Thunderstorm Days and Lightning Activity in Association with El Nino

Abstract

El Niño and La Niña events are well known to be associated with significant monthly/seasonal climate anomalies at many places around the globe. The teleconnections of the Indian monsoon with El Niño/ Southern Oscillation is widely known, which form the basis for seasonal prediction of the monsoon. However, not much is known about its influence on thunderstorm days and lightning activity. In view of this, a study is attempted on the analysis of association between El Nino and thunderstorm activity in terms of thunderstorm days and lightning flashes. Present study is based on the data on lightning flashes from Lightning Imaging Sensor (LIS), which is a space borne optical sensor on the Tropical Rainfall Measuring Mission (TRMM) to detect tropical lightning. The data on lightning flashes from LIS are available from 1998 onwards. Therefore, the analysis is done for all the El Niño episodes which cover the years 1998-2013. The thunderstorm day data are collected from India Meteorological Department for the same period. The study reveals that during El Nino events, the number of thunderstorm days decreases and on the other hand there is an increase in lightning flashes, flash rates and flash density. During El Nino events, Southeast Asia gets warmer and drier which may result in the fewer thunderstorms. The fewer thunderstorms that occurred during El Niño episodes are much more intense, convectively more active and therefore produce more lightning.