Modelling Daily Rainfall Amount in Pekanbaru City using Gamma and Some Extended Gamma Distribution

Abstract - Modeling rainfall is very important to be developed in managing natural resources to deal with the impacts of climate change. We modelled the daily rainfall for data recorded in Pekanbaru City from 1999 to 2008. the main goal of this study is to find the best fitting distribution to the daily rainfalls by using the maximum likelihood approach. for this purpose, Gamma distribution and some Extended Gamma Distribution will be used and tested to determine the best model to describe daily rainfall in Pekanbaru City. the extended gamma distribution meaning some mixture two and three gamma distribution, namely rani, shanker and sujatha distribution. the maximum likelihood method will be used to get the estimated parameter value from the distribution used in this study. the distributions will be selected based on graphical inspection probability density function (pdf), numerical criteria Akaike’s information criterion (AIC) and Bayesian Information Criterion (BIC). in most the cases, graphical inspection gave the same result but their AIC and BIC result differed. the best fit result was chosen as the distribution with the lowest values of AIC and BIC. in general, the Gamma distribution has been selected as the best mode