Comparison of estimation techniques for generalised extreme value (GEV) distribution parameters: a case study with Tasmanian rainfall

Generalised extreme value (GEV) distribution is traditionally applied to model extreme event and their return period. There are three parameters (location, scale and shape) in GEV distribution, which needs to be determined before its application. Different techniques have been developed to estimate the parameters of the GEV distribution. There is no specific guidance regarding the optimal method for estimating the parameters of the GEV distribution. This paper investigated the sensitivity of different parameters estimation techniques which are being commonly used in the application of the GEV distribution. Stationary GEV was adopted for the homogeneous data sets; whereas, non-stationarity GEV was implemented for the non-homogeneous data sets. Four methods were applied in the estimation of the GEV distribution parameters for four different timescales. The methods were applied in extreme rainfall modelling using extreme rainfall data in Tasmania, Australia as a case study. It was found that adoption of any GEV parameter estimation methods does not change the GEV type in Tasmanian extreme rainfall. The length of the data series has significant influence on the values of the GEV distribution parameters. The Fréchet type GEV distribution is suitable in most of the analysed rainfall stations in Tasmania.