Analysis of thunderstorms in Bangladesh using ARIMA model

In this paper our main goal is to study the climatology and variability of the frequency of thunderstorm days over Bangladesh region throughout the year. It has been found that the mean thunderstorm days increase significantly from March to May, i.e. during the pre-monsoon season, although the graphical devices show that there does not seem to be much deviation from the occurrences of thunderstorms each year. The mean monthly and seasonal thunderstorm days were maximum in 1993, followed by that in 1997; whereas it was a minimum in the year 1980, with an extension in its frequency in the subsequent years 1981 and 1982. The coefficient of variation of both annual and seasonal thunderstorm days is minimum over the areas of maximum frequency of mean thunderstorm days and vice-versa. The time-domain analysis confirms that the occurrence happened to be maximum in the year 1991, although each and every state did not witness thunderstorms every year. Also some other time-domain models like autocorrelation and seasonal integrated moving average provide adequate evidence for exploring the number of thunderstorms which happen to confirm the trend of occurrence of thunderstorm over the years.