GUWAHATI, Sept 28 - The Brahmaputra Valley has the highest monthly lightning flash rate between April and May, when thunderous activity ushers in the annual monsoon. The scientific paper, �TRRM-based Lightning Climatology� authored by Daniel J Cecil and Richard J Blakeslee of the NASA Marshall Space Flight Center (MSFC), Huntsville and Dennis E Buechler of the University of Alabama, Huntsville and uploaded to the NASA Technical Reports Server (NTRS) has stated this.
It states that the peak monthly average flash rate at 2.5 degree scale is 18 flashes per sq km or per square mile, from early April to early May in the Brahmaputra Valley. Lightning decreases in this region during the monsoon season, but increases further north and west.
Space-borne optical sensors Optical Transient Detector (OTD) on the MicroLab-1 satellite and Lightning Imaging Sensor (LIS) on the Tropical Rainfall Measuring Mission (TRMM) satellite have detected lightning for nearly 16 years since 1995 for studying the phenomenon of lightning. For conducting this study, the team was associated with the NASA MSFC.
Though the results of the study are similar to those found from the earlier climatological studies, the length of the data collected during this study allows more detailed analyses with less spatial or temporal smoothing, says the paper.
It further states that most continental regions away from the equator have an annual cycle with lightning flash rates peaking in late spring or summer. The main exceptions are India and Southeast Asia, with springtime peaks in April and May. A monthly average greater than 13 flash per sq km or per square mile from early August to early September in northern Pakistan also exceeds any monthly averages from Africa, despite central Africa having the greatest yearly average in this respect, says the paper.
However, a Venezuela lake has been found to be the location of the highest number of lightning flashes in a year. Ella Davies said, in a write-up carried by the BBC Earth on August 10, 2015, that on a good night, one lake in Venezuela hosts thousands of lightning strikes every hour. The phenomenon is known variously as the Beacon of Maracaibo, Catatumbo lightning or � cue dramatic roll of thunder � the �everlasting storm�. That last one might be a slight exaggeration, but where the Catatumbo River meets Lake Maracaibo there is an average of 260 storm days every year. The night sky is regularly illuminated there for nine hours, with thousands of flashes of naturally produced electricity.
Lake Maracaibo has earned a place in the Guinness Book of World Records for the �highest concentration of lightning� with 250 lightning flashes per sq km each year.