Thunderstorms and their Influence on Meteorology and Atmospheric Composition Over Southern Peninsular India

The study examines the long-term (2011-2023) analysis of thunderstorm and lightning activities and their impacts on local meteorology and air pollutants over Bengaluru. The diurnal thunderstorm events occur mainly in the late evening hours (1900–2100 IST) and on monthly maximum in May while minimum in January. Annually, Bengaluru experiences an average of 41 thunderstorms and 157 lightning strikes, both of which have shown a statistically significant upward trend at a 95% confidence level. The rate of increase is 3.41% per year for thunderstorms and 3.3% per year for lightning events. Local temperatures coupled with abundant moisture supply from the southwest/northeast monsoon creates a favourable condition for the initiation of thunderstorms over the region. This study also focused on the trend analysis of meteorological parameters and atmospheric compositions, a rising trend were found in rainfall (1.44 mm year–1), RH (0.74% year–1) & pressure (0.03 hPa year–1) whereas a slight declining trends in temperature (0.06 0C year-1) & wind speed (-0.02 ms-1 year–1). As the availability of heat and humidity are two main prerequisites for the occurrence of thunderstorm and hence the probability of severe thunderstorms may increase in future. The AOD, NO2 & O3 showed a significant increasing trend while no trend for SO2. The Pearson correlations showed the AOD, NO2 & SO2 concentrations are significant negatively correlated with wind speed but positively correlated with atmospheric pressure. A further study indicated a significant impact of thunderstorm on the air pollutants has also been quantified and it was observed that PM2.5 concentration gradually decreases after the commencement of thunderstorm while quick increase response (less than 1 hour) was observed in O3 and delay response (after 2:30 hours) in NO2 which may linked to lightning activities. The results reveal that thunderstorms can affect both the local meteorology as well as atmospheric pollutants and vice-versa from regional to global.