Climatology of Lightning Activity over the Indian Seas

Abstract

The climatology of lightning activity over the Indian seas (Arabian Sea (AS) and Bay of Bengal (BoB)) has been studied using monthly satellite-based lightning flash count grid (0.5°× 0.5°) data from 1998 to 2007. These data have been used to investigate the annual and seasonal variations in lightning activity over the Indian seas. It was found that annual variations in flash rate density and sea surface temperature (SST) show a bimodal pattern with the first peak occurring in May and the second in October. The correlation coefficients between flash rate density and SSTs are 0.76 and 0.65 for the AS and BoB, respectively. Further, the relationship between flash rate density and a low pressure system (LPS) over the BoB shows that the formation of severe tropical cyclonic storms starts during April with the maximum number of storms forming during August. The performance of monsoon on a seasonal and monthly basis depends on the total number of lows, the formation of a depression in the monsoon trough, and the number of days with an LPS. Secular decreases in the number of lows and monsoon depressions were observed in 2000 , and 2004, results indicate that the peaks in SST during April and September/October over the AS and the BoB may be responsible for advancing the onset of the southwest and northeast monsoon by 30-40 days.RÉSUMÉ [Traduit par la rédaction] Nous avons étudié la climatologie de la foudre dans les mers de l'océan Indien [mer d'Arabie (MA) et golfe du Bengale (GB)] à l'aide des données mensuelles satellitaires sur grille (0,5°× 0,5°) de compte d'éclairs de 1997 à 2007. Nous avons utilisé ces données pour examiner les variations annuelles et saisonnières dans l'activité de la foudre dans les mers de l'océan Indien. Nous avons trouvé que les variations annuelles dans la densité de fréquence des éclairs et dans la température de surface de la mer affichent une configuration bimodale, avec un premier pic se produisant en mai et un second en octobre. Les coefficients de corrélation entre la densité de fréquence des éclairs et la température de surface de la mer sont de 0,76 et 0,65 pour la MA et le GB, respectivement. De plus, la relation entre la densité de fréquence des éclairs et un système de basse pression dans le GB montre que la formation de fortes tempêtes cycloniques débute en avril avec un nombre maximum de tempêtes se formant en août. La performance de la mousson sur une base saisonnière et mensuelle dépend du nombre total de systèmes de basse pression, de la formation d'une dépression dans le creux de mousson et du nombre de jours avec un système de basse pression. Nous avons observé des diminutions séculaires dans le nombre de systèmes de basse pression et de dépressions de la mousson en 2000, 2002 et 2004. Dans l'ensemble, les résultats indiquent que les pics dans la température de surface de la mer en avril et en septembre/octobre dans la MA et le GB peuvent expliquer l'avance de 30 à 40 jours de la mousson du sud-ouest et de la mousson du nord-est.

Climate indicators for lightning over sea, sea–land mixed and land‐only surfaces in India

“…LIS system is of the National Aeronautics and Space Administration's Earth Observing System on the Tropical Rainfall Measuring Mission satellite was launched on 28 November 1997 at an altitude of 350 km and at about 400 km since August 2001. The higher altitude (at an orbital inclination of 35°) gives a corresponding larger field of view for each of the sensor pixels, swath and longer sampling duration (Cecil et al , ; Tinmaker et al , ). Lightning flash illuminates the top of cloud significantly larger than the field of view of an LIS pixel, where the LIS detection threshold setting is unaltered after the boost for its detection efficiency.…”

“…LIS is a satellite-borne system that detects the lightning flashes with storm-scale (spatial) resolution (4-7 km) over a large region of the Earth's surface (Christian et al, 1999;Bond et al, 2002). higher altitude (at an orbital inclination of 35 ∘ ) gives a corresponding larger field of view for each of the sensor pixels, swath and longer sampling duration (Cecil et al, 2014;Tinmaker et al, 2014). Lightning flash illuminates the top of cloud significantly larger than the field of view of an LIS pixel, where the LIS detection threshold setting is unaltered after the boost for its detection efficiency.…”

An inclusive study of lightning at various temporal resolutions over North East India using hi-res satellite data

“…Compared to pre-monsoon and monsoon season, lightning activity drops during post-monsoon season, resulting in a completely different spatial pattern of LFRD. The shifting of lightning disturbances and onset of north east monsoons by Tinmaker, et al[73] and Tinmaker, et al[74]. The LFRD for this season ranges from0.005 to 2.2 flashes km -2 season -1 .…”

Spatio-temporal variability of lightning climatology and its association with thunderstorm indices over India

“…(Cecil et al, 2014;Dewan et al, 2018b;Taszarek et al, 2019, Lizandro et al, 2020. Many studies take place on lightning and its correlation with other indices over the Indian region (Saha et al, 2016, Murugavel et al, 2014, Tinmaker et al, 2014Kandalgaonkar et al, 2003, 2005Pawar et al 2012;Ranalkar and Chaudhari et al, 2009;Penki and Kamra et al, 2013). With the increase in CAPE, the lightning activity also increases; South Asia is one of the highest lightning impacted regions (>30 fl /km 2 ) analyzed by (Albrecht et al, 2016), mainly Himalayan foothills.…”