Effect of lightning activity on Surface NOx and O3 over a tropical station during pre-monsoon and monsoon seasons

Abstract

We study the effect of lightning activity on Surface NOx and O3 over Pune, India (18.54{degree sign}N, 73.81{degree sign}E), for the years 2005 to 2008 during thunderstorm events in pre-monsoon and monsoon period. Surface concentration of NOx is found to be increased significantly at the dissipation stage of thunderstorms. It is observed that increase in NOx greater than titration threshold level reduces the surface ozone concentration. However, in some cases when NOx increases but it does not reach the titration-threshold limit, it helps in the production of ozone. Thus, results suggest that lightning production of NOx inside a thunderstorm can lead to significant impacts on surface ozone concentrations in the tropics. Enhancement in NOx at the surface after thunderstorm activity is much greater in pre-monsoon periods compared to the monsoon period.