Mixed Geometric Truncated Poisson Model for Sequences of Wet Days

Present study is aimed to propose the mixture of geometric distribution with the truncated Poisson model (MGTPD) as the alternative probability model to describe the distribution of wet (dry) spells in daily rainfall events. In order to compare the performance of this new model with the other five existing probability models in fitting the distribution of wet spells, daily rainfall data from five stations over Peninsular Malaysia for the period of 1975 to 2004 was considered. In determining the most successfully fitted and the best fitting model to represent the observed distribution of wet spells at each station, a Chi-square goodness-of-fit test was used. The results demonstrated that all the data sets were found to successfully fit the new proposed model, the MGTPD. Moreover, this model was also found to produce a better fit than the existing mixed geometric with Poisson model (MGPD) in describing the distribution of wet spells over the five selected stations.