Lightning activity and its connection with weather-related parameters over Sri Lanka

Abstract

This study analyzed lightning activity along Sri Lanka using lightning imaging sensor for a 17-year period (1998–2014). To understand the influence of various parameters on the lightning activity, we investigated various meteorological parameters such as convective precipitation, relative humidity, cloud top temperature, cloud base height, convective available potential energy, total precipitable water, rain dynamic index, humidity index, convection inhibition, lifted index, K-index, total totals index, show alter index, vertical velocity and dew point depression (Dpd). North-western, Western, Southern and Sabaragamuwa regions of Sri Lanka showed high lightning activity. The analysis revealed different seasonal variations in lightning activity. The pre-monsoon season showed the maximum frequency, while winter witnessed the least. In addition, wind patterns embedded with moisture seem to influence regional variations over Srilanka. The westerly winds might influence lightning activity over Srilanka. We investigated the variations of different meteorological parameters for 40 lightning and no lightning days during the study period. During lightning days, the VV values show negative values with strong lightning and convection potential and strong atmospheric updrafts. Higher atmospheric levels have been found to contain dry air, and lower atmospheric levels have been found to contain moist air on lightning days. Extremely unstable atmospheric conditions that favour intense lightning activity were indicated by LI values less than −4.