Lightning Enhancement over Major Shipping Lanes

Using twelve years of high resolution global lightning stroke data from the World Wide Lightning Location Network (WWLLN), we show that lightning density is enhanced by up to a factor of two directly over shipping lanes in the northeastern Indian Ocean and the South China Sea as compared to adjacent areas with similar climatological characteristics. The lightning enhancement is most prominent during the convectively active season, November-April for the Indian Ocean and April-December for the South China Sea, and has been detectable from at least 2005 to the present. Meteorological factors are unable to explain these enhancements, and we conclude that aerosol particles resulting from shipping emissions perturb cloud microphysics, convection, and ice processes leading to enhanced lightning.