Determination of the Best Fit Probability Distribution for Monthly Rainfall Data in Bangladesh

Abstract

An attempt has been made to determine the best fitted distribution to describe the monthly rainfall data for the period of 1979 to 2013 of distantly located stations in Bangladesh such as Chittagong, Dhaka, Rajshahi and Sylhet. The Normal, Lognormal, Gamma, Weibull, Inverse Gaussain and Generalized Extreme Value distributions are fitted for these purposes using the method of L-moment. The performances of the distributions are evaluated using three goodness-of-tests namely Kolmogorov-Smirnov, Anderson-Darling and Chi-Square test. Finally, goodness of fit test result are compared and generalized extreme value distribution is empirically proved to be the most appropriate distribution of the monthly rainfall data for the three selected station only Dhaka station provides good fit gamma distribution.