2014).…”

Lightning NO x and Impacts on Air Quality

“…Reported surface-NO x enhancements associated with thunderstorms are scare. Those that exist report peak values of about 40 ppbv over India, 25 ppbv over Taiwan, and 30 ppbv (mostly as NO 2 ) over northern Alabama, and persist from minutes during the day to a few hours at night [16,64,96,114,115,165]. However, reported surface concentrations never exceed current health guidelines for short-term NO 2 exposure (1-h mean 100 ppbv [174]).…”

“…However, two studies report positive correlations between observed lightning flash rates and surface concentrations of NO x and ozone over both Kolkata, India ( O 3 / NO x = +0.6 ppbv/ppbv) [96] and Taipei, Taiwan ( O 3 / NO x = +1.3 ppbv/ppbv) [64], suggesting that ozone production was always maintained over the megacities. Surface NO x associated with thunderstorms has also been observed to titrate ozone at nighttime, such as a 41 ppbv increase in NO x associated with a 26 ppbv decrease in ozone during the evening of Aug 8, 2012 over Hyderabad, India [16,165].…”

Role of lightning phenomenon over surface O3 and NOx at a semi-arid tropical site Hyderabad, India: inter-comparison with satellite retrievals

“…On the other hand, Middey and Chaudhuri (2013) observed an increase in concentration of O 3 at Kolkata, India, after a thunderstorm event, which was attributed to NO 2 photolysis. Kar and Liou (2014), Ott et al (2010), andMinschwaner et al (2008) reported an increase in the concentration of O 3 associated with lightning. The possible processes include advection of polluted air from the urban environment, photochemical production by lightning, downward mixing of stratospheric air, or local production from within the thunderstorm (Minschwaner et al 2008).…”

“…7b) with a weak correlation between these pollutants on lightning day compared to the monthly mean. These variations suggest References Pawar et al 2012, Middey and Chaudhuri 2013, and Kar and Liou 2014 that the dissimilarity in these sources on the event day is due to the NO x formed by lightning.…”