Fitting the statistical distributions to the daily rainfall amount in Peninsular Malaysia

Abstract

Daily rainfall data have classified according to four rain types of sequence of wet days (Type 1, 2, 3 and 4). The Gamma, Weibull, Kappa and Mixed Exponential are the four distributions tha have been tested to fot daily rainfall amount in Peninsular Malaysia. Parameters for each distribution were estimated using the maximum likelihood method. The selected model is chosen based on the minimum error produced by seven goodness of-fit (GOF) tests namely the median of absolute difference (MAD) between the empirical and hypothesized distributions, the traditional Emprical Distribution Function (EDF) Statistics which include Kolmogorov-Smirnov statistic D, Anderson Darling statistic A2 and Cramer-von-Mises statistic W2 and the new method of EDF Statistics based on likelihood ratio statistics. Based on these goodness-of-fit tests, the Mixed Exponential is found to be the most appropriate distribution for describing the daily rainfall amount in Peninsular Malaysia