The electrical activity of a thunderstorm under high dust circumstances over Beijing metropolis region

Abstract

A rare dust-thunderstorm swept the Beijing area on April 15, 2021, generating frequent lightning, dirt precipitation, and gusting. Based on comprehensive data from satellite retrieval, in-situ observation, weather radar, and reanalysis data, this study investigated the effect mechanism of dust on electrical activity of this dust-thunderstorm. The results showed that dust from Mongolia were involved in the development and intensification of the thunderstorm. During the evolution of the thunderstorm, the ground electrical field changed positively with the highest value of 9 kV. PM2.5 and PM10 increased rapidly with the highest values of 1500 ug/m3 and 250 ug/m3 under the influence of dust. The positive cloud-to-ground (+CG) lightning accounted for a high percentage with an average ratio of more than 50%. The dust acting as effective ice nuclei (IN) and cloud condensation nuclei (CCN) invading the thunderstorm were likely to increase the content of ice-phase particles, resulting in a high proportion of +CG lightning. Considering the mechanism of CCN and IN on electrification, this study conducted further sensitivity simulation experiments on dust effect on dynamic-microphysics-electrification by the WRF-ELEC model, which coupled with a heterogeneous nucleation scheme for IN associated with aerosol concentration. The results indicate that the increases of dust influence the concentration and the size of different hydrometeor particles within this dust-thunderstorm, leading to changes in the charge structure and a significant increase in the proportion of +CG lightning.