On the association between lightning and precipitation microphysics

Lightning is one of the most important extreme weather conditions and is associated with heavy convective rain and thunderstorms. However, the present understanding of such systems as well their effect on precipitation characteristics are insufficient for proper modelling. In this paper, the rain microphysics is studied at Kolkata using an optical disdrometer in relation to the lightning activities. Lightning information is obtained from ground based World Wide Lightning Location Network and Lightning Imaging Sensor onboard International Space Station. The associated cloud features are studied with Doppler weather radar and MODIS satellite measurements. Results indicate significant change in rain microphysics between events with lightning and without lightning. The cloud microphysics indicates that the cloud top temperature is lower and cloud effective droplet size is smaller in case of lightning in comparison to non-lightning situation. On the other hand, large drops are abundant while small drops are less in numbers in rain with lightning than rain without lightning. The a value in Z-R relation is found to be significantly higher for rain with lightning than other type. The rain attenuation is also found to have significant variation under these two conditions. The implication of such varied rain microphysics on GPM Ku and Ka band radar are also reported.