Lightning activity within tropical cyclones in the South West Indian Ocean

Abstract

Lightning activity within 70 tropical cyclones in the South West Indian Ocean is studied using a large data set (2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013) provided by the World Wide Lightning Location Network (WWLLN). The radial and azimuthal distributions of lightning flashes are analyzed in three different regions of the basin: the open ocean, the Mozambique Channel, and the oceanic region up to 400 km off the eastern coast of Madagascar (ECM). Over the open ocean, lightning activity detected by the WWLLN is mainly found in the eyewall and decreases outward, regardless of storm intensity. Lightning activity in the eyewall of tropical cyclones is higher than in the eyewall of tropical storms. The front and the right quadrants (225 • to 45 • ) relative to the storm motion are the regions where lightning flashes are preferentially detected. Near the ECM, lightning density in the eyewall, the inner rainbands, and the outer rainbands is quite similar, presumably owing to the proximity of land. When the system reaches tropical cyclone strength, lightning activity is mainly found in the left and rear quadrants relative to storm motion. In the Mozambique Channel, the radial and azimuthal distributions of lightning flashes are complex due to the geographical configuration of this subdomain. The relationships between lightning activity and intensity change have also been investigated for systems over the open ocean. The proportion of periods with lightning activity is higher during rapid intensity changes of tropical cyclones. During tropical storm stage, lightning activity in the outer rainbands starts increasing 18 h before a rapid intensification period.

Enveloped Eyewall Lightning: The EEL Signature in Tropical Cyclones

“…The findings of Price et al (2009) are similarly seen in studies from Abarca et al (2011), Bovalo et al (2014, and Zhang et al (2015). Abarca et al (2011) used WWLLN data to look at 24 TCs in the Atlantic Basin, and found that intensifying TCs had up to twice as many lightning flashes in the inner core as TCs that did not intensify.…”

“…Abarca et al (2011) used WWLLN data to look at 24 TCs in the Atlantic Basin, and found that intensifying TCs had up to twice as many lightning flashes in the inner core as TCs that did not intensify. Using WWLLN data in the Southwest Indian Ocean, Bovalo et al (2014) studied 70 TCs between 2005 and 2013. Periods of increased lightning activity were found to be correlated with periods of rapid intensity change in those TCs.…”

Terrestrial gamma ray flashes due to particle acceleration in tropical storm systems

“…Studies of thunderstorms that occur over land find that the sum of CG and intracloud (IC) strikes (total lightning) are well correlated with updraft speed and thunderstorm convection structure [ Wiens et al , ]. Total lightning has also been used to probe the convective evolution and intensity of tropical storms [ De Maria et al , ; Bovalo et al , ]. Fierro et al [] used data from LASA (Los Alamos Sferic Array) [ Shao et al , ] to study the rapid intensification of Hurricanes Rita, Katrina, and Charley.…”

Characteristics of Thunderstorm Structure and Lightning Activity Causing Negative and Positive Sprites

“…The World Wide Lightning Location Network (WWLLN; Bovalo et al, ) global map with lightning stroke positions updated in every 10 min is used for real time locating the center of strong electrical activity and for adjusting the pointing azimuth of the camera. Since the detection efficiency of WWLLN is low, we also use the local lightning detection network, the infrared weather maps, and the Doppler radar images for locating the electrical center of the potential sprite‐producing thunderstorm.…”